A year after announcing Glize 581e...

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A year after announcing Glize 581e...

Post by Borislav on 23rd April 2010, 4:13 pm

Year has passed since the last great discoveries of exoplanets. Why Geneva Group no longer pleases his great discoveries?
In the past year, every spring they amazed everyone with his great discoveries:

2006 (May 17) - a system of three Neptune
2007 (April 25) - two super Earth system Gliese 581 (including near the habitable zone)
2008 (26 June) - a system of three super Earth
2009 (April 21) - the fourth planet in 2 Earth masses at Gliese 581

In general, I am beginning to get bored ...

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Re: A year after announcing Glize 581e...

Post by Lazarus on 23rd April 2010, 4:27 pm

Borislav wrote:In general, I am beginning to get bored ...
I don't think the purpose of the Geneva Group is to keep Borislav amused though...

Seriously, the observation process is difficult, especially if you are going for low-mass planets. Low semi-amplitudes, stellar noise and the apparently high frequency of multi-planet systems mean you need very large datasets and even then there is possibility of confusion. (E.g. the aliased period of Gl 581d)
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Re: A year after announcing Glize 581e...

Post by Borislav on 23rd April 2010, 4:52 pm



But somehow the last four years, the major announcements of the Geneva group to come to the late spring - early summer. Ie some meaning apparently is, as Michael Brown, who his main discoveries in the Kuiper Belt had in store for many months after the discovery.
I personally think that this year's Geneva Group will delight announcement of the five-planetary system, which was first mentioned at a conference in Brazil in August 2009.

http://www.infox.ru/science/universe/2009/10/19/ESOssignificantexoplanetfind.phtml
As recognized by scientists at a press conference in their sleeve there are several dozen candidates for exoplanets, which they still do not have to report, so as not very well measure their parameters. Period of some of the planets is more than five years, so for reliable determination of their mass and distance from the star so far is just not enough observational data. According to Santos, in the coming months, waiting for us and the announcement of the discovery of several small masses of the planets.

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Re: A year after announcing Glize 581e...

Post by Sirius_Alpha on 23rd April 2010, 6:07 pm

Consider the long period of silence a good thing. Multiple planets take longer to characterise. The Geneva team said specifically that they have had cases where after they characterize a planet, a second signal becomes apparent. Then they have to observe long enough to constrain this second signal, in which time a third begins to show up. Remember, HARPS does have a 5-planet system, and with as many planets as are rumored to have been found, one would expect that it would take a while.

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Re: A year after announcing Glize 581e...

Post by Borislav on 22nd August 2010, 8:53 am

Now I understood the answer to the reasons for the delay. The Geneva group waited August, to mark the 15 th anniversary of the discovery 51 Pegasi!

The main gain a lot of patience. Smile

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Re: A year after announcing Glize 581e...

Post by Sirius_Alpha on 22nd August 2010, 10:45 am

I thought 51 Peg b was announced in October 1995?

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Re: A year after announcing Glize 581e...

Post by Borislav on 22nd August 2010, 11:07 am

Sirius_Alpha wrote:I thought 51 Peg b was announced in October 1995?

Good question. The fact that it was in late August 1995, the Geneva group knew about the existence of a hot Jupiter. This is clearly seen from the date of receipt of the spectra 51 Pegasi. At first, looking for long-periodical planet, and then decided to test the short-periodic signals (when no one knew about the hot Jupiter).

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Re: A year after announcing Glize 581e...

Post by Sirius_Alpha on 22nd August 2010, 11:16 am

Wow, that's pretty neat. Definitely a clear change in observation strategy. Perhaps folding the first set of RV data, they kept finding that ~3 day periodicity so the apparent change in strategy could be to try to observe such a periodicity as it happens.

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