[meteorite-list] Meteorite Picture of the Day
Today's Meteorite Picture of the Day: Gold Basin Contributed by: Bernd Pauli http://www.tucsonmeteorites.com/mpod.asp __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] terrestrial ages of finds ?
List experts, Does any kind of compilation exist giving the terrestrial ages (experimentally determined) of FINDS, in particuler concerning NWAs or finds from hot deserts ? Thanks for sharing any kind of info on this. Kind regards, Zelimir -- Prof. Zelimir Gabelica Université de Haute Alsace ENSCMu, Lab. LPI-GSEC, 3, Rue A. Werner, F-68093 Mulhouse Cedex, France Tel: +33 (0)3 89 33 68 94 Adam Hupe raremeteori...@yahoo.com a écrit : I will not debate the legacy of Antarctic meteorites. They have had a wonderful history and their contribution to science has been invaluable. Most researchers are sample oriented and are not biased by find location but there are still a few that cling to legacy. Antarctica had a a two decade plus head start in the abstract/paper queue so naturally there are more documents. Ten years ago, maybe one in ten papers were on hot desert finds. Now, I estimate about 50%. At this rate, as very important samples from NWA and other deserts enter the queue, it will not be long before these finds handily overtake Antarctica by a wide margin in the business of science. In other words; There is not enough material coming out of Antarctica anymore to reverse the current trend which favors the hot desert meteorites for research material in the future. Adam __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] terrestrial ages of finds ?
Hello Zelimir and List, Zelimir inquires: Does any kind of compilation exist giving the terrestrial ages (experimentally determined) of FINDS, in particuler concerning NWAs or finds from hot deserts? Wlotzka F. (1993) A weathering scale for the ordinary chondrites (Meteoritics 28-3, 1993, A460). Wlotzka F. et al. (1994) 14C terrestrial ages of meteorites from Açfer, Algeria (in Workshop on Meteorites from Cold and Hot Deserts, Nördlingen, July 1994, LPI Tech. Rep.9. Wlotzka F. et al. (1995) 14C terrestrial ages of meteorites from Acfer, Algeria (In Workshop on Meteorites From Cold and Hot Deserts, eds. L. Schultz et al., Lun.Plan.Inst.Tech.Rep. 95-02, Houston, Texas). Jull A.J.T. et al. (1990) Distribution of terrestrial age and petrologic type of meteorites from western Libya (GCA 54, 2895-2898). Jull A.J.T. et al. (1991) Terrestrial ages and petrologic description of Roosevelt County meteorites (abs. Lun.Plan. Sci. 22, 667-668). Jull A.J.T. et al. (1993) 14C terrestrial ages of meteorites from desert regions: Algeria and Australia (abs. Meteoritics 28-3, 1993, 376). Jull A.J.T. et al. (2002) Terrestrial ages of some meteorites from Oman (MAPS 37-7, 2002, A074). P.A. Bland et al. (1995) Weathering of ordinary chondrites from Algeria and Australia as a climatic indicator (abs. Meteoritics 30-5, 1995, 487). Schultz L. et al. (1998) Ten new meteorites from the Ténéré Desert (Niger): Classification, noble gases, cosmogenic radionuclides, and terrestrial ages (Meteoritics 33-4, 1998, A138). Al-Kathiri A. et al. (2005) Weathering of meteorites from Oman: Correlation of chemical and mineralogical weathering proxies with 14C terrestrial ages and the influence of soil chemistry (Meteoritics 40-8, 2005, pp. 1215-1239). Welten K.C. et al. (2004) Exposure history and terrestrial ages of ordinary chondrites from the Dar al Gani region, Libya (MAPS 39-3, 2004, 481-498). Stelzner Th. et al. (1996) The study of weathering products of meteorites by means of evolved gas analysis (Meteoritics 31-2, 1996, 249-254). Cheers, Bernd __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica)
But Jeff! This shall be: The Earth:o And now I hit 36,000 times the space-bar until I reach, almost a football-field wide to the right, the inner boarder of the inner asteroid main-belt. Does it then really matters so much, that an object from out there hits the little letter o more on top or more to the side? Hot desert meteorites do have three strong advances compared to the Antarctic finds. Within all classes they outnumber the Antarctic finds by far, regarding the representation of distinct fall events. On average the individual weights/masses of the hot desert finds are much larger than those of the cold desert finds. The procurement costs for hot desert meteorites are only a small fraction of the acquiring costs of the Antarctic finds. (Ok. The latter perhaps not for the individual scientist/institute who gets Antarctic samples granted for free, but somebody has to pay the infrastructure, equipment, personnel etc. of the Antarctic expeditions - in general the tax-payers of those countries taking part in the Antarctic searching campaigns). that the degree of weathering in Antarctic specimens is, overall, much less. True is, that Antarctic meteorites seem to weather half as fast as desert finds (I remember to have read some gross figures), and that they suffer from a different form of contamination, but seen the A-B-C-scheme versus the W0-W5-scheme, I dare to presume to say, that also that assertion is outdated today. The freshness of the hot finds is of course a function of the number of finds too. Don't forget that the very vast majority of the hot desert finds remains unclassified and unrecorded. Reasons are a lack of places for classification and of funds; the low scientific gain to be expected by working on ordinary chondrites, thus not justifying the necessary amount of funds and qualified manpower to classify them and finally economical considerations by the producers of the hot desert finds (remember those times, when NWA-OCs had cost less than Suisse cheese). The reasons for this are historical and curatorial. Only indirectly. At least the reasons aren't scientifical ones at all, but the prime reason is politics. Indeed several research facilities and institutional collections impose themselves a complete abdication of hot desert meteorites, though that is caused by legal imponderabilia. As we all know - let it be a lack of knowledge, let it be the self-interest of a few - some countries either perceive the circumstance, that meteorites do land on their territory already as a human achievement, and as a special national achievement, although the falls of stones are independent from topographic factors unlike the other natural precipitations like rain, snowfall, hail, dew and subsume therefore meteorites under the legislation of cultural goods or they reckon meteorites among the natural resources, although they aren't mined and not so many other goods come to my mind than my beloved mouse-milk (I read a pint costs 2k$), which are the same plentiful like meteorites and also I heard that using meteorites as a resource is regarded since the end of the bronze-age as somewhat optimistic.. or they protect them by law as natural monuments, which make meteorites, if they don't have that caliber (huh, uncle Alex, I almost wrote rogue wave) of the Hoba whopper or the Cape York masses or if we don't speak about crater-related strewnfields, to the smallest and most invisible monuments in existence. I don't know any piece of advice, that question the professional meteorite scientists have to discuss, Unfortunately they haven't any other global forum than the MetSoc for that, which is by its agenda apolitical. Well, if I dare to speak for us collectors, who can't have such a scientific or academic access to the meteorites, but often a more historical one, Our hearts are bleeding, whenever we miss in the Grand Collections of Calcutta, Vienna, London, Paris, Berlin, Moscow, Washington a second exhibition hall at least as large as the main meteorite exhibition or at least a storage in the depot facilities as large as that one for the historic ones, filled with the opulence of the meteorites of OUR times: The hot desert meteorites. I think, also in my senile retrospective, that it was an enormous mistake to miss out in that, which once will be called by our grandchildren The Golden Age of Meteorites. And here ends my annual standard rant ;-) Which, note!, has lost its anger (since I work on finding a Reimer-Tiemann-reaction in the field of meteorites). But let us sum up: The discussion of Good meteorite vs. Bad meteorite is a debate of the late 1990s/very early 2000s. Left today is rather: Good meteorite vs. Evil meteorite, isn't it? (However, they're all aliens). Slowfinger, Martin -Ursprüngliche Nachricht- Von: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von
Re: [meteorite-list] terrestrial ages of finds ?
