HARPS search in the metal-poor sample

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HARPS search in the metal-poor sample

Post by Borislav on 10th November 2010, 2:55 am

http://arxiv.org/pdf/1011.2094


5.3.4. Ambiguous cases: new candidate planets

HD107094: A total of 14 radial velocities were obtained for this star, showing a clear long-term (quasi-linear) radialvelocity signal. Twelve of these measurements were obtained within the HARPS GTO program, and a last two in July 2010 under ESO program 085.C-0063. In a first analysis, the total amplitude (∼2.5 kms−1 over 2355days) suggests there is a stellar or sub-stellar companion orbiting this 0.8 solar mass star. A single Keplerian fit to the data shows that it is well fit by a long-period Keplerian function, though the orbital parameters are difficult to constrain (see Fig. 11). The residuals of this fit, on the order of 2.1ms−1, are still high, and they called attention to a different possible orbital solution to the system. Indeed, a fit of the linear drift together with a Keplerian function reveals the presence of a possible shorter period solution, with P∼1870days, K=88ms−1, and e=0.13 (Table 5.3.4). This signal, first detected using only the GTO data, is compatible with the presence of a 4.5 Jupiter mass companion. The residuals of this fit (1.10ms−1) are significantly better than in the previous case. The fitted linear trend (which, to our knowledge,
has not been previously reported in the literature) has a slope of 4021m/s/yr. More data are now
needed to disentangle the two possible solutions, but we are likely seeing a new giant planet. Interestingly, with [Fe/H]=−0.51 (Sousa et al. 2010), HD107094 is close to the high-metallicity limit of our sample.

HD197083: Although the statistical analysis done for this star does not indicate any strong signal, a visual inspection of the radial velocities hints at the presence of a long-term periodic signal (P∼1500-2000days), see Fig. 8. The number of points covering the first ∼1000 days is
very reduced (3) with high error bars. More data are thus clearly needed to confirm this signal.

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Re: HARPS search in the metal-poor sample

Post by Edasich on 10th November 2010, 6:33 am

A yet unconfirmed planet. What a pity Laughing
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Re: HARPS search in the metal-poor sample

Post by Lazarus on 10th November 2010, 3:16 pm

Looks like they haven't got sufficient data to determine an unambiguous orbital solution. Probably there is something there though.
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Re: HARPS search in the metal-poor sample

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