J/ApJ/890/23 NUV and FUV measurements of planet host stars (Loyd+, 2020)
Current population statistics do not favor photoevaporation over core-powered
mass loss as the dominant cause of the exoplanet radius gap.
Loyd R.O.P., Shkolnik E.L., Schneider A.C., Richey-Yowell T., Barman T.S.,
Peacock S., Pagano I.
<Astrophys. J., 890, 23-23 (2020)>
=2020ApJ...890...23L 2020ApJ...890...23L (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets; Stars, masses; Photometry, ultraviolet;
Stars, diameters
Keywords: Exoplanet evolution; Exoplanet catalogs; Stellar activity
Abstract:
We search for evidence of the cause of the exoplanet radius gap, i.e.,
the dearth of planets with radii near 1.8R⊕. If the cause were
photoevaporation, the radius gap should trend with proxies for the
early-life high-energy emission of the planet-hosting stars. If,
alternatively, the cause were core-powered mass loss, no such trends
should exist. Critically, spurious trends between the radius gap and
stellar properties arise from an underlying correlation with
instellation. After accounting for this underlying correlation, we
find that no trends remain between the radius gap and stellar mass or
present-day stellar activity as measured by near-UV emission. We
dismiss the nondetection of a radius gap trend with near-UV emission
because present-day near-UV emission is unlikely to trace early-life
high-energy emission, but we provide a catalog of Galaxy Evolution
Explorer near-UV and far-UV emission measurements for general use. We
interpret the nondetection of a radius gap trend with stellar mass by
simulating photoevaporation with mass-dependent evolution of stellar
high-energy emission. The simulation produces an undetectable trend
between the radius gap and stellar mass under realistic sources of
error. We conclude that no evidence, from this analysis or others in
the literature, currently exists that clearly favors either
photoevaporation or core-powered mass loss as the primary cause of the
exoplanet radius gap. However, repeating this analysis once the body
of well-characterized <4R⊕ planets has roughly doubled could
confirm or rule out photoevaporation.
Description:
The population of planets we analyzed consists of the confirmed and
Kepler candidate exoplanet systems downloaded from the NASA Exoplanet
Archive on 2019 June 7. We updated system parameters to those of the
California Kepler Survey (Fulton & Petigura 2018, J/AJ/156/264) and
the asteroseismic survey of Van Eylen+ (2018MNRAS.479.4786V 2018MNRAS.479.4786V) where
possible.
GALEX observed nearly the entire sky during its operation from 2003 to
2012. The observatory conducted photometry in two broad UV bands: an
FUV band covering roughly 1350-1800Å, and an NUV band covering
roughly 1700-3000Å. We obtained NUV and FUV fluxes of the host
stars, or upper limits, from the GALEX master source catalog hosted by
the Mikulski Archive for Space Telescopes (MAST). See Section 2.1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 499 6393 Host star GALEX fluxes and planetary irradiations
for all known planetary systems
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
II/335 : Revised catalog of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/MNRAS/422/2024 : X-ray-age relation & exoplanet evaporation (Jackson+, 2012)
J/ApJ/766/9 : GALEX observations of exoplanet host stars (Shkolnik, 2013)
J/ApJ/780/159 : Rotation-mass-ages of old field stars (Epstein+, 2014)
J/AJ/148/64 : HAZMAT. I. FUV & NUV in early M stars (Shkolnik+, 2014)
J/AJ/154/109 : California-Kepler Survey. III. Planet radii (Fulton+, 2017)
J/ApJ/848/34 : CATalog of Stellar Unified Properties (Hinkel+, 2017)
J/AJ/155/122 : HAZMAT. III. Low-mass stars GALEX photometry (Schneider+, 2018)
J/AJ/156/264 : CKS. VII. Planet radius gap (Fulton+, 2018)
J/ApJ/872/17 : HAZMAT. V. UV & X evolution of K stars (Richey-Yowell+, 2019)
J/ApJ/875/29 : Spectroscopic analysis of the CKS sample. I. (Martinez+, 2019)
http://archive.stsci.edu/galexView/ : GalexView home page
http://exoplanetarchive.ipac.caltech.edu/ : NASA exoplanet archive
