J/ApJ/788/L9 Stellar parameters of KIC planet-host stars (Bastien+, 2014)
Larger planet radii inferred from stellar "flicker" brightness variations
of bright planet-host stars.
Bastien F.A., Stassun K.G., Pepper J.
<Astrophys. J., 788, L9 (2014)>
=2014ApJ...788L...9B 2014ApJ...788L...9B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Effective temperatures ;
Photometry
Keywords: planets and satellites: fundamental parameters -
stars: fundamental parameters - techniques: photometric
Abstract:
Most extrasolar planets have been detected by their influence on their
parent star, typically either gravitationally (the Doppler method) or
by the small dip in brightness as the planet blocks a portion of the
star (the transit method). Therefore, the accuracy with which we know
the masses and radii of extrasolar planets depends directly on how
well we know those of the stars, the latter usually determined from
the measured stellar surface gravity, log g. Recent work has
demonstrated that the short-timescale brightness variations
("flicker") of stars can be used to measure log g to a high accuracy
of ∼0.1-0.2 dex. Here, we use flicker measurements of 289 bright
(Kepmag<13) candidate planet-hosting stars with Teff=4500-6650 K
to re-assess the stellar parameters and determine the resulting impact
on derived planet properties. This re-assessment reveals that for the
brightest planet-host stars, Malmquist bias contaminates the stellar
sample with evolved stars: nearly 50% of the bright planet-host stars
are subgiants. As a result, the stellar radii, and hence the radii of
the planets orbiting these stars, are on average 20%-30% larger than
previous measurements had suggested.
Description:
We draw our bright KOI sample from the NASA Exoplanet Archive (NEA;
Akeson et al. 2013PASP..125..989A 2013PASP..125..989A) accessed on 2014 January 7. We
restrict the sample to stars with 6650 K>Teff>4500 K, the Teff
range for which F8 is calibrated. We exclude 28 stars with overall
range of photometric variability >10 ppt (parts per thousand), as
phenomena in the light curves of such chromospherically active stars
can boost the measured F8 and thus result in an erroneous F8-based
log g. These excluded stars (10% of the sample) are cooler than
average for the overall sample, as expected given their large
variability. Our sample after applying these cuts contains 289 stars
(407 KOIs).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 38 289 Stellar parameters for study sample
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/MNRAS/436/1883 : Properties of KOI host stars (Walkowicz+, 2013)
J/ApJ/783/123 : Surface gravity for 220 Kepler stars (Campante+, 2014)
J/ApJ/818/43 : Stellar surface gravity measures of KIC stars
(Bastien+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- KIC Kepler Input Catalog identifier (KIC NNNNNNNN)
11- 15 F5.2 mag Kepmag Kepler magnitude
17- 20 I4 K Teff Effective temperature
22- 25 F4.2 [cm/s2] loggF8 Log surface gravity from 8-hr "flicker"
27- 30 F4.2 [cm/s2] loggNEA Log surface gravity from NASA
Exoplanet Archive
32- 35 F4.2 10-3 RVar Brightness variation range (in ppt unit)
38 I1 --- r_loggNEA [1/3] Reference for loggNEA (1)
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Note (1): Reference as follows:
1 = asteroseismic (72 stars);
2 = spectroscopic (78 stars);
3 = photometric (139 stars).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 03-Jul-2017