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Fraser
2005-May-02, 05:02 PM
SUMMARY: Astronomers working with the European Southern Observatory have confirmed the first direct photograph of a planet orbiting another star. The team originally announced their discovery in September 2004, but they confirmed their findings this year using the powerful new NACO instrument on ESO's Very Large Telescope in northern Chile. The planet is approximately five times the size of Jupiter, and orbits its brown dwarf star at about the distance that Neptune travels around the Sun.

View full article (http://www.universetoday.com/am/publish/exoplanet_image_confirmed.html)

What do you think about this story? Post your comments below.

om@umr.edu
2005-May-02, 06:57 PM
Thanks, Fraser, for this new report.

They have not observed planets like Earth, capable of supporting life, orbiting other stars.

"Given the rather unusual properties of the 2M1207 system, the giant planet most probably did not form like the planets in our solar system," says Gael Chauvin. "Instead it must have formed the same way our Sun formed, by a one-step gravitational collapse of a cloud of gas and dust."

Are the planets orbiting the pulsar, PSR1257+12, the only Earth-like planets known outside our solar system?

With kind regards,

Oliver
http://www.umr.edu/~om

Joe
2005-May-02, 06:58 PM
Stunning.
'They' told me this wouldn't happen in my lifetime - imagining a planet circling a star (other than the sun). Next, we'll be walking around on Mars. Count on it.

It's still a great time to be into astronomy.

Don Alexander
2005-May-02, 07:13 PM
Well, there are still problems with defining what a planet actually is.

According to the "definition" of the International Astronomical Union, it is one:

http://www.ciw.edu/IAU/div3/wgesp/definition.html

A tighter definition is along the lines "a metal-rich, spherical non-fusor created contemporaneously around a fusor and orbiting this fusor" - sounds complicated, but it means that it is an object that does not support any kind of fusion (being lighter than the brown dwarf mass limit of 13 Jupiter masses) in orbit around a real star.

Since 2M1207 is a brown dwarf and not a real star, and the authors actually state that this object did not form like a classical planet (out of the accretion disk around the newborn star), it is more like a "sub-brown dwarf".

wstevenbrown
2005-May-02, 08:33 PM
Here are the citations for the planet imaging:

http://arxiv.org/astro-ph/0504659

http://arxiv.org/astro-ph/0504658

The second is about a body near the mass cutoff between planet and brown dwarf.

Why are we so bound up in the familiar? There is a basis for comparison, but it shouldn't be a Procrustean bed. It moves like a planet, it glows like a (newborn) planet... it's a planet. Where it formed should be irrelevant. We are going to find a lot of rogue or captured bodies in future. These should be subclassifications at best, not disqualifications.

Enjoy! Steve

Greg
2005-May-03, 02:21 AM
There weasn't much doubt in my mind nor many other people's minds from the start given the proximity of these objects to each other that they were part of the same solar system. Theis data just clinches it beyond reasonable doubt (95% confidence interval.) Still this is an exceptional find and not the norm. These aren't many relatively nearby nascent systems with brown dwarfs and such a system is ideal for spotting planets due to the lack of luminosity of the dwarf and the still hot state of the newly formed planet. Nevertheless, such finds are a useful warmup for what is to come in the near future with better and better optical devices. Investigators will be able to use techniques honed on these objects and apply them to more numerous finds that will come when the big planet finders hit the skies and outer space.

wstevenbrown
2005-May-03, 03:59 AM
On second reading, same quibble as last year. The separation given is tangential only. The line-of-sight separation is unknown, and could be as large as 7-10LY. No orbital period or elements are observed, and the pair may only be as 'coupled' as Sol and Sirius. The orbital period could be 150Y or 1,500,000Y. [snivel] [whine] S

Nereid
2005-May-03, 01:40 PM
It seems you are an impatient man Steve!

Definitions do matter ... think 'electron' and 'anti-proton' or 'negative ion', without clear definitions the folk actually doing physics would have a very difficult time communicating with one another (let alone the rest of us)!

And since the engine of science is theory formation (etc), the ability to distinguish between a condensed body which formed in the same manner as the Sun (crudely, gravitational collapse of a cloud) and one which formed like Jupiter did (crudely, by accretion) matters a great deal to those developing theories and those testing those theories through observation.

Guest
2005-May-04, 12:53 PM
Originally posted by Nereid@May 3 2005, 01:40 PM
And since the engine of science is theory formation (etc), the ability to distinguish between a condensed body which formed in the same manner as the Sun (crudely, gravitational collapse of a cloud) and one which formed like Jupiter did (crudely, by accretion) matters a great deal to those developing theories and those testing those theories through observation.
I agree, Nereid.

However measurements convince some of us that the Sun formed by accretion too.

With kind regards,

Oliver
http://www.umr.edu/~om

Planetwatcher
2005-May-04, 07:46 PM
As much as I'd like to see exo-planets directly imaged, I have a real problem with swallowing this particular pill, and I think the rest of you folks might be missing something.

Look at that photo again. Notice that the planet is much brighter then it's parent star? Which by the way is a brown dwarf.
Planets don't produce light, so where is this one refecting it's light from?
Reflections are never brigher then the origional source they are reflecting. At best they are as bright.

Now had the star been at least a red main sequence, I might have believed it, but with a brown dwarf, I will remain skeptical.