J/AJ/156/264 California-Kepler Survey. VII. Planet radius gap (Fulton+, 2018)
The California-Kepler Survey.
VII. Precise planet radii leveraging Gaia DR2 reveal the stellar mass dependence
of the planet radius gap.
Fulton B.J., Petigura E.A.
<Astron. J., 156, 264 (2018)>
=2018AJ....156..264F 2018AJ....156..264F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Effective temperatures ;
Abundances, [Fe/H] ; Photometry, infrared ; Stars, masses ;
Parallaxes, trigonometric ; Stars, diameters ; Stars, ages
Keywords: planetary systems
Abstract:
The distribution of planet sizes encodes details of planet formation
and evolution. We present the most precise planet size distribution to
date based on Gaia parallaxes, Kepler photometry, and spectroscopic
temperatures from the California-Kepler Survey. Previously, we measured
stellar radii to 11% precision using high-resolution spectroscopy; by
adding Gaia astrometry, the errors are now 3%. Planet radius measurements
are, in turn, improved to 5% precision. With a catalog of ∼1000 planets
with precise properties, we probed in fine detail the gap in the planet
size distribution that separates two classes of small planets, rocky
super-Earths and gas-dominated sub-Neptunes. Our previous study and
others suggested that the gap may be observationally under-resolved and
inherently flat-bottomed, with a band of forbidden planet sizes. Analysis
based on our new catalog refutes this; the gap is partially filled in.
Two other important factors that sculpt the distribution are a planet's
orbital distance and its host-star mass, both of which are related to
a planet's X-ray/UV irradiation history. For lower-mass stars, the bimodal
planet distribution shifts to smaller sizes, consistent with smaller stars
producing smaller planet cores. Details of the size distribution including
the extent of the "sub-Neptune desert" and the width and slope of the gap
support the view that photoevaporation of low-density atmospheres is
the dominant evolutionary determinant of the planet size distribution.
Description:
We began with the sample of planet host stars in the California-Kepler
Survey (CKS) sample. The CKS sample selection, spectroscopic observations,
and spectroscopic analysis are described in detail in Petigura et al.
(2017AJ....154..107P 2017AJ....154..107P). In brief, the sample was initially constructed by
selecting all Kepler Objects of Interest (KOIs) brighter than Kp=14.2 mag.
A KOI is a Kepler target star that showed periodic photometric dimmings
indicative of planet transits. However, not all KOIs have received the
necessary follow-up attention needed to confirm the planets. Over the
course of the CKS project, we included additional targets to cover
different planet populations, including multi-candidate hosts,
ultra-short-period candidates, and habitable-zone candidates. We
cross-matched the CKS sample with the Gaia DR2 catalog (Cat. I/345) by
querying all Gaia sources within 1 arcsec of the KIC coordinates. In rare
cases, Gaia detected more than one source within 1 arcsec, and we selected
the source with the smallest difference between G and Kp magnitudes.
We cross-matched 1257 targets in this way.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 178 1189 Stellar properties
table3.dat 154 1901 CKS planet parameters
table4.dat 41 907 Planet detection statistics
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJS/217/31 : Kepler planetary cand. VI. 4yr Q1-Q16 (Mullally+, 2015)
J/MNRAS/452/2127 : Fundamental param. of Kepler stars (Silva Aguirre+, 2015)
J/AJ/154/107 : CKS. I. 1305 stars (Petigura+, 2017)
J/AJ/154/108 : CKS. II. Properties (Johnson+, 2017)
J/AJ/154/109 : CKS. III. Planet radii (Fulton+, 2017)
J/AJ/155/48 : CKS. V. Masses and radii (Weiss+, 2018)
J/AJ/155/89 : CKS. IV. Planets (Petigura+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- KOI Kepler Object of Interest identifier (K0NNNN)
8- 11 I4 K Teff [4618/6656] Effective temperature (1)
13- 14 I2 K E_Teff [60] Upper uncertainty in Teff
16- 17 I2 K e_Teff [60] Lower uncertainty in Teff
19- 23 F5.2 [Sun] [Fe/H] [-0.61/0.47] Metallicity (1)
25- 28 F4.2 [Sun] E_[Fe/H] [0.04] Upper uncertainty in [Fe/H]
30- 33 F4.2 [Sun] e_[Fe/H] [0.04] Lower uncertainty in [Fe/H]
