J/AJ/163/179 The California-Kepler Survey. X. (Petigura+, 2022)
The California-Kepler Survey.
X. The Radius Gap as a Function of Stellar Mass, Metallicity, and Age.
Petigura E.A., Rogers J.G., Isaacson H., Owen J.E., Kraus A.L., Winn J.N.,
MacDougall M.G., Howard A.W., Fulton B., Kosiarek M.R., Weiss L.M.,
Behmard A., Blunt S.
<Astron. J., 163, 179 (2022)>
=2022AJ....163..179P 2022AJ....163..179P
ADC_Keywords: Exoplanets; Stars, diameters; Stars, ages; Effective temperatures;
Stars, masses; Parallaxes, spectroscopic; Abundances, [Fe/H];
Spectra, optical
Keywords: Exoplanet astronomy ; Exoplanet formation ; Transit photometry ;
Exoplanets ; Super Earths ; Mini Neptunes ; High resolution
spectroscopy
Abstract:
In 2017, the California-Kepler Survey (CKS) published its first data
release (DR1) of high-resolution optical spectra of 1305 planet hosts.
Refined CKS planet radii revealed that small planets are bifurcated
into two distinct populations, super-Earths (smaller than 1.5R⊕)
and sub-Neptunes (between 2.0 and 4.0R⊕), with few planets in
between (the "radius gap"). Several theoretical models of the radius
gap predict variation with stellar mass, but testing these predictions
is challenging with CKS DR1 due to its limited M* range of
0.8-1.4M☉. Here we present CKS DR2 with 411 additional spectra and
derived properties focusing on stars of 0.5-0.8M☉. We found that
the radius gap follows Rp∝Pm with m=-0.10±0.03, consistent
with predictions of X-ray and ultraviolet- and core-powered mass-loss
mechanisms. We found no evidence that m varies with M*. We
observed a correlation between the average sub-Neptune size and
M*. Over 0.5-1.4M☉, the average sub-Neptune grows from 2.1 to
2.6R⊕, following Rp∝Mstarα with
α=0.25±0.03. In contrast, there is no detectable change for
super-Earths. These M*-Rp trends suggest that protoplanetary
disks can efficiently produce cores up to a threshold mass of Mc,
which grows linearly with stellar mass according to
Mc∼10M⊕(Mstar/M☉). There is no significant correlation
between sub-Neptune size and stellar metallicity (over -0.5 to
+0.5dex), suggesting a weak relationship between planet envelope
opacity and stellar metallicity. Finally, there is no significant
variation in sub-Neptune size with stellar age (over 1-10Gyr), which
suggests that the majority of envelope contraction concludes after
∼1Gyr.
Description:
We worked to compile a homogeneous spectroscopic catalog of all CKS
extended mass stars from new and archival observations. All spectra
were obtained with Keck/HIRES to ensure common systematics in our
analysis. Our goal was to gather spectra with R≥60000 and
S/N≥20/pixel on blaze at 5500Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 180 1716 Stellar properties
table2.dat 197 1246 Planet properties for the 888 star CXM sample
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VI/120 : High-resolution synthetic stellar library (Coelho+, 2005)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJ/767/95 : Improved stellar parameters of small KICstars (Dressing+, 2013)
J/ApJ/800/85 : Teff, radii and luminosities of cool dwarfs (Newton+, 2015)
J/ApJ/831/125 : ALMA 887µm obs. ChaI star-forming region (Pascucci+, 2016)
J/ApJ/825/19 : Mass-radius relationship planets with Rp<4 (Wolfgang+, 2016)
J/ApJ/836/167 : K2 planetary syst. around low-mass stars. I. (Dressing+, 2017)
