Neptune-mass planet at Lam2 Fornacis.

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Neptune-mass planet at Lam2 Fornacis.

Post by Sirius_Alpha on 24th February 2009, 10:13 pm

A Neptune-mass Planet Orbiting the Nearby G Dwarf HD16417
http://arxiv.org/abs/0902.4024

Abstract wrote:Precision Doppler measurements from an intensive 48 night "Rocky Planet Search" observing campaign on the Anglo-Australian Telescope (AAT) have revealed the presence of a low-mass exoplanet orbiting the G1 dwarf HD16417. Subsequent Doppler observations with the AAT, as well as independent observations obtained by the Keck Planet Search, have confirmed this initial detection and refine the orbital parameters to period 17.24+/-0.01 d, eccentricity 0.20+/-0.09, orbital semi-major axis 0.14+/-0.01 AU and minimum planet mass 22.1+/-2.0 Mearth. HD 16417 raises the number of published exoplanets with minimum masses of less than 25 Mearth to eighteen. Interestingly, the distribution of detected sub-25 Mearth planets over the spectral types G, K and M is almost uniform. The detection of HD 16417b by an intensive observing campaign clearly demonstrates the need for extended and contiguous observing campaigns when aiming to detect low-amplitude Doppler planets in short period orbits. Perhaps most critically it demonstrates that the search for low-mass Doppler planets will eventually require these traditional "bright-time" projects to extend throughout dark lunations.

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Re: Neptune-mass planet at Lam2 Fornacis.

Post by Edasich on 25th February 2009, 7:04 am

A hot Neptune from AAT target list.
Now I'm waiting for Epsilon Fornacis. Very Happy
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Re: Neptune-mass planet at Lam2 Fornacis.

Post by Lazarus on 25th February 2009, 6:13 pm

From my quick scan of the paper, no mention of transits at all. (I.e. no indication that they've been searched for yet)

Interesting.
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Re: Neptune-mass planet at Lam2 Fornacis.

Post by Edasich on 26th February 2009, 6:15 pm

Performing a Systemic simulation, there's a strong evidence of additional companion (<0.13 Mj) in 339 days or less orbit.
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Re: Neptune-mass planet at Lam2 Fornacis.

Post by Lazarus on 26th February 2009, 6:59 pm

As is said in the paper there is a 289-day periodicity, however the significance is low. Also the eccentricity is suspiciously high: my best fit 2-Keplerian fit has crossing orbits. Using the stability checker on my best 2-planet solution with the second planet's period near 289 days, the inner planet's eccentricity eventually reaches a value where the planet would hit the star at periastron.
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Re: Neptune-mass planet at Lam2 Fornacis.

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