Bernd, I was at 100% sure you will be the first to reply and bring a positive answer to my request. Definitely, your info database is invaluable! On behalf of the whole List (and of the whole meteorite community in general), I wish to express you a warm THANK YOU! Best wishes to all, Zelimir BTW: who is going to visit the Munich show (Oct 25-27)? Link (among many others, see Google): http://www.tradefairs.com/Trade_Fairs/The_Munich_Show_Mineralientage_Muenchen/2013/World_of_Minerals_Gems_Jewellery_and_Fossils/14,,7026,203625,0,2.html. I expect to be there probably on Thursday Oct 24 and Friday Oct 25 and be happy to meet many of you there... Z -- Prof. Zelimir Gabelica Université de Haute Alsace ENSCMu, Lab. LPI-GSEC, 3, Rue A. Werner, F-68093 Mulhouse Cedex, France Tel: +33 (0)3 89 33 68 94 Bernd V. Pauli bernd.pa...@paulinet.de a écrit : Hello Zelimir and List, Zelimir inquires: Does any kind of compilation exist giving the terrestrial ages (experimentally determined) of FINDS, in particuler concerning NWAs or finds from hot deserts? Wlotzka F. (1993) A weathering scale for the ordinary chondrites (Meteoritics 28-3, 1993, A460). Wlotzka F. et al. (1994) 14C terrestrial ages of meteorites from Açfer, Algeria (in Workshop on Meteorites from Cold and Hot Deserts, Nördlingen, July 1994, LPI Tech. Rep.9. Wlotzka F. et al. (1995) 14C terrestrial ages of meteorites from Acfer, Algeria (In Workshop on Meteorites From Cold and Hot Deserts, eds. L. Schultz et al., Lun.Plan.Inst.Tech.Rep. 95-02, Houston, Texas). Jull A.J.T. et al. (1990) Distribution of terrestrial age and petrologic type of meteorites from western Libya (GCA 54, 2895-2898). Jull A.J.T. et al. (1991) Terrestrial ages and petrologic description of Roosevelt County meteorites (abs. Lun.Plan. Sci. 22, 667-668). Jull A.J.T. et al. (1993) 14C terrestrial ages of meteorites from desert regions: Algeria and Australia (abs. Meteoritics 28-3, 1993, 376). Jull A.J.T. et al. (2002) Terrestrial ages of some meteorites from Oman (MAPS 37-7, 2002, A074). P.A. Bland et al. (1995) Weathering of ordinary chondrites from Algeria and Australia as a climatic indicator (abs. Meteoritics 30-5, 1995, 487). Schultz L. et al. (1998) Ten new meteorites from the Ténéré Desert (Niger): Classification, noble gases, cosmogenic radionuclides, and terrestrial ages (Meteoritics 33-4, 1998, A138). Al-Kathiri A. et al. (2005) Weathering of meteorites from Oman: Correlation of chemical and mineralogical weathering proxies with 14C terrestrial ages and the influence of soil chemistry (Meteoritics 40-8, 2005, pp. 1215-1239). Welten K.C. et al. (2004) Exposure history and terrestrial ages of ordinary chondrites from the Dar al Gani region, Libya (MAPS 39-3, 2004, 481-498). Stelzner Th. et al. (1996) The study of weathering products of meteorites by means of evolved gas analysis (Meteoritics 31-2, 1996, 249-254). Cheers, Bernd __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica)
50% is not even close. I counted the peer-reviewed papers in the 2012 volume of MAPS. In the 58 non-review papers that reported analyses of physical samples of meteorites, 52% used falls, 12% used non-desert finds, 24% used hot desert meteorites, and 28% used Antarctic meteorites. (this sums to 100% because some papers reported data in multiple categories). So, if 2012 in MAPS is representative (I'm done counting, so I can't answer that), when it comes to the question of what are the most important meteorites for Science these days, it isn't hot OR cold desert meteorites... it's observed falls. Papers on hot and cold desert meteorites are subequal, which is the trend we all see. Jeff On 10/10/2013 12:27 AM, Adam Hupe wrote: I will not debate the legacy of Antarctic meteorites. They have had a wonderful history and their contribution to science has been invaluable. Most researchers are sample oriented and are not biased by find location but there are still a few that cling to legacy. Antarctica had a a two decade plus head start in the abstract/paper queue so naturally there are more documents. Ten years ago, maybe one in ten papers were on hot desert finds. Now, I estimate about 50%. At this rate, as very important samples from NWA and other deserts enter the queue, it will not be long before these finds handily overtake Antarctica by a wide margin in the business of science. In other words; There is not enough material coming out of Antarctica anymore to reverse the current trend which favors the hot desert meteorites for research material in the future. Adam __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica)
Jeff Stated: Papers on hot and cold desert meteorites are subequal, which is the trend we all see. I agree with this statement. They were not subequal just a few years ago meaning the trend is favoring hot desert finds long term. The number of rare and unusual meteorites coming out of the hot deserts far exceed those being recovered from Antarctica. Adam --- Original Message - From: Jeff Grossman jngross...@gmail.com To: meteorite-list@meteoritecentral.com Cc: Sent: Thursday, October 10, 2013 6:03 AM Subject: Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica) 50% is not even close. I counted the peer-reviewed papers in the 2012 volume of MAPS. In the 58 non-review papers that reported analyses of physical samples of meteorites, 52% used falls, 12% used non-desert finds, 24% used hot desert meteorites, and 28% used Antarctic meteorites. (this sums to 100% because some papers reported data in multiple categories). So, if 2012 in MAPS is representative (I'm done counting, so I can't answer that), when it comes to the question of what are the most important meteorites for Science these days, it isn't hot OR cold desert meteorites... it's observed falls. Papers on hot and cold desert meteorites are subequal, which is the trend we all see. Jeff On 10/10/2013 12:27 AM, Adam Hupe wrote: I will not debate the legacy of Antarctic meteorites. They have had a wonderful history and their contribution to science has been invaluable. Most researchers are sample oriented and are not biased by find location but there are still a few that cling to legacy. Antarctica had a a two decade plus head start in the abstract/paper queue so naturally there are more documents. Ten years ago, maybe one in ten papers were on hot desert finds. Now, I estimate about 50%. At this rate, as very important samples from NWA and other deserts enter the queue, it will not be long before these finds handily overtake Antarctica by a wide margin in the business of science. In other words; There is not enough material coming out of Antarctica anymore to reverse the current trend which favors the hot desert meteorites for research material in the future. Adam __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica)
