GJ 876 d IR detection (with failure to detect an atmosphere)

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GJ 876 d IR detection (with failure to detect an atmosphere)

Post by Sirius_Alpha on 17th September 2009, 3:20 am

On the Method to Infer an Atmosphere on a Tidally Locked Super Earth Exoplanet and Upper Limits to GJ 876d
http://www.iop.org/EJ/abstract/0004-637X/703/2/1884

Abstract wrote:We develop a method to infer or rule out the presence of an atmosphere on a tidally locked hot super Earth. The question of atmosphere retention is a fundamental one, especially for planets orbiting M stars due to the star's long-duration active phase and corresponding potential for stellar-induced planetary atmospheric escape and erosion. Tidally locked planets with no atmosphere are expected to show a Lambertian-like thermal phase curve, causing the combined light of the planet-star system to vary with planet orbital phase. We report Spitzer 8 μm IRAC observations of GJ 876 taken over 32 continuous hours and reaching a relative photometric precision of 3.9 104 per point for 25.6 s time sampling. This translates to a 3σ limit of 5.13 105 on a planet thermal phase curve amplitude. Despite the almost photon-noise-limited data, we are unable to conclusively infer the presence of an atmosphere or rule one out on the non-transiting short-period super Earth GJ 876d. The limiting factor in our observations was the miniscule, monotonic photometric variation of the slightly active host M star, because the partial sine wave due to the planet has a component in common with the stellar linear trend. The proposed method is nevertheless very promising for transiting hot super Earths with the James Webb Space Telescope and is critical for establishing observational constraints for atmospheric escape.

Or at least I interpret this as the planet having been detected, even if only barely, due to the "the partial sine wave due to the planet has a component in common with the stellar linear trend." part (as well as how this paper is cited in other papers). If I'm wrong, let me know.

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Re: GJ 876 d IR detection (with failure to detect an atmosphere)

Post by Stalker on 17th September 2009, 12:52 pm

It is a Project or Spitzer have already detected Gj876 d in IR?

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Re: GJ 876 d IR detection (with failure to detect an atmosphere)

Post by Sirius_Alpha on 17th September 2009, 4:07 pm

The measurements have already been taken.

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Re: GJ 876 d IR detection (with failure to detect an atmosphere)

Post by Lazarus on 18th September 2009, 5:09 pm

Pity the paper is locked behind a paywall, looks like a very interesting one... wonder if this is going to hit the arXiv eventually.

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Re: GJ 876 d IR detection (with failure to detect an atmosphere)

Post by Sirius_Alpha on 8th October 2009, 11:40 pm

Lazarus wrote:... wonder if this is going to hit the arXiv eventually.

The ArXiv hears your wish.
http://arxiv.org/abs/0910.1505

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Re: GJ 876 d IR detection (with failure to detect an atmosphere)

Post by Edasich on 9th October 2009, 7:40 am

Alike the genie of the lamp Laughing

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Re: GJ 876 d IR detection (with failure to detect an atmosphere)

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