35- 40 F6.3 mag Ksmag [6.491/14.487] 2MASS Ks band magitude
42- 46 F5.3 mag e_Ksmag [0.011/0.119]? Uncertainty in Ksmag
48- 53 F6.3 mas plx [0.302/15.668] Gaia DR2 trigonometric parallax
55- 59 F5.3 mas e_plx [0.011/0.294] Uncertainty in plx
61- 66 F6.3 Rsun R [0.48/10.48] Stellar radius from direct
integration
68- 72 F5.3 Rsun E_R [0.017/0.68] Upper uncertainty in R
74- 78 F5.3 Rsun e_R [0.016/0.615] Lower uncertainty in R
80- 84 F5.3 Msun Miso [0/2.292] Stellar mass from isochrone fit
86- 90 F5.3 Msun E_Miso [0/0.176] Upper uncertainty in Miso
92- 96 F5.3 Msun e_Miso [0/0.258] Lower uncertainty in Miso
98-103 F6.3 Rsun Riso [0/10.072] Stellar radius from isochrone fit
105-109 F5.3 Rsun E_Riso [0/0.713] Upper uncertainty in Riso
111-115 F5.3 Rsun e_Riso [0/0.579] Lower uncertainty in Riso
117-120 F4.2 g/cm3 rhoiso [0/2.57] Stellar density from isochrone fit
122-125 F4.2 g/cm3 E_rhoiso [0/0.24] Upper uncertainty in rhoiso
127-130 F4.2 g/cm3 e_rhoiso [0/0.24] Lpper uncertainty in rhoiso
132-136 F5.2 [yr] logAiso [8.66/10.14]? Log stellar age from isochrone
fit
138-141 F4.2 [yr] E_logAiso [0/0.64]? Upper uncertainty in logAiso
143-146 F4.2 [yr] e_logAiso [0.01/0.8]? Lower uncertainty in logAiso
148-153 F6.3 arcsec plxspec [0.236/16.105] Spectroscopic parallax
155-159 F5.3 arcsec E_plxspec [0.02/1.456] Upper uncertainty in plxspec
161-165 F5.3 arcsec e_plxspec [0.025/3.654] Lower uncertainty in plxspec
167-171 F5.3 --- r8 [1/5.109] Ratio of cumulative flux and target
flux (2)
173-178 F6.4 --- RCF [0/1.4072]? Average radius correction factor
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Note (1): From Petigura et al. (2017, J/AJ/154/107).
Note (2): r8 encodes contaminating flux from neighboring stars within 8 arcsec
in G-band (see Section 4.2).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- KOI Kepler Object of Interest identifier (K0NNNN.NN)
11- 24 F14.9 d Per [0.299697768/1693.6636225] Kepler period (1)
26- 36 F11.9 d E_Per [0/0.1416]? Upper uncertainty in Per
38- 48 F11.9 d e_Per [0/0.1416]? Lower uncertainty in Per
50- 58 F9.6 --- Rp/R* [0.003223/96.986549]? Planet-to-star radius ratio
(1)
60- 68 F9.6 --- E_Rp/R* [0/57.55668]? Upper uncertainty in Rp/R*
70- 78 F9.6 --- e_Rp/R* [7e-06/69.87985]? Lower uncertainty in Rp/R*
80- 88 F9.3 Rgeo Rp [0.276/30653.495]? Planet radius (2)
90- 98 F9.3 Rgeo E_Rp [0.022/12973.748]? Upper uncertainty in Rp
100-108 F9.3 Rgeo e_Rp [0.022/12973.748]? Lower uncertainty in Rp
110-116 F7.5 AU a [0.00797/2.7177]? Semi-major axis (2)
118-124 F7.5 AU E_a [3e-05/0.0548]? Upper uncertinty in a
126-132 F7.5 AU e_a [3e-05/0.0548]? Lower uncertinty in a
134-140 F7.1 --- Sinc [0.1/72599.2]? Incident stellar flux (2)
142-147 F6.1 --- E_Sinc [0/8785.5]? Upper uncertainty in Sinc
149-154 F6.1 --- e_Sinc [0/8785.5]? Lower uncertainty in Sinc
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Note (1): From Mullally et al. (2015, J/ApJS/217/31).
Note (2): Relative to Earth. Derived from the updated stellar properties
in Table 2.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- KOI Kepler Object of Interest identfier (K0NNNN.NN)
11- 17 F7.2 --- S/N [4.19/4012.61] Signal-to-noise ratio in i band
image
19- 23 F5.3 --- Pdet [0/1] Detection probability
25- 30 F6.4 --- Ptr [0.0016/0.3251] Transit probability
32- 41 F10.2 --- Weight [3.28/7117158.76] Weight, 1/wi (1)
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Note (1): wi is the product of the inverse pipeline detection efficiency
Pdet and the inverse transit probability Ptr for each detected planet.
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History:
From electronic version of the journal
References:
Petigura et al., Paper I 2017AJ....154..107P 2017AJ....154..107P, Cat. J/AJ/154/107
Johnson et al., Paper II 2017AJ....154..108J 2017AJ....154..108J, Cat. J/AJ/154/108
Fulton et al., Paper III 2017AJ....154..109F 2017AJ....154..109F, Cat. J/AJ/154/109
Petigura et al., Paper IV 2018AJ....155...89P 2018AJ....155...89P, Cat. J/AJ/155/89
Weiss et al., Paper V 2018AJ....155...48W 2018AJ....155...48W, Cat. J/AJ/155/48
Weiss et al., Paper VI 2018AJ....156..254W 2018AJ....156..254W
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 16-Apr-2019