J/MNRAS/496/851 Planet candidates from K2 Campaigns 1-13 (Wittenmyer+, 2020)
K2-HERMES II. Planet-candidate properties from K2 Campaigns 1-13.
Wittenmyer R.A., Clark J.T., Sharma S., Stello D., Horner J., Kane S.R.,
Stevens C.P., Wright D.J., Spina L., Cotar K., Asplund M.,
Bland-Hawthorn J., Buder S., Casey A.R., De Silva G.M., D'Orazi V.,
Freeman K., Kos J., Lewis G., Lin J., Lind K., Martell S.L., Simpson J.D.,
Zucker D.B., Zwitter T.
<Mon. Not. R. Astron. Soc., 496, 851-863 (2020)>
=2020MNRAS.496..851W 2020MNRAS.496..851W (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Stars, fundamental ; Effective temperatures ;
Stars, masses ; Stars, diameters ; Spectra, optical
Keywords: techniques: spectroscopic -
planets and satellites: fundamental parameters -
stars: fundamental parameters
Abstract:
Accurate and precise radius estimates of transiting exoplanets are
critical for understanding their compositions and formation
mechanisms. To know the planet, we must know the host star in as much
detail as possible. We present complete results for planet-candidate
hosts from the K2-HERMES survey, which uses the HERMES multi-object
spectrograph on the Anglo-Australian Telescope to obtain R∼28000
spectra for more than 30000 K2 stars. We present complete host-star
parameters and planet-candidate radii for 224 K2 candidate planets
from C1-C13. Our results cast severe doubt on 30 K2 candidates, as we
derive unphysically large radii, larger than 2RJup. This work
highlights the importance of obtaining accurate, precise, and
self-consistent stellar parameters for ongoing large planet search
programs - something that will only become more important in the
coming years, as TESS begins to deliver its own harvest of exoplanets.
Description:
Target selection for the K2-HERMES program is described fully in our
previous work (Wittenmyer et al. 2018AJ....155...84W 2018AJ....155...84W; Sharma et al.
2019MNRAS.490.5335S 2019MNRAS.490.5335S). For this study, we selected all K2 planet
candidate host stars which had been observed in the K2-HERMES program.
We find 199 stars hosting 224 K2 planet candidates for which K2-HERMES
spectra are available. The reduction and analysis procedures are
identical to those of the GALAH and TESS-HERMES surveys, as described
fully in Kos et al. (2017MNRAS.464.1259K 2017MNRAS.464.1259K), Buder et al.
(2018MNRAS.478.4513B 2018MNRAS.478.4513B, Cat. J/MNRAS/478/4513), and Sharma et al.
(2018MNRAS.473.2004S 2018MNRAS.473.2004S, Cat. J/MNRAS/473/2004).
With a self-consistent set of spectroscopic parameters in hand
(Teff, logg, [Fe/H]), we derived the stellar physical parameters
using the ISOCHRONES Python package (Morton 2015ascl.soft03010M).
ISOCHRONES is a Bayesian isochronic modeller that determines the mass,
radius, and age of stars given various photometric and spectroscopic
inputs using MESA Isochrones & Stellar Tracks (MIST) (Dotter
2016ApJS..222....8D 2016ApJS..222....8D) grids. For our analysis, we used the effective
temperature (Teff), surface gravity (logg), 2MASS (H, J, Ks)
(Skrutskie et al. 2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233), and Gaia (G,
GRP, GBP) photometric magnitudes along with parallax values
obtained by Gaia DR2 (Gaia Collaboration 2018A&A...616A...1G 2018A&A...616A...1G, Cat.
