Ronn!Blankenship wrote: > >> Ok, so we can assume that the Sun will keep its current orbit around >> the Galaxy. But what about other stars? > > Then you could always do what you do to extrapolate solar system > positions: start with the current positions and velocities of all the > stars for which you have data, compute the gravitational forces between > each pair of stars, then do a stepwise integration. (Of course, you do > have access to large blocks of time on a Cray, don't you?) > :-)))))))))
No, but I guess I have some quite weird ideas that I _could_ use if I needed to do that > And you'll need > to approximate the general gravitational field of the galaxy as a > whole. For a description of that, as well as the kind of orbits stars > follow in the galactic gravitational field, probably the standard text > Ok, I will take a look at them when I am (allegedly) working O:-) [anything that has any semblance to orbital dynamics is fair game in my job] > >However, I suspect that over the time periods you're talking about (a few >x10^6 years), there will be at most only a few close enough encounters >between stars to significantly affect the paths of the stars. Stars are >really w—i—d—e—ly separated in our neighborhood of the galaxy. (You are >not concerned with the stars in the central regions of a globular cluster >or near Sgr A*, which are about the only places they are really crowded . . . ) > Unless I am trying to identify Trantor :-) BTW, is Proxima gravitationally bound with Alfa Centauri A and B? On a tangential note, the Jijo books mention that Izmunuti is 1 light-year away from Jijo-S [whose name is Ganjoo - I guess]. Is it possible that they can keep such a long distance for millions of years? I don't think they can be gravitationally bound that far > >Actually, the "Celestia 2000" program mentioned there fits on a CD-ROM, and >I think that must include the data from the catalog, since it runs without >needing anything else. That program is mainly for statistical searches, >e.g., "list all the stars in the HIP/TYC catalog within <n> parsecs of the >Sun (i.e. with parallax greater than 1/n arcseconds) whose annual motion is >between <lower limit> and <upper limit>," but that's not really what you >need. So you'll need to download the catalog and write a program to read >it and do the calculations you need. > I once trying to find Nexon-Solaria, based on the fact that they should be G-type stars that lie about 2 parsecs apart. I ended up with too many pairs :-( Alberto Monteiro _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