J/AJ/154/109 : California-Kepler Survey. III. Planet radii (Fulton+, 2017)
J/ApJ/844/102 : KIC star parallaxes from asteroseismology/Gaia (Huber+, 2017)
J/ApJS/229/30 : Revised stellar properties Q1-17 Kepler targets (Mathur+, 2017)
J/AJ/154/107 : California-Kepler Survey (CKS). I. 1305 stars (Petigura+, 2017)
J/ApJ/836/77 : Library of high-S/N optical spectra of FGKM stars (Yee+, 2017)
J/ApJ/855/115 : Lithium abundances of KOIs from CKS spectra (Berger+, 2018)
J/ApJ/866/99 : Revised radii of KIC stars & planets, Gaia DR2 (Berger+, 2018)
J/AJ/156/264 : California-Kepler Survey VII. Planet radius gap (Fulton+, 2018)
J/AJ/155/205 : Occurrence rates Q1-Q16 KOI catalog planet cand. (Hsu+, 2018)
J/AJ/155/21 : Planet candidates from K2 campaigns 5-8 (Petigura+, 2018)
J/AJ/155/89 : California-Kepler Survey (CKS). IV. Planets (Petigura+, 2018)
J/ApJS/235/38 : Kepler planetary cand. VIII. DR25 reliability (Thompson+, 2018)
J/AJ/155/48 : California-Kepler Survey. V. Masses and radii (Weiss+, 2018)
J/ApJ/875/29 : Spectroscopic analysis of the CKS sample. I. (Martinez+, 2019)
J/AJ/160/108 : Gaia-Kepler stellar properties cat. II. Planets (Berger+, 2020)
J/AJ/159/280 : Gaia-Kepler stellar properties cat.I. KIC stars (Berger+, 2020)
J/AJ/160/239 : Cluster difference imaging photo. survey. II. (Bouma+, 2020)
J/AJ/159/211 : Exoplanets parameters from Kepler and K2 (Cloutier+, 2020)
J/AJ/161/265 : Compared rotation periods 1189 CKS host stars (David+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- KOI ? Kepler Object identifier
6- 24 I19 --- Gaia ? Gaia DR2 identifier
26- 30 F5.2 mag Ksmag [6.49/14.7] 2MASS Ks band magnitude
32- 35 F4.2 mag e_Ksmag [0.01/0.2]? Uncertainty in Ksmag
37- 41 F5.2 mas Gplx [-2.97/27.5]? Gaia DR2 parallax
43- 46 F4.2 mas e_Gplx [0.01/0.8]? Uncertainty in par
48- 51 I4 K Teff [3395/6662] Surface effective temperature
53- 55 I3 K e_Teff [70/110] Uncertainty for Teff
57- 61 F5.2 [-] FeH [-0.85/0.45] Metallicity
63- 66 F4.2 [-] e_FeH [0.06/0.09] Uncertainty for FeH
68- 72 F5.1 km/s vsini [0/180]? Projected rotational velocity (1)
74- 78 F5.2 Rsun rstar [0.36/11.8]? Adopted stellar radius,
Stefan-Boltzmann law
80- 83 F4.2 Rsun E_rstar [0.01/10]? Upper uncertainty on Rstar (2)
85- 89 F5.2 Rsun e_rstar [-5.5/-0.01]? Lower uncertainty on Rstar (2)
91- 94 F4.2 Msun Mstar [0/1.91]? Stellar mass (3)
96- 99 F4.2 Msun E_Mstar [0/0.5]? Upper uncertainty on Mstar (2)
101-105 F5.2 Msun e_Mstar [-0.8/0]? Lower uncertainty on Mstar (2)
107-111 F5.2 Rsun Rstar [0/11.2]? Stellar Radius (3)
113-116 F4.2 Rsun E_Rstar [0/4]? Upper uncertainty on Rstar (2)
118-122 F5.2 Rsun e_Rstar [-2/0]? Lower uncertainty on Rstar (2)
124-127 F4.2 g/cm3 rho [0/7.09]? Stellar density (3)
129-132 F4.2 g/cm3 E_rho [0/2]? Upper uncertainty on rho (2)
134-138 F5.2 g/cm3 e_rho [-2/0]? Lower uncertainty on rho (2)
140-143 F4.1 Gyr age [0/19.5]? Age, Gyr (3)
145-148 F4.1 Gyr E_age [0/12]? Upper uncertainty on age (2)
150-153 F4.1 Gyr e_age [-8/0]? Lower uncertainty on age (2)
155-159 F5.2 mas plx [0.08/33.1]? Spectroscopic parallax (3)
161-164 F4.2 mas E_plx [0.01/5]? Upper uncertainty on (2)
166-172 F7.2 mas e_plx [-193/-0.01]? Lower uncertainty on (2)
174-176 A3 --- prov Method for Teff, FeH, vsini values (4)
178-178 I1 --- SB2 [1/5] Limits on spectroscopic binaries (5)
180-180 I1 --- CXM [0/1] In the CKS Extended Mass subset?
