Sent to you by Sean McBride via Google Reader: HUGE EXOPLANET NEWS
ITEMS: PICTURES!!! via RSSmeme by Phil Plait on 11/13/08
Shared 121 times Tagged astronomy (637) Cool Stuff (786) Pretty
pictures (167) Science (4088)

This is incredible: For the first time, ever, astronomers have captured
an optical image of a planet orbiting a star like our own.

And that’s not all: we also have a second picture showing TWO planets
orbiting a second star!

(Calm down. Breathe, breathe.)

The first picture is from Hubble. Ready? Here it is:

Do you see it? That tiny spark, that wee blip of light? It may not look
like much, but it is in fact a normal planet orbiting a normal star,
250 trillion kilometers from Earth.

Holy Haleakala.

The picture as a whole needs some splainin’. The star in question is
Fomalhaut, a star easily visible to the unaided eye; it’s the brightest
star in Aquarius, the 18th brightest in the sky, and only 25 light
years away. It’s literally millions of times brighter than the planet,
so the Hubble camera uses an occulting bar, a small piece of metal that
blocks the brightest part of the star’s image. The blacked-out area in
the center of the picture is where Fomalhaut is (also, the star’s image
has been digitally subtracted using an image of another star as a
template; that further reduces the amount of unwanted light). The
radial lines are not real; they are an optical effect of the very
bright star. The ring is real; it’s dust leftover from the formation of
the star and the planet. In fact, the thinness of the ring was a big
factor in assuming a planet was lurking there; the planet’s gravity
sculpts the ring, keeping it narrowly confined. Also, the ring is
off-center from the star, and a planet in an elliptical orbit would
explain that nicely.

The planet itself is just that small dot, almost lost in the noise from
the star and the light from the ring. I’ll be honest; had I been
analyzing the image, I might have missed it at first. But it’s there,
and it’s real. Images taken almost two years apart show that the planet
is moving with the star, and is consistent with it orbiting Fomalhaut
at a distance of about 18 billion km (11 billion miles). That’s four
times the distance of Neptune from the Sun. It takes 872 years to make
one complete orbit. The mass is not easy to determine, and is estimated
using its effect on the ring; it’s likely to be about the same size and
mass as Jupiter.

The planet is unnamed, and is simply called Fomalhaut b.

I am reeling from this image. Years ago, when I still worked on Hubble,
I did some work on planetary debris rings like this, including seeing
if we could directly see planets near stars. The amount of work that
goes into this type of discovery is phenomenal, and so I’m stunned by
the success of it.

This is huge news.

And it gets even huger. Because there’s more:

That image is the first to directly show two planets orbiting another
star! It’s a near-infrared image using the giant Gemini North 8 meter
telescope. Like in the Hubble image, the star’s light has been blocked,
allowing the two planets to be seen (labeled b and c).

The star is called HR 8799. It’s a bit more massive (1.5 times) and
more luminous (5x) than the Sun, and lies about 130 light years from
Earth. The planets in this picture orbit it at distances of 6 billion
km (3.6 billion miles) and 10.5 billion km (6.3 billion miles). A third
planet, not seen in this image but discovered later using the Keck 10
meter telescope, orbits the star closer in at a distance of 3.8 billion
km (2.3 billion miles).

So there it is. The first ever family portrait of a planetary system.

One thing that makes these particular planets a bit easier to find than
usual is that they are young; HR 8799 and its children are only about
60 million years old. That means the planets are still glowing from the
leftover heat of their formation, and that adds to their brightness.
Eventually (in millions of years), as they cool, they will glow only by
reflected light from the star, and be far harder to see. Fomalhaut b,
in the Hubble image, is much older (200 million years), and glows only
by reflected light from Fomalhaut. If it were much smaller or dimmer
(or closer to the blinding light of the star), we wouldn’t have been
able to see it at all.

These images were basically science fiction just a few years ago. Now
they are fact. We have an optical picture of a planet orbiting another
sun-like star, and a picture of two planets orbiting another star.

Wow. Just wow.

OK, now that you have the news, a few caveats. We now know of more than
300 planets orbiting other stars. And a planet has been imaged before,
but it was orbiting a brown dwarf, which is different than a normal
star like the Sun. Brown dwarfs are so-called "failed stars", much
smaller than the Sun. Another possible planet orbiting a sun-like star
has been imaged, but has not yet been confirmed. So these images here
really are firsts. They are history.

I still can hardly believe it, and I worked on data like this! Yet
there they are, proof that our planetary system is not the only one in
the Universe. We knew this already; indirect evidence confirms planets
and even multiple planetary systems around many nearby stars.

But there’s nothing like a picture. There, with your own eyes, you can
see for yourself that other planets exist. They are not Earthlike, not
even a little… they are massive, young, hot planets that are probably
mostly gaseous and completely inhospitable.

But there they are.

In a few years, we’ll have more pictures like these. And we’ll get
better. Our telescopes will get bigger, our equipment more sensitive,
our techniques improved as we understand their capabilities. And the
pictures of other planets will roll in.

How long before we see the Holy Grail, the first image of a terrestrial
planet, orbiting a star like the Sun at just the right distance for
liquid water to bathe its surface? It may not be for a decade or two,
but mark my words: that day will arrive. And when it does, well, we’ll
just have to rewrite the history books again, won’t we?

- Hadyn said: really very cool
- Ember Case said: Am I the only one that sees the Starship Enterprise
in that big black area on the top picture?
- Jon Wiley said: This a different discovery - the first ever *optical*
image of an exoplanet. Fomalhaut b!
- normad said: The world's first images of other planetary
systems--planets orbiting a star, similar to the Earth and our sun.
Very cool!
- ZZamboni said: Very cool!
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