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 30 A30 --- ID Planet identifier
32- 58 A27 --- Host Host identifier
60- 66 E7.1 mW/m2 NUV [1e-16/9e-10]?=0 Observed GALEX NUV band
flux (1)
68- 74 E7.1 mW/m2 e_NUV [9.6e-16/1.5e-12]?=0 Lower uncertainty in
NUV (1)
76- 82 E7.1 mW/m2 E_NUV [9.6e-16/1.5e-12]?=0 Upper uncertainty in
NUV (1)
84- 85 I2 --- l_NUV [-1/1]?=0 Limit flag on NUV (2)
87- 93 E7.1 mW/m2 NUVp [1e-7/2.9e+10]?=0 NUV band flux at planet (1)
95- 101 E7.1 mW/m2 e_NUVp [3.3e-7/2.6e+9]?=0 Lower uncertainty in NUVp
(1)
103- 109 E7.1 mW/m2 E_NUVp [3.3e-7/2.6e+9]?=0 Upper uncertainty in NUVp
(1)
111- 112 I2 --- l_NUVp [-1/1]?=0 Limit flag on NUVp (2)
114- 121 A8 mW/m2 ExNUV Excess NUV band flux at planet (1)(3)
123- 130 A8 mW/m2 e_ExNUV Lower uncertainty in ExNUV (1)
132- 139 A8 mW/m2 E_ExNUV Upper uncertainty in ExNUV (1)
141- 142 I2 --- l_ExNUV [-1/1]?=0 Limit flag on ExNUV (2)
144- 150 E7.1 mW/m2 FUV [8.4e-17/2.5e-10]?=0 Observed GALEX FUV band
flux (1)
152- 158 E7.1 mW/m2 e_FUV [9.5e-16/6.5e-13]?=0 Lower uncertainty in
FUV (1)
160- 166 E7.1 mW/m2 E_FUV [9.5e-16/6.5e-13]?=0 Upper uncertainty in
FUV (1)
168- 169 I2 --- l_FUV [-1/1]?=0 Limit flag on FUV (2)
171- 177 E7.1 mW/m2 FUVp [1.5e-7/5e+9]?=0 FUV band flux at planet (1)
179- 185 E7.1 mW/m2 e_FUVp [1.6e-7/2.8e+7]?=0 Lower uncertainty in FUVp
(1)
187- 193 E7.1 mW/m2 E_FUVp [1.6e-7/2.8e+7]?=0 Upper uncertainty in FUVp
(1)
195 I1 --- l_FUVp [1]?=0 Upper limit flag on FUVp (2)
197- 204 A8 mW/m2 ExFUV Excess FUV band flux at planet (values between
-9.1e+97 and 5e+09) (1)(3)
206- 213 A8 mW/m2 e_ExFUV Lower uncertainty in ExFUV (1)
215- 222 A8 mW/m2 E_ExFUV Upper uncertainty in ExFUV (1)
224 I1 --- l_ExFUV [1]?=0 Upper limit flag on ExFUV (2)
226- 242 F17.9 d Per [0.09/7.3e+6]?=0 Orbital period
244- 250 E7.1 d e_Per [1e-8/3.6e+6]?=0 Lower uncertainty in Per
252- 258 E7.1 d E_Per [1e-8/3.6e+6]?=0 Upper uncertainty in Per
260- 261 I2 --- l_Per [-1]?=0 Lower limit flag on Per (2)
263- 281 A19 --- r_Per Bibcode reference for Per
283- 292 E10.4 Earth S [1.97e-6/636430]?=0 Instellation (4)
294- 303 E10.4 Earth e_S [1.2e-7/86461]?=0 Lower uncertainty in S
305- 314 E10.4 Earth E_S [1.2e-7/86461]?=0 Upper uncertainty in S
316 I1 --- l_S [0]?=0 Limit flag on S (always NULL)
318- 336 A19 --- r_S Bibcode reference for S
338- 343 F6.3 Msun Mass [0.01/23.6]?=0 Stellar mass
345- 350 F6.3 Msun e_Mass [0.002/97.1]?=0 Lower uncertainty in Mass
352- 357 F6.3 Msun E_Mass [0.002/97.1]?=0 Upper uncertainty in Mass
359 I1 --- l_Mass [0]?=0 Limit flag on Mass (always NULL)
361- 379 A19 --- r_Mass Bibcode reference for Mass
381- 386 F6.3 [Lsun] L* [-6.1/6.1] Log stellar luminosity
388- 392 F5.3 [Lsun] e_L* [0/1] Lower uncertainty in L*
394- 398 F5.3 [Lsun] E_L* [0/1.5] Upper uncertainty in L*
400 I1 --- l_L* [0]?=0 Limit flag on L* (always NULL)
402- 420 A19 --- r_L* Bibcode reference for L*
422- 427 F6.3 Earth Rp [0.2/96.1]?=0 Planet radius
429- 434 F6.3 Earth e_Rp [0.008/54.6]?=0 Lower uncertainty in Rp
436- 441 F6.3 Earth E_Rp [0.008/54.6]?=0 Lower uncertainty in Rp
443- 444 I2 --- l_Rp [-1/1]?=0 Limit flag on Rp (2)
446- 464 A19 --- r_Rp Bibcode reference for Rp
466- 470 F5.2 --- b [0/1] Transit impact parameter; unitless (5)
472- 476 F5.2 --- e_b [0/0.76] Lower uncertainty in b
478- 482 F5.2 --- E_b [0/0.7] Lower uncertainty in b
484 I1 --- l_b [1]?=0 Upper limit flag on b (2)
486- 489 F4.2 [cm/s2] logg [0/5.52] Log stellar surface gravity (5)
491- 494 F4.2 [cm/s2] e_logg [0/3.6] Lower uncertainty in logg
496- 499 F4.2 [cm/s2] E_logg [0/0.6] Lower uncertainty in logg
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Note (1): In units of erg/s/cm2.
Note (2): Limit flag as follows:
-1 = Value is a lower limit.
1 = Value is an upper limit.
Note (3): Flux remaining after the subtraction of an empirical estimate
of the flux from the star's photosphere.
Note (4): Instellation is the bolometric flux of the star at the planet.
Note (5): These values are from the NASA Exoplanet Catalog confirmed and Kepler
candidate tables retrieved 2019 June 7. References are uncertain and
so have been excluded.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Jul-2021