J/AJ/154/228 Properties of transiting planet's host stars (Sandford+, 2017)
Know the planet, know the star: precise stellar densities from Kepler transit
light curves.
Sandford E., Kipping D.
<Astron. J., 154, 228 (2017)>
=2017AJ....154..228S 2017AJ....154..228S (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Stars, diameters ; Models
Keywords: eclipses - planetary systems - planets and satellites: general -
methods: data analysis
Abstract:
The properties of a transiting planet's host star are written in its
transit light curve. The light curve can reveal the stellar density
(ρ*) and the limb-darkening profile in addition to the
characteristics of the planet and its orbit. For planets with strong
prior constraints on orbital eccentricity, we may measure these stellar
properties directly from the light curve; this method promises to aid
greatly in the characterization of transiting planet host stars targeted
by the upcoming NASA Transiting Exoplanet Survey Satellite mission and
any long-period, singly transiting planets discovered in the same systems.
Using Bayesian inference, we fit a transit model, including a nonlinear
limb-darkening law, to 66 Kepler transiting planet hosts to measure their
stellar properties. We present posterior distributions of ρ*,
limb-darkening coefficients, and other system parameters for these stars.
We measure densities to within 5% for the majority of our target stars,
with the dominant precision-limiting factor being the signal-to-noise
ratio of the transits. Of our measured stellar densities, 95% are in
3σ or better agreement with previously published literature
values. We make posterior distributions for all of our target Kepler
objects of interest available online at 10.5281/zenodo.1028515.
Description:
In this work, we fit transit models to a large sample of Kepler host stars
to build an empirical catalog of transit-derived stellar densities and
limb-darkening coefficients and demonstrate that this method is capable of
delivering precise constraints on these stellar parameters. We draw KOIs
with observed secondary eclipses (hereafter "occultation targets") from
catalogs compiled by Coughlin & Lopez-Morales (2012, J/AJ/143/39) and
Shabram et al. (2016ApJ...820...93S 2016ApJ...820...93S). The resulting occultation target
list, comprising 44 KOIs (the majority of our targets), is presented
in Table 1. Our second target population consists of KOIs with short tidal
circularization timescales τcirc ("tidal targets"). The remaining 13
tidal targets are listed in Table 2. Finally, we consider compact
multi-planet systems, which are not expected to be dynamically stable
unless their constituent planets are on low-eccentricity orbits. The
remaining nine systems, comprising 18 KOIs, are listed in Table 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 257 44 Occultation targets
table2.dat 257 13 Tidally circularized ("tidal") targets
table3.dat 257 18 Compact multi-planet systems ("multis")
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/A+A/510/A21 : Stellar Limb-Darkening Coefficients (Sing, 2010)
J/AJ/143/39 : Analysis of hot Jupiters in Kepler Q2 (Coughlin+, 2012)
Byte-by-byte Description of file: table1.dat table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 --- KOI [1.01/7449.01] Kepler Object of Interest
number
9- 16 I8 --- KIC [3115833/12644822] Kepler Input Catalog
identifier
18- 26 F9.5 d t0 [121.1195/374.79] Transit epoch (BKJD)
28- 34 E7.1 d E_t0 Upper uncertainty on t0
36- 43 A8 d e_t0 Lower uncertainty on t0
45- 57 F13.8 d Porb [0.5828955/104.8213] Orbital period
59- 66 E8.2 d E_Porb [1e-08/0.016] Upper uncertainty on Porb
68- 75 E8.2 d e_Porb [1e-08/0.0201] Lower uncertainty on Porb
77- 82 F6.4 --- b [0.02/1.91] Impact parameter
84- 89 F6.4 --- E_b [0.0004/0.84] Upper uncertainty on b
91- 96 F6.4 --- e_b [0.0003/0.9] Lower uncertainty on b
98-103 F6.4 [kg/m3] log10rho* [0.7/5.0355] Stellar density, log10
(log10(ρ*))
105-110 F6.4 [kg/m3] E_log10rho* [0.0007/2.2] Upper uncertainty on log10rho*
112-117 F6.4 [kg/m3] e_log10rho* [0.0036/2] Lower uncertainty on log10rho*
119-125 F7.5 --- Rp/R* [0.003/0.98] Ratio of radii
127-133 F7.5 --- E_Rp/R* [7e-05/0.68] Upper uncertainty on Rp/R*
135-141 F7.5 --- e_Rp/R* [0.0001/0.5] Lower uncertainty on Rp/R*
143-149 F7.4 --- secw [-0.8/0.8987] sqrt(e)cosω
(e=eccentricity, ω=argument of
periastron)
151-156 F6.4 --- E_secw [0.0004/0.8] Upper uncertainty on secw
158-163 F6.4 --- e_secw [0.0007/0.6] Lower uncertainty on secw
165-172 F8.5 --- sesw [-0.6/0.767] sqrt(e)sinω
(e=eccentricity, ω=argument of
periastron)
174-180 F7.5 --- E_sesw [9e-05/0.8] Upper uncertainty on sesw
182-188 F7.5 --- e_sesw [0.0006/0.4] Lower uncertainty on sesw
190-196 F7.5 --- a(r) [8e-05/0.999] Coefficient r of modified
nonlinear limb darkening law αr
198-204 F7.5 --- E_a(r) [0.001/0.6] Upper uncertainty on a(r)
206-212 F7.5 --- e_a(r) [8e-05/0.5] Lower uncertainty on a(r)
214-220 F7.5 --- a(h) [4e-05/0.999] Coefficient h of modified
nonlinear limb darkening law αh
222-228 F7.5 --- E_a(h) [0.0002/0.7] Upper uncertainty on a(h)
230-236 F7.5 --- e_a(h) [4e-05/0.5] Lower uncertainty on a(h)
238-243 F6.4 --- a(t) [0.07/0.991] Coefficient θ of
modified nonlinear limb darkening law
αθ
245-250 F6.4 --- E_a(t) [0.0002/0.86] Upper uncertainty on a(t)
252-257 F6.4 --- e_a(t) [0.0013/0.5] Lower uncertainty on a(t)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 16-Aug-2018