J/AJ/156/277 Sixty validated planets from K2 campaigns 5-8 (Livingston+, 2018)
Sixty validated planets from K2 campaigns 5-8.
Livingston J.H., Crossfield I.J.M., Petigura E.A., Gonzales E.J.,
Ciardi D.R., Beichman C.A., Christiansen J.L., Dressing C.D., Henning T.,
Howard A.W., Isaacson H., Fulton B.J., Kosiarek M., Schlieder J.E.,
Sinukoff E., Tamura M.
<Astron. J., 156, 277 (2018)>
=2018AJ....156..277L 2018AJ....156..277L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Effective temperatures ;
Abundances, [Fe/H] ; Stars, masses ; Stars, diameters ;
Stars, distances
Keywords: planets and satellites: detection - techniques: photometric
Abstract:
We present a uniform analysis of 155 candidates from the second year
of NASA's K2 mission (Campaigns 5-8), yielding 60 statistically
validated planets spanning a range of properties with median values of
Rp=2.5 R⊕, P=7.1 days, Teq=811 K, and J=11.3 mag. The sample
includes 24 planets in 11 multiplanetary systems, as well as 18 false
positives and 77 remaining planet candidates. Of particular interest are
18 planets smaller than 2 R⊕, five orbiting stars brighter than
J=10 mag, and a system of four small planets orbiting the solar-type star
EPIC 212157262. We compute planetary transit parameters and false-positive
probabilities using a robust statistical framework and present a complete
analysis incorporating the results of an intensive campaign of
high-resolution imaging and spectroscopic observations. This work brings
the K