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Note (1): vsini uncertainty is piecewise. If vsini>2 km/s, errors are 1km/s.
If vsini<2km/s, measurement should be interpreted as an upper limit
of vsini<2km/s.
Note (2): Stellar properties with the 'iso' subscript incorporate
constraints from the MIST isochrones.
Note (3): Median uncertainties are as follows:
e_Ksmag = 0.02mag
e_par = 1.4%
e_Teff = 100K;
e_FeH = 0.06dex
e_vsini = 1km/s
e_Rstar = 3.9%
e_Mstar-iso = 3.7%
e_Rstar-iso = 2.6%
e_rho-iso = 8.9%
e_age-iso = 0.24dex
e_par-spec = 16%
Note (4): Methods as follows :
syn = SpecMatch-Synthetic
emp = SpecMatch-Empirical
Note (5): Limit as follows :
1 = No detection of SB2 with V band magnitude difference ~<5mag and
radial velocity differences ≳12km/s
2 = T<3500K, star unfit for ReaMatch;
3 = vsini>10km/s, star unfit for ReaMatch;
4 = Ambiguous detection;
5 = Obvious detection.
SB2 encodes the limits on spectroscopic binaries (SB2s) using the
ReaMatch code (Kolbl+, 2015AJ....149...18K 2015AJ....149...18K). Note: ReaMatch
computes Teff and vsini independently from SpecMatch-Synthetic and
SpecMatch-Empirical.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Planet Planet identifier
11- 22 F12.8 d Per [0.25/506] Orbital Period (1)
24- 33 F10.8 d E_Per [3e-08/0.03] Upper uncertainty on Per (1)
35- 45 F11.8 d e_Per [-0.03/-3e-08] Lower uncertainty on Per (1)
47- 54 F8.3 % Rp/Rs [0.4/7469] Ratio, Planet to Star Radius (1)
56- 63 F8.3 % E_Rp/Rs [0.001/2251] Upper uncertainty on Rp/Rstar (1)
65- 73 F9.3 % e_Rp/Rs [-2251/-0.001] Lower uncertainty on Rp/Rstar (1)
75- 81 F7.4 h T [0.37/22.5]? Transit duration, hours (1)
83- 88 F6.4 h E_T [0.0004/7]? Upper uncertainty on T (1)
90- 96 F7.4 h e_T [-7/-0.0004]? Lower uncertainty on T (1)
98-104 F7.2 Rgeo Rp [0.41/6063] Planet Radius from Rp/Rs and Rstar
106-112 F7.2 Rgeo E_Rp [0.03/2347] Upper uncertainty on Rp
114-121 F8.2 Rgeo e_Rp [-2347/-0.03] Lower uncertainty on Rp
123-129 F7.4 h Tmax [0.86/24.1] Expected duration of a centrally
transiting object on a circular orbit
131-136 F6.4 h E_Tmax [0.02/0.8] Upper uncertainty on Tmax
138-144 F7.4 h e_Tmax [-0.8/-0.02] Lower uncertainty on Tmax
146-151 F6.4 au a [0.006/1.15] semi-major axis, au (2)
153-158 F6.4 au E_a [0.0001/0.02] Upper uncertainty on a (2)
160-166 F7.4 au e_a [-0.02/-0.0001] Lower uncertainty on a (2)
168-176 F9.4 --- S [0.14/5949] Incident bolometric flux, Earth unit
(2)
178-185 F8.4 --- E_S [0.01/609] Upper uncertainty on S (2)
187-195 F9.4 --- e_S [-609/-0.01] Lower uncertainty on S (2)
197-197 I1 --- Samp [0/1] In curated list of 970 planets; Section 5
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Note (1): measured from Kepler photometry by Thompson+, 2018 J/ApJS/235/38.
Note (2): determined from Kepler's Third Law and the Stefan-Boltzmann law.
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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 Cat. J/AJ/156/254
Fulton et al. Paper VII : 2018AJ....156..264F 2018AJ....156..264F Cat. J/AJ/156/264
Mills et al. Paper VIII : 2019AJ....157..198M 2019AJ....157..198M
Dai et al. Paper IV : 2020AJ....159..247D 2020AJ....159..247D
(End) Prepared by [AAS], Coralie Fix [CDS], 02-May-2022