Hi all, Just a thought. Don't know if it has been mentioned in this thread, but I wonder how many Falls have been reported out of the Antartic and what importance would the actual sighting of a meteor and it's recovery hold to the science and importance of the specimen? I can think of one for suretime of arrival! Cordially, Count Deiro IMCA 3536 MetSoc -Original Message- From: Adam Hupe raremeteori...@yahoo.com Sent: Oct 9, 2013 9:27 PM To: Adam meteorite-list@meteoritecentral.com Subject: Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica) I will not debate the legacy of Antarctic meteorites. They have had a wonderful history and their contribution to science has been invaluable. Most researchers are sample oriented and are not biased by find location but there are still a few that cling to legacy. Antarctica had a a two decade plus head start in the abstract/paper queue so naturally there are more documents. Ten years ago, maybe one in ten papers were on hot desert finds. Now, I estimate about 50%. At this rate, as very important samples from NWA and other deserts enter the queue, it will not be long before these finds handily overtake Antarctica by a wide margin in the business of science. In other words; There is not enough material coming out of Antarctica anymore to reverse the current trend which favors the hot desert meteorites for research material in the future. Adam __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica)
I think where NWA and the hot desert finds have had the greatest benefit to science with a capital S are in achondrites and in particular martian meteorites. If you look at the abstracts at 2012-2013 LPSC and MetSoc (no, I didn't actually count them) the martian meteorite literature is now dominated by NWA finds and Tissint. Again, ANSMET just isn't nearly as productive, and you can have multi-year dry spells when no ANSMET martians were recovered. Recently it has been very sparse with 1 pairing in 2012, 1 pairing in 2009, 1 find in 2006. In fact, according to MetBull, in the last ten years there have been only 6 martians (12, not counting pairings) recovered. Another ANSMET martian drought was 1994-2000. Lunars in NWA are productive too, but interestingly dominated by feldspathic breccias. For lunars though, at least for the foreseeable future, there will never be a contest for dominance because of the 390 kg of Moon rocks from Apollo, which will be the gold standard until we return to the Moon. In contrast, a Mars sample return seems to always be 10 years away with a continually out-of-reach horizon. So martian meteorites, mostly from NWA, will be our Mars sample return until we get a President who tells NASA to go to Mars with MSR or humans (or until Chinese beat us to it). Carl * Carl B. Agee Director and Curator, Institute of Meteoritics Professor, Earth and Planetary Sciences MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 Tel: (505) 750-7172 Fax: (505) 277-3577 Email: a...@unm.edu http://meteorite.unm.edu/people/carl_agee/ On Thu, Oct 10, 2013 at 7:54 AM, Adam Hupe raremeteori...@yahoo.com wrote: Jeff Stated: Papers on hot and cold desert meteorites are subequal, which is the trend we all see. I agree with this statement. They were not subequal just a few years ago meaning the trend is favoring hot desert finds long term. The number of rare and unusual meteorites coming out of the hot deserts far exceed those being recovered from Antarctica. Adam --- Original Message - From: Jeff Grossman jngross...@gmail.com To: meteorite-list@meteoritecentral.com Cc: Sent: Thursday, October 10, 2013 6:03 AM Subject: Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica) 50% is not even close. I counted the peer-reviewed papers in the 2012 volume of MAPS. In the 58 non-review papers that reported analyses of physical samples of meteorites, 52% used falls, 12% used non-desert finds, 24% used hot desert meteorites, and 28% used Antarctic meteorites. (this sums to 100% because some papers reported data in multiple categories). So, if 2012 in MAPS is representative (I'm done counting, so I can't answer that), when it comes to the question of what are the most important meteorites for Science these days, it isn't hot OR cold desert meteorites... it's observed falls. Papers on hot and cold desert meteorites are subequal, which is the trend we all see. Jeff On 10/10/2013 12:27 AM, Adam Hupe wrote: I will not debate the legacy of Antarctic meteorites. They have had a wonderful history and their contribution to science has been invaluable. Most researchers are sample oriented and are not biased by find location but there are still a few that cling to legacy. Antarctica had a a two decade plus head start in the abstract/paper queue so naturally there are more documents. Ten years ago, maybe one in ten papers were on hot desert finds. Now, I estimate about 50%. At this rate, as very important samples from NWA and other deserts enter the queue, it will not be long before these finds handily overtake Antarctica by a wide margin in the business of science. In other words; There is not enough material coming out of Antarctica anymore to reverse the current trend which favors the hot desert meteorites for research material in the future. Adam __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica)
Carl Stated For lunars though, at least for the foreseeable future, there will never be a contest for dominance because of the 390 kg of Moon rocks from Apollo, which will be the gold standard until we return to the Moon. I agree that the Apollo returned Moon rocks are a national treasure. One of the highlights of my life was seeing some of these specimens for myself up close and personal in the Lunar Receiving Laboratory (Vault) at the NASA facility at the Lyndon B. Johnson Space Center where this precious material is stored. Where lunar finds contribute to science is that many have come from unsampled parts of the Moon. There are a few unique Lunaite examples that provide additional understanding of our nearest celestial neighbor. I was pleased to see a poster of NWA 5000 on the wall right across the hall from the NASA Moon rock vault. This tells me that the researches are sample oriented and where a Moon rock comes from is secondary. This enhances data acquisition instead of competing against it. Adam - Original Message - From: Carl Agee a...@unm.edu To: Adam Hupe raremeteori...