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TOPIC: Transiting Planet Candidates

Blobrana

L

Posts: 131433

Date: Jun 9 14:38 2012

RE: Transiting Planet Candidates	Permalink

Title: An Efficient Automated Validation Procedure for Exoplanet Transit Candidates Authors: Timothy D. Morton Surveys searching for transiting exoplanets have found many more candidates than they have been able to confirm as true planets. This situation is especially acute with the Kepler survey, which has found over 2300 candidates but has confirmed only 61 planets to date. I present here a general procedure that can quickly be applied to any planet candidate to calculate its false positive probability. This procedure takes into account the period, depth, duration, and shape of the signal; the colours of the target star; arbitrary spectroscopic or imaging follow-up observations; and informed assumptions about the populations and distributions of field stars and multiple-star properties. I also introduce the concept of the "specific occurrence rate," which allows for the calculation of the FPP without relying on an assumed planet radius function. Applying these methods to a sample of known Kepler planets, I demonstrate that many signals can be validated with very limited follow-up observations: in most cases with only a spectrum and an AO image. Additionally, I demonstrate that this procedure can reliably identify false positive signals. Because of the computational efficiency of this analysis, it is feasible to apply it to all Kepler planet candidates in the near future, and it will streamline the follow-up efforts for Kepler and other current and future transit surveys. Read more (855kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jun 5 14:51 2012

Kepler transit candidates	Permalink

Title: SOPHIE velocimetry of Kepler transit candidates VI. A false positive rate of 35% for Kepler close-in giant candidates Authors: A. Santerne, R. F. Díaz, C. Moutou, F. Bouchy, G. Hébrard, J.-M. Almenara, A. S. Bonomo, M. Deleuil, N. C. Santos The false positive probability (FPP) of Kepler transiting candidates is a key value for statistical studies of candidate properties. An investigation of the stellar population in the Kepler field by Morton & Johnson (2011) has provided an estimation for the FPP of less than 5% for most of the candidates. We report here the results of our radial velocity observations on a sample of 46 Kepler candidates with transit depth greater than 0.4%, orbital period less than 25 days and host star brighter than Kepler magnitude 14.7. We used the SOPHIE spectrograph mounted on the 1.93-m telescope at the Observatoire de Haute-Provence to establish the nature of the transiting candidates. In this sample, we found 5 undiluted eclipsing binaries, 2 brown dwarfs, 6 diluted eclipsing binaries and 9 new transiting planets that complete the 11 already published. The remaining 13 candidates were not followed up or remain unsolved due to photon noise limitation or lack of observations. From these results we compute the FPP for Kepler close-in giant candidates to be 34.8% \pm 6.5%. We investigate the variation of FPP for giant candidates with the longer orbital periods and find that it should be up to 40% for orbital periods in-between 10 days and 200 days. We thus find a significant discrepancy with the estimation of Morton & Johnson (2011). We finally discuss the reasons of this discrepancy and the possible extension of this work towards smaller planet candidates. Read more (4396kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jun 1 04:07 2012

Transiting Planet Candidates	Permalink

Title: 16 New Transiting Planet Candidates from Kepler Q1-Q6 Data Authors: Xu Huang (1), Gáspár A. Bakos (1,2), Joel D. Hartman (1) ((1) Department of Astrophysical Sciences, Princeton University, (2) Alfred P. Sloan Research Fellow) We have performed an extensive search for planet candidates in the publicly available Kepler Long Cadence data from quarters Q1 through Q6. The search method consists of initial de-trending of the data, applying the trend filtering algorithm, searching for transit signals with the Box Least Squares fitting method in two frequency domains, visual inspection of the potential transit candidates, and in-depth analysis of the shortlisted candidates. In this paper we present 16 new periodic planet candidates and 8 single transit events. The periods of these planet candidates vary from ~0.968 day to ~440 day. Nine of the planet candidates have radii smaller than 3 earth radii. We also report seven newly identified false positives---systems that look like transiting planets, but are probably due to blended eclipsing binaries. Read more (936kb, PDF) __________________

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