Low false positive rate of kepler candidates estimated from a combination of spitzer and follow-up observations

Jean Michel Désert, David Charbonneau, Guillermo Torres, Francois Fressin, Sarah Ballard, Stephen T. Bryson, Heather A. Knutson, Natalie M. Batalha, William J. Borucki, Timothy M. Brown, Drake Deming, Eric B. Ford, Jonathan J. Fortney, Ronald L. Gilliland, David W. Latham, Sara Seager

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

NASA's Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate's transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85%), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5% and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8% at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated by the Kepler observations, provides an independent indication that Kepler's FPR is low.

Original languageEnglish (US)
Article number59
JournalAstrophysical Journal
Volume804
Issue number1
DOIs
StatePublished - May 1 2015

Fingerprint

transit
planets
planet
Kepler mission
estimating
limb darkening
stars
Space Infrared Telescope Facility
star distribution
eclipses
set theory
photometry
limb
rate
confidence
indication
occurrences
orbitals

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Désert, J. M., Charbonneau, D., Torres, G., Fressin, F., Ballard, S., Bryson, S. T., ... Seager, S. (2015). Low false positive rate of kepler candidates estimated from a combination of spitzer and follow-up observations. Astrophysical Journal, 804(1), [59]. https://doi.org/10.1088/0004-637X/804/1/59
Désert, Jean Michel ; Charbonneau, David ; Torres, Guillermo ; Fressin, Francois ; Ballard, Sarah ; Bryson, Stephen T. ; Knutson, Heather A. ; Batalha, Natalie M. ; Borucki, William J. ; Brown, Timothy M. ; Deming, Drake ; Ford, Eric B. ; Fortney, Jonathan J. ; Gilliland, Ronald L. ; Latham, David W. ; Seager, Sara. / Low false positive rate of kepler candidates estimated from a combination of spitzer and follow-up observations. In: Astrophysical Journal. 2015 ; Vol. 804, No. 1.
@article{e2524d66de174bd1b21788c4ed7200de,
title = "Low false positive rate of kepler candidates estimated from a combination of spitzer and follow-up observations",
abstract = "NASA's Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate's transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85{\%}), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5{\%} and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8{\%} at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated by the Kepler observations, provides an independent indication that Kepler's FPR is low.",
author = "D{\'e}sert, {Jean Michel} and David Charbonneau and Guillermo Torres and Francois Fressin and Sarah Ballard and Bryson, {Stephen T.} and Knutson, {Heather A.} and Batalha, {Natalie M.} and Borucki, {William J.} and Brown, {Timothy M.} and Drake Deming and Ford, {Eric B.} and Fortney, {Jonathan J.} and Gilliland, {Ronald L.} and Latham, {David W.} and Sara Seager",
year = "2015",
month = "5",
day = "1",
doi = "10.1088/0004-637X/804/1/59",
language = "English (US)",
volume = "804",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

Désert, JM, Charbonneau, D, Torres, G, Fressin, F, Ballard, S, Bryson, ST, Knutson, HA, Batalha, NM, Borucki, WJ, Brown, TM, Deming, D, Ford, EB, Fortney, JJ, Gilliland, RL, Latham, DW & Seager, S 2015, 'Low false positive rate of kepler candidates estimated from a combination of spitzer and follow-up observations', Astrophysical Journal, vol. 804, no. 1, 59. https://doi.org/10.1088/0004-637X/804/1/59

Low false positive rate of kepler candidates estimated from a combination of spitzer and follow-up observations. / Désert, Jean Michel; Charbonneau, David; Torres, Guillermo; Fressin, Francois; Ballard, Sarah; Bryson, Stephen T.; Knutson, Heather A.; Batalha, Natalie M.; Borucki, William J.; Brown, Timothy M.; Deming, Drake; Ford, Eric B.; Fortney, Jonathan J.; Gilliland, Ronald L.; Latham, David W.; Seager, Sara.

In: Astrophysical Journal, Vol. 804, No. 1, 59, 01.05.2015.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Low false positive rate of kepler candidates estimated from a combination of spitzer and follow-up observations

AU - Désert, Jean Michel

AU - Charbonneau, David

AU - Torres, Guillermo

AU - Fressin, Francois

AU - Ballard, Sarah

AU - Bryson, Stephen T.

AU - Knutson, Heather A.

AU - Batalha, Natalie M.

AU - Borucki, William J.

AU - Brown, Timothy M.

AU - Deming, Drake

AU - Ford, Eric B.

AU - Fortney, Jonathan J.

AU - Gilliland, Ronald L.

AU - Latham, David W.

AU - Seager, Sara

PY - 2015/5/1

Y1 - 2015/5/1

N2 - NASA's Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate's transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85%), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5% and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8% at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated by the Kepler observations, provides an independent indication that Kepler's FPR is low.

AB - NASA's Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate's transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85%), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5% and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8% at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated by the Kepler observations, provides an independent indication that Kepler's FPR is low.

UR - http://www.scopus.com/inward/record.url?scp=84928783643&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84928783643&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/804/1/59

DO - 10.1088/0004-637X/804/1/59

M3 - Article

AN - SCOPUS:84928783643

VL - 804

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 59

ER -