@yahoo.com Cc: Adam meteorite-list@meteoritecentral.com Sent: Thursday, October 10, 2013 9:35 AM Subject: Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica) I think where NWA and the hot desert finds have had the greatest benefit to science with a capital S are in achondrites and in particular martian meteorites. If you look at the abstracts at 2012-2013 LPSC and MetSoc (no, I didn't actually count them) the martian meteorite literature is now dominated by NWA finds and Tissint. Again, ANSMET just isn't nearly as productive, and you can have multi-year dry spells when no ANSMET martians were recovered. Recently it has been very sparse with 1 pairing in 2012, 1 pairing in 2009, 1 find in 2006. In fact, according to MetBull, in the last ten years there have been only 6 martians (12, not counting pairings) recovered. Another ANSMET martian drought was 1994-2000. Lunars in NWA are productive too, but interestingly dominated by feldspathic breccias. For lunars though, at least for the foreseeable future, there will never be a contest for dominance because of the 390 kg of Moon rocks from Apollo, which will be the gold standard until we return to the Moon. In contrast, a Mars sample return seems to always be 10 years away with a continually out-of-reach horizon. So martian meteorites, mostly from NWA, will be our Mars sample return until we get a President who tells NASA to go to Mars with MSR or humans (or until Chinese beat us to it). Carl * Carl B. Agee Director and Curator, Institute of Meteoritics Professor, Earth and Planetary Sciences MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 Tel: (505) 750-7172 Fax: (505) 277-3577 Email: a...@unm.edu http://meteorite.unm.edu/people/carl_agee/ On Thu, Oct 10, 2013 at 7:54 AM, Adam Hupe raremeteori...@yahoo.com wrote: Jeff Stated: Papers on hot and cold desert meteorites are subequal, which is the trend we all see. I agree with this statement. They were not subequal just a few years ago meaning the trend is favoring hot desert finds long term. The number of rare and unusual meteorites coming out of the hot deserts far exceed those being recovered from Antarctica. Adam --- Original Message - From: Jeff Grossman jngross...@gmail.com To: meteorite-list@meteoritecentral.com Cc: Sent: Thursday, October 10, 2013 6:03 AM Subject: Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica) 50% is not even close. I counted the peer-reviewed papers in the 2012 volume of MAPS. In the 58 non-review papers that reported analyses of physical samples of meteorites, 52% used falls, 12% used non-desert finds, 24% used hot desert meteorites, and 28% used Antarctic meteorites. (this sums to 100% because some papers reported data in multiple categories). So, if 2012 in MAPS is representative (I'm done counting, so I can't answer that), when it comes to the question of what are the most important meteorites for Science these days, it isn't hot OR cold desert meteorites... it's observed falls. Papers on hot and cold desert meteorites are subequal, which is the trend we all see. Jeff On 10/10/2013 12:27 AM, Adam Hupe wrote: I will not debate the legacy of Antarctic meteorites. They have had a wonderful history and their contribution to science has been invaluable. Most researchers are sample oriented and are not biased by find location but there are still a few that cling to legacy. Antarctica had a a two decade plus head start in the abstract/paper queue so naturally there are more documents. Ten years ago, maybe one in ten papers were on hot desert finds. Now, I estimate about 50%. At this rate, as very important samples from NWA and other deserts enter the queue, it will not be long
Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica)
Adam, I totally agree! And actually the lunar meteorites are telling us that the Apollo collection is highly skewed towards the mare basalts and other possibly atypical rocks of the nearside. Now if we could just prove that a particular lunar meteorite was a sample from the South Pole Aitken Basin! Carl * Carl B. Agee Director and Curator, Institute of Meteoritics Professor, Earth and Planetary Sciences MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 Tel: (505) 750-7172 Fax: (505) 277-3577 Email: a...@unm.edu http://meteorite.unm.edu/people/carl_agee/ On Thu, Oct 10, 2013 at 11:22 AM, Adam Hupe raremeteori...@yahoo.com wrote: Carl Stated For lunars though, at least for the foreseeable future, there will never be a contest for dominance because of the 390 kg of Moon rocks from Apollo, which will be the gold standard until we return to the Moon. I agree that the Apollo returned Moon rocks are a national treasure. One of the highlights of my life was seeing some of these specimens for myself up close and personal in the Lunar Receiving Laboratory (Vault) at the NASA facility at the Lyndon B. Johnson Space Center where this precious material is stored. Where lunar finds contribute to science is that many have come from unsampled parts of the Moon. There are a few unique Lunaite examples that provide additional understanding of our nearest celestial neighbor. I was pleased to see a poster of NWA 5000 on the wall right across the hall from the NASA Moon rock vault. This tells me that the researches are sample oriented and where a Moon rock comes from is secondary. This enhances data acquisition instead of competing against it. Adam - Original Message - From: Carl Agee a...@unm.edu To: Adam Hupe raremeteori...@yahoo.com Cc: Adam meteorite-list@meteoritecentral.com Sent: Thursday, October 10, 2013 9:35 AM Subject: Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica) I think where NWA and the hot desert finds have had the greatest benefit to science with a capital S are in achondrites and in particular martian meteorites. If you look at the abstracts at 2012-2013 LPSC and MetSoc (no, I didn't actually count them) the martian meteorite literature is now dominated by NWA finds and Tissint. Again, ANSMET just isn't nearly as productive, and you can have multi-year dry spells when no ANSMET martians were recovered. Recently it has been very sparse with 1 pairing in 2012, 1 pairing in 2009, 1 find in 2006. In fact, according to MetBull, in the last ten years there have been only 6 martians (12, not counting pairings) recovered. Another ANSMET martian drought was 1994-2000. Lunars in NWA are productive too, but interestingly dominated by feldspathic breccias. For lunars though, at least for the foreseeable future, there will never be a contest for dominance because of the 390 kg of Moon rocks from Apollo, which will be the gold standard until we return to the Moon. In contrast, a Mars sample return seems to always be 10 years away with a continually out-of-reach horizon. So martian meteorites, mostly from NWA, will be our Mars sample return until we get a President who tells NASA to go to Mars with MSR or humans (or until Chinese beat us to it). Carl * Carl B. Agee Director and Curator, Institute of Meteoritics Professor, Earth and Planetary Sciences MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 Tel: (505) 750-7172 Fax: (505) 277-3577 Email: a...@unm.edu http://meteorite.unm.edu/people/carl_agee/ On Thu, Oct 10, 2013 at 7:54 AM, Adam Hupe raremeteori...