I/345) where available.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 72 3 Stellar parameters derived from seismology, and
comparison with the spectroscopic results from
K2-HERMES
table2.dat 68 199 Spectroscopic and derived stellar parameters
table3.dat 62 224 Planetary insolation and Habitable Zone
boundaries
table4.dat 103 224 Planet-candidate properties
table5.dat 86 30 Candidates larger than 22R⊕. These
candidates are highly likely to be false
positives
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See also:
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- EPIC EPIC identifier
11- 15 F5.3 [cm/s2] loggs Surface gravity derived from seismology
17- 21 F5.3 [cm/s2] e_loggs Error on loggs
23- 26 F4.2 Rsun Rads Star radius derived from seismology
28- 31 F4.2 Rsun e_Rads Error on Rads
33- 36 F4.2 Msun Masss Mass radius derived from seismology
38- 41 F4.2 Msun e_Masss Error on Masss
43- 46 F4.2 [cm/s2] loggK Surface gravity derived from K2-HERMES
spectroscopy
48- 51 F4.2 [cm/s2] e_loggK Error on loggK
53- 57 F5.2 Rsun RadK Star radius derived from K2-HERMES
spectroscopy
59- 62 F4.2 Rsun e_RadK Error on RadK
64- 67 F4.2 Msun MassK Mass radius derived from K2-HERMES
spectroscopy
69- 72 F4.2 Msun e_MassK Error on MassK
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- EPIC EPIC identifier
11- 16 F6.1 K Teff Effective temperature
18- 22 F5.1 K e_Teff Error on Teff
24- 27 F4.2 [cm/s2] logg Surface gravity
29- 32 F4.2 [cm/s2] e_logg Error on logg
34- 38 F5.2 [-] [Fe/H] Fe/H abundance ratio
40- 43 F4.2 [-] e_[Fe/H] Error on [Fe/H]
45- 49 F5.3 Msun Mass Star mass
51- 55 F5.3 Msun e_Mass Error on Mass
57- 62 F6.3 Rsun Rad Radius mass
64- 68 F5.3 Rsun e_Rad Error on Rad
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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- 12 F12.2 --- EPIC EPIC identifier
14- 22 F9.1 Sun Flux Incident flux received by the planet in units of
the solar constant
24- 30 F7.1 K Teqhd Equilibrium temperature using 'hot dayside'
model
32- 38 F7.1 K Teqwm Equilibrium temperature using 'well-mixed' model
40- 44 F5.2 AU HZio Habitable Zone inner optimistic boundary (1)
46- 50 F5.2 AU HZic Habitable Zone inner conservative boundary (1)
52- 56 F5.2 AU HZoc Habitable Zone outer optimistic boundary (1)
58- 62 F5.2 AU HZoo Habitable Zone outer conservative boundary (1)
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Note (1): We calculated the HZ boundaries for each of the stars, using the
formalism described by Kopparapu et al. (2013ApJ...765..131K 2013ApJ...765..131K,
2014ApJ...787L..29K 2014ApJ...787L..29K, Cat. J/ApJ/787/L29). We calculated the 'runaway
greenhouse' and 'maximum greenhouse' boundaries (referred to as the
'conservative' HZ) and the empirically derived 'recent Venus' and
'early Mars' boundaries (referred to as the 'optimistic' HZ). A
thorough description of these boundaries and how they are used is
provided by Kane et al. (2016ApJ...830....1K 2016ApJ...830....1K).
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- EPIC EPIC identifier
14- 21 A8 --- K2 K2 identifier
23- 24 I2 --- Ref [1/13] Reference (1)
26- 36 F11.8 d P Orbital period from the NASA Exoplanet Archive
38- 46 F9.7 d e_P ? Error on P
48- 54 F7.5 AU a Semimajor axis (2)
56- 62 F7.5 AU e_a Error on a
64- 71 F8.6 --- Rp/R* Planet radius to star radius ratio from the NASA
Exoplanet Archive
73- 80 F8.6 --- E_Rp/R* ? Upper error on Rp/R*
82- 89 F8.6 --- e_Rp/R* ? Lower error on Rp/R*
91- 96 F6.2 Rgeo Rp Planet radius (3)
98- 103 F6.2 Rgeo e_Rp Error on Rp
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Note (1): Reference as follows:
1 = Mayo et al. (2018AJ....155..136M 2018AJ....155..136M, Cat. J/AJ/155/136)
2 = Livingston et al. (2018AJ....156...78L 2018AJ....156...78L, Cat. J/AJ/156/78)
3 = Crossfield et al. (2016ApJS..226....7C 2016ApJS..226....7C, Cat. J/ApJS/226/7)
4 = Adams, Jackson & Endl (2016AJ....152...47A 2016AJ....152...47A)
5 = Vanderburg et al. (2016ApJS..222...14V 2016ApJS..222...14V, Cat. J/ApJS/222/14)
6 = Schmitt et al. (2016AJ....151..159S 2016AJ....151..159S)
7 = Zink et al. (2019RNAAS...3...43Z 2019RNAAS...3...43Z)
8 = Pope, Parviainen & Aigrain (2016MNRAS.461.3399P 2016MNRAS.461.3399P)
9 = Dressing et al. (2017AJ....154..207D 2017AJ....154..207D, Cat. J/AJ/154/207)
10 = Nardiello et al. (2016MNRAS.463.1831N 2016MNRAS.463.1831N, Cat. J/MNRAS/463/1831)
11 = Petigura et al. (2017AJ....153..142P 2017AJ....153..142P, Cat. J/AJ/153/142)
12 = Mann et al. (2017AJ....153...64M 2017AJ....153...64M)
13 = Kruse et al. (2019ApJS..244...11K 2019ApJS..244...11K, Cat. J/ApJS/244/11)
Note (2): The semimajor axis values have been recalculated based on the orbital
period and the revised stellar masses given in Table 2
Note (3): We derived the planet-candidate radii by multiplying Rp/R* by the
stellar radii obtained by isochrones as described above
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- EPIC EPIC identifier
11- 16 F6.2 Rgeo Rp Planet radius
18- 23 F6.2 Rgeo e_Rp Error on Rp
25- 86 A62 --- Comments Comments
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History:
From electronic version of the journal
References:
Wittenmyer et al., Paper I 2018AJ....155...84W 2018AJ....155...84W
(End) Ana Fiallos [CDS] 28-Jun-2023