@yahoo.com wrote: Jeff Stated: Papers on hot and cold desert meteorites are subequal, which is the trend we all see. I agree with this statement. They were not subequal just a few years ago meaning the trend is favoring hot desert finds long term. The number of rare and unusual meteorites coming out of the hot deserts far exceed those being recovered from Antarctica. Adam --- Original Message - From: Jeff Grossman jngross...@gmail.com To: meteorite-list@meteoritecentral.com Cc: Sent: Thursday, October 10, 2013 6:03 AM Subject: Re: [meteorite-list] Exploring the Solar System in Antarctica (NWA vs Antarctica) 50% is not even close. I counted the peer-reviewed papers in the 2012 volume of MAPS. In the 58 non-review papers that reported analyses of physical samples of meteorites, 52% used falls, 12% used non-desert finds, 24% used hot desert meteorites, and 28% used Antarctic meteorites. (this sums to 100% because some papers reported data in multiple categories). So, if 2012 in MAPS is representative (I'm done counting, so I can't answer that), when it comes to the question of what are the most important meteorites for Science these days, it isn't hot OR cold desert meteorites... it's
[meteorite-list] Sundiving Comet, Juno Photographed
Space Weather News for Oct. 10, 2013 http://spaceweather.com SUNDIVING COMET: A comet is falling into the sun today. Images from the Solar and Heliospheric Observatory show a bright comet rapidly evaporating as the sun turns up the heat, and it may be only hours away from complete disintegration. Check http://spaceweather.com for images of the death plunge. JUNO PHOTOGRAPHED: Yesterday, NASA's Juno spacecraft buzzed Earth only 347 miles above our planet's surface. Although the spacecraft was very faint, several amateur astronomers managed to photograph it. Their images are featured in a special gallery on today's edition of http://spaceweather.com. __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Martian Scars (Mars Express)
http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Martian_scars Martian scars European Space Agency 10 October 2013 Ripped apart by tectonic forces, Hebes Chasma and its neighbouring network of canyons bear the scars of the Red Planet's early history. ESA's Mars Express has flown over this region of Mars on numerous occasions, but this new eight-image mosaic reveals Hebes Chasma in full and in greater detail than ever (click image for full mosaic). [Image] Hebes Chasma in context Hebes Chasma is an enclosed, almost 8 km-deep trough stretching 315 km in an east-west direction and 125 km from north to south at its widest point. It sits about 300 km north of the vast Valles Marineris canyon complex. The origin of Hebes Chasma and neighbouring canyons is associated with the nearby volcanic Tharsis Region, home to the largest volcano in the Solar System, Olympus Mons. [Image] Hebes Chasma topography As the Tharsis bulge swelled with magma during the planet's first billion years, the surrounding crust was stretched, eventually ripping apart and collapsing into gigantic troughs, including Hebes Chasma. Intricate fault patterns can be seen all around the deep depression - they are especially evident in the main colour and 3D images. In the centre of Hebes Chasma, there is a flat-topped mesa that rises to level similar to that of the surrounding plains. It is shown from different angles in the two perspective images below. No other canyon on Mars has a similar feature and its origin is not entirely clear. Its layers include volcanic materials - just like in the main canyon walls - but also wind-blow dust and lake sediments that were laid down over time. A horseshoe-shaped chunk has been taken out of one side of the mesa, seen below, where material has slumped down onto the valley floor below. [Image] Hebes Chasma in 3D A landslide may also be responsible for the dark patch in this image, which appears to pool like spilt ink across the debris. It is most likely loose dust that has slid down the walls, perhaps helped along where melting ice or ground-water weakened the rocks to create a flow-like feature. A similar feature is visible at the opposite end of the mound, as seen in the full-colour image. Other landslide deposits are seen all over the floor of Hebes Chasma, many coming from the main canyon walls. Numerous grooves are etched into both the canyon walls and the mesa, suggesting the material is weak and easily eroded. [Image] Landslides and rock layers inside Hebes Chasma In the second perspective view above, a thin band of darker material is seen between two layers of light material. One idea is that the material was blown or slid from the top of the mound and collected on the slopes below. Dark material is also seen around the base of the mesa, which either eroded away from the younger sediment layers located higher up in the mesa, or were deposited separately by wind or water. Other layers revealed in the sides of the mesa may also have been deposited by water. Data from both Mars Express and NASA's Mars Reconnaissance Orbiter reveal that some parts of Hebes Chasma are laced with minerals that can form only in the presence of water, suggesting that at some point in the Red Planet's history the canyon might have been filled with a lake. However, it is apparent from the chaotic debris that fills the canyon floor that enormous landslides have also played a key role in shaping and widening this deep scar since its formation. [Image] Hebes Chasma in 3D __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Telescopes Large and Small Team Up to Study Triple Asteroid 87 Sylvia
http://www.seti.org/seti-institute/press-release/telescopes-large-and-small-team-study-triple-asteroid Telescopes Large and Small Team Up to Study Triple Asteroid SETI Institute October 7, 2013 Combining observations from the world's largest telescopes with small telescopes used by amateur astronomers, a team of astronomers discovered that the large main-belt asteroid (87) Sylvia has a complex interior, probably linked to the way the multiple system was formed. The findings are being revealed today at the 45^th annual Division of Planetary Sciences meeting in Denver, Colorado. This work illustrates a new trend in astronomy in which backyard amateur astronomers team up with professional astronomers to expand our knowledge of our solar system. The study of multiple asteroids such as (87) Sylvia gives astronomers an opportunity to peek through the past history of our solar system and constrain the internal composition of asteroids. In 2005, the triple asteroid was discovered to possess two moons. The team, led by Franck Marchis, senior research scientist at the Carl Sagan Center of the SETI Institute, has continued to observe this triple asteroid system by gathering 66 adaptive optics observations from 8-10m class telescopes including those at the W. M. Keck Observatory, the European Southern Observatory, and Gemini North. Because (87) Sylvia is a large, bright asteroid located in the main belt, it is a great target for the first generation of adaptive optics systems available on these large telescopes. We have combined data from our team with archival data to get a good understanding of the orbits of these moons, Marchis said. With expert assistance from colleagues at the Institut de Mecanique Celeste et de Calcul des Ephemerides (IMCCE) of the Observatoire de Paris, the team developed an accurate dynamical model of the system, allowing them to predict the position of the moons around the asteroid at any time. The drop test of this work was the prediction of the relative positions of the moons during an occultation on Jan. 6, 2013. Observers equipped with small telescopes located on a narrow path across the south of France, Italy and Greece could see the triple system (87) Sylvia passing in front of a bright 11-mag star. Such occultations allow exquisitely precise measurements of the relative positions and sizes of the occulting objects. In collaboration with EURASTER, a group of amateur and professional astronomers, the team successfully motivated ~50 observers to watch the event. Twelve of them detected the occultation by the primary of the system which lasted between 4 and 10 seconds depending on the observer's position on Earth. Additionally, four observers detected a two-second eclipse of the star caused by Romulus, the outermost satellite, at a relative position close to our prediction. This result confirmed the accuracy of our model and provided a rare opportunity to directly measure the size and shape of the satellite, Jerome Berthier, astronomer at IMCCE said. The chords of this occultation observations revealed that Romulus is 24 km in diameter with an extremely elongated shape, possibly made of two lobes joined together like a dumbbell. This is not surprising if the satellite formed from the accretion of fragments created by the disruption of a proto-Sylvia by an impact, several billion years ago. The team derived the shape of the 270-km primary asteroid Sylvia by combining data from the occultation of the asteroid with other sources of information. These included archived recordings of the variation of light caused by the spin of the asteroid, and direct imaging by adaptive optics systems. Because the satellites' orbits do not seem to be affected by the irregular shape of the asteroid, the team concluded that the large asteroid is most likely differentiated. The asteroid likely has a spherical core of dense material, surrounded by a fluffy or fractured outer surface layer. Combined observations from small and large telescopes provide a unique opportunity to understand the nature of this complex and enigmatic triple asteroid system, Marchis said. Thanks to the presence of these moons, we can constrain the density and interior of an asteroid, without the need for a spacecraft's visit. Knowledge of the internal structure of asteroids is key to understanding how the planets of our solar system formed. Support for this work was provided by NASA through grant number NNX11AD62G. __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Archival Hubble Images Reveal Neptune's Lost Inner Moon, Naiad
http://www.seti.org/seti-institute/press-release/archival-hubble-images-reveal-neptunes-lost-inner-moon Archival Hubble Images Reveal Neptune's Lost Inner Moon, Naiad SETI Institute October 8, 2013 Neptune's tiny, innermost moon, Naiad, has now been seen for the first time since it was discovered by Voyager's cameras in 1989. Dr. Mark Showalter, a senior research scientist at the SETI Institute in Mountain View, California, announced the result today in Denver, Colorado, at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society. He and collaborators Dr. Jack Lissauer of the NASA Ames Research Center, Dr. Imke de Pater of UC Berkeley, and Robert French of the SETI Institute, also released a dramatic new image of Neptune's puzzling rings and ring-arcs, which were first imaged by Voyager. Naiad has been an elusive target ever since Voyager left the Neptune system, said Dr. Showalter. From Earth, Neptune is 2 million times brighter than Naiad, andthetwo are separated by only one arcsecond. This is equivalent to the width of a human hair from 50 feet away, noted collaborator Lissauer. The team of astronomers needed to develop new techniques to suppress Neptune's glare. Naiad was finally revealed, moving across a sequence of eight images taken during December 2004. Strangely, Naiad appears to have veered significantly off course. The astronomers are puzzled by the fact that Naiad is now far ahead of its predicted orbital position. They wonder whether gravitational interactions with one of Neptune's other moons may have caused it to speed up, although the details remain mysterious. Further observations will be needed in order to understand Naiad's motion. In addition to its moons, Neptune hosts a family faint rings and ring-arcs. The arcs have been changing slowly in the years since their discovery. Whereas Voyager saw a set of four closely-spaced arcs, the leading two arcs have been fading away, and are completely absent from the newest images. The trailing arcs, however, are essentially unchanged. This system of arcs is probably confined by the gravitational effects of the nearby moon Galatea, but the reason for the long-term changes is unknown. Dr. de Pater has also been following the ongoing evolution of the arcs from the 10-meter W. M. Keck telescope in Hawaii. Showalter and his collaborators had previously announced the discovery of a tiny moon of Neptune in July. That moon, which is no more than 20 km (12 miles) across, goes by the provisional designation S/2004 N 1. The new results reported today are based on further analysis of the same images, which were all obtained by Hubble between 2004 and 2009. Although 100-km Naiad is much larger than the moon announced in July, it orbits much closer to Neptune and so has proven to be much harder to detect. It is always exciting to find new results in old data, Showalter remarked. We keep discovering new ways to push the limit of what information can be gleaned from Hubble's vast collection of planetary images. Support for this work was provided by NASA through grant number from the SPACE TELESCOPE SCIENCE INSTITUTE, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Sundiving Comet, Juno Photographed
Hi Ron, In addition, within minutes of the sun-diving Kreutz comet's closest approach to the sun, a large coronal mass ejection (CME) erupted from the sun's southern hemisphere in what appears to be about the same direction from which the comet came. Solar scientists have pretty much put to rest the notion that there is any mechanism by which one of these tiny sungrazing comets could trigger a CME. That said, you would have to agree that the location and timing (CME starts at around 15:36 UT on 10 October as seen in the narrow LASCO C2 field of view) of this latest CME relative to the comet's perihelion is pretty coincidental. Two years ago I carried out a statistical analysis of all Kreutz comets in 2009 (the last year for which sungrazing comet perihelion date information was available at that time) against all the CMEs from that year. Here's what I found: # of comets: 142 # of CMEs: 746 Average time between CMEs: 11.71 hours Of the 142 comets, 57 (40%) had perihelions within +/- 3 hours of a CME, which is not statistically significant. 26 comets (18%) had perihelions within +/- 1 hour of a CME -- about what one would expect from random chance. However, 17 comets (12%) had perihelions within +/- 30 minutes of a CME. This ~is~ about 5 more comets than one would expect from chance, but it could still just be a random fluke given the small sample size. But events like today's do rekindle my interest in trying to prove one way or the other whether these recurring correlations go beyond mathematical chance. --Rob -Original Message- From: meteorite-list-boun...@meteoritecentral.com [mailto:meteorite-list-boun...@meteoritecentral.com] On Behalf Of Ron Baalke Sent: Thursday, October 10, 2013 1:14 PM To: Meteorite Mailing List Subject: [meteorite-list] Sundiving Comet, Juno Photographed Space Weather News for Oct. 10, 2013 http://spaceweather.com SUNDIVING COMET: A comet is falling into the sun today. Images from the Solar and Heliospheric Observatory show a bright comet rapidly evaporating as the sun turns up the heat, and it may be only hours away from complete disintegration. Check http://spaceweather.com for images of the death plunge. JUNO PHOTOGRAPHED: Yesterday, NASA's Juno spacecraft buzzed Earth only 347 miles above our planet's surface. Although the spacecraft was very faint, several amateur astronomers managed to photograph it. Their images are featured in a special gallery on today's edition of http://spaceweather.com. __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Comet C/ISON Details Emerge as it Races Toward the Sun
http://www.psi.edu/news/ISON3.html Comet C/ISON Details Emerge as it Races Toward the Sun Planetary Science Institute Oct. 9, 2013 Tucson, Ariz. -- Scientists are unraveling more information on Comet C/2012 S1 (ISON) as it continues on its journey toward the Sun. Comet C/ISON will skim 730,000 miles above the Sun's surface on Nov. 28 and has the potential to be readily visible from Earth starting in early December. We measured the rotational pole of the nucleus. The pole indicates that only one side of the comet is being heated by the Sun on its way in until approximately one week before it reaches it closest point to the Sun, said Planetary Science Institute Research Scientist Jian-Yang Li, who led a team that imaged the comet. Since the surface on the dark side of the comet should still retain a large fraction of very volatile materials, the sudden exposure to the strong sunlight when it gets closer to the Sun than Mercury could trigger huge outbursts of material, Li said. Li presented the findings today at the American Astronomical Society's Division for Planetary Sciences 45th Annual Meeting in Denver. Comet C/ISON was imaged with the Hubble Space Telescope using the Wide Field Camera 3 on April 10. We measured the color of the coma, and found that the outer part of the coma is slightly redder than the inner part, Li said. This color change is unusual in comets, and seems to imply that the inner part contains some water ice grains, which sublimate as they move away from the nucleus. Comet C/ISON was discovered in September 2012 when it was farther away from the Sun than Jupiter, and was already active at such a great distance. This is distinct from most other sungrazers - comets that pass extremely close to the sun - that are only discovered and remain visible for at most several days when nearest the Sun. At such a close perihelion distance from the Sun, sungrazers are expected to be intensely heated by the Sun, and sublimate not only ice but also silicates and even metals, releasing a tremendous amount of dust. The expectation is high that Comet C/ISON will be much brighter and more spectacular than most other sungrazers when it puts on a show late this year. As a first-time visitor to the inner solar system, Comet C/ISON provides astronomers a rare opportunity to study a fresh comet preserved since the formation of the Solar System, Li said. The expected high brightness of the comet as it nears the Sun allows for many important measurements that are impossible for most other fresh comets. NASA and the Space Telescope Science Institute funded the project. __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] SwRI Study Finds That Pluto Satellites' Orbit Ballet May Hint of Long-Ago Collisions
http://www.swri.org/9what/releases/2013/pluto-moon.htm SwRI study finds that Pluto satellites' orbital ballet may hint of long-ago collisions Southwest Research Institute Embargoed for release at 1 p.m. CDT on Wednesday, Oct. 9, 2013 Boulder, Colo. - Oct. 9, 2013 - A large impact 4 billion years ago may account for the puzzling orbital configuration among Pluto's five known satellites, according to a new model developed by planetary scientists from Southwest Research Institute (SwRI). Starting with Charon, Pluto's nearest and largest moon, each of the successively more distant - and much smaller - moons orbits Pluto according to a steadily increasing factor of Charon's own orbital period. The small satellites, Styx, Nix, Kereberos and Hydra, have orbital periods that are almost exactly 3, 4, 5 and 6 times longer than Charon's. Their distance from Pluto and the orbital arrangement of the satellites has been a challenge for theories of the small satellites' formation, said lead investigator Dr. Harold Hal Levison, an Institute scientist in SwRI's Planetary Science Directorate at Boulder, Colo. Models for the formation of Charon leave plenty of small satellites, but all of them are much closer to Pluto than the current system that we see today,' said Levison. A major problem has been understanding how to move these satellites outward, but not lose them from the Pluto-Charon system or have them crash into Charon. He said, 'This configuration suggests that we have been missing some important mechanism to transport material around in this system. The SwRI study, funded by a grant from NASA's Outer Planetary Research program and Lunar Science Institute, considered the earliest and most dynamic epoch of the Pluto/Charon system. It is thought that Charon was formed by a large impact during a period in solar system history when such collisions were dramatically more frequent. Any initially surviving satellites would likely be destroyed in collisions, but these shattered moons wouldn't be lost; rather, their remains would stay in the Pluto/Charon system and become the starting point for building new satellites. Thus there would have been many generations of satellite systems over the history of Pluto and Charon. In modeling the destruction of the satellites, the SwRI study found that there may be a method for moving them, or their building blocks, outward, due to the competing effects of Charon's gravitational kicks and collisions among the debris of the disrupted satellites. Charon is the largest satellite of any planet or dwarf-planet, weighing in at 1/10 the mass of Pluto (the Moon is just 1/81 the mass of Earth), and so it could rapidly slingshot the small satellites outward if they were to approach too closely. Meanwhile, collisions among small satellites can change orbits to keep things away from Charon. When combined, this leads to a series of satellites colliding, breaking to pieces, moving outward and then rebuilding. The implications for this result are that the current small satellites are the last generation of many previous generations of satellites, said Dr. Kevin Walsh, another investigator and a research scientist in SwRI's Planetary Science Directorate at Boulder, Colo. They were probably first formed around 4 billion years ago, and after an eventful million years of breaking and rebuilding, have survived in their current configuration ever since. This work used the Extreme Science and Engineering Discovery Environment (XSEDE) digital collection, which is supported by National Science Foundation grant number OCI-1053575. __ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Watery Asteroid Discovered in Dying Star Points to Habitable Exoplanets
http://www.keckobservatory.org/recent/entry/watery_asteroid_discovered_in_dying_star_points_to_habitable_exoplanets Watery Asteroid Discovered in Dying Star Points to Habitable Exoplanets W. M. Keck Observatory October 10, 2013 Kamuela, HI -- Astronomers have found the shattered remains of an asteroid that contained huge amounts of water orbiting an exhausted star, or white dwarf. This suggests that the star GD 61 and its planetary system - located about 150 light years away and at the end of its life - had the potential to contain Earth-like exoplanets. The new research findings used data collected from NASA's Hubble Space Telescope, both of W. M. Keck Observatory's Keck I and Keck II telescopes, as well NASA's FUSE telescope, and are reported today in the journal Science. This is the first time both water and a rocky surface - two key ingredients for habitable planets - have been found together beyond our solar system. Earth is essentially a dry planet, with only 0.02% of its mass as surface water, meaning oceans came long after it had formed; most likely when water-rich asteroids in the solar system crashed into our planet. The asteroid analyzed is composed of 26% water mass, very similar to Ceres, the largest asteroid in the main belt of our solar system. Both are vastly more water-rich compared with Earth. The new discovery shows the same water delivery system could have occurred in this distant, dying star's solar system - as latest evidence points to it containing a similar type of water-rich asteroid that would have first brought water to Earth. Astronomers at the Universities of Cambridge and Warwick say this is the first reliable evidence' for water-rich, rocky planetary material in any extrasolar planetary system. The scientists, led by Cambridge's Institute of Astronomy's Jay Farihi, describe it as a look into our future. Six billion years from now, alien astronomers studying the rocky remains around our burned out sun might reach the same conclusion: terrestrial planets once circled our parent star. All rocky planets form from the accumulation of asteroids, growing until full size, so asteroids are essentially the 'building blocks' of planets. The finding of water in a large asteroid means the building blocks of habitable planets existed - and maybe still exist - in the GD 61 system, and likely also around a substantial number of similar parent stars, Farihi said. These water-rich building blocks, and the terrestrial planets they build, may in fact be common - a system cannot create things as big as asteroids and avoid building planets, and GD 61 had the ingredients to deliver lots of water to their surfaces, Farihi said. Our results demonstrate that there was definitely potential for habitable planets in this exoplanetary system. The detected water most likely came from a minor planet, at least 90 km in diameter but probably much larger, that once orbited the GD 61 star before it became a white dwarf around 200 million years ago. Previous and current astronomical observations have measured the size and density of exoplanets, but not their composition, because conventional work was only done on planets orbiting living stars. But the only way to see what a distant planet is made of is to take it apart, say the researchers, and nature does this in a dying white dwarf system through its extreme gravitational pull - sucking in and shredding the surrounding material. This debris was chemically analyzed using powerful spectrograph instruments installed on the Keck I and Keck II telescopes to detect a range of elemental abundances in the white dwarf's contaminated atmosphere, including magnesium, silicon and iron, which, together with oxygen are the main components of rocks. By calculating the number of these elements relative to oxygen, the researchers were able to predict how much oxygen should be in the atmosphere of the white dwarf - but they found significantly more oxygen than if there were only rocks. This oxygen excess can be carried by either water or carbon, and in this star there is virtually no carbon - indicating there must have been substantial water, said co-author Boris Gänsicke, from the University of Warwick. This also rules out comets, which are rich in both water and carbon compounds, so we knew we were looking at a rocky asteroid with substantial water content - perhaps in the form of subsurface ice - like the asteroids we know in our solar system such as Ceres, Gänsicke said. The team used the Cosmic Origins Spectrograph onboard Hubble to obtain precise oxygen levels in the white dwarf's debris, with chemical analysis computed by team member Detlev Koester from the University of Kiel. The planetary bodies such as these asteroids that fall into and pollute this dying star - which, in its heyday, was three times heavier than our sun - also reveal that giant exoplanets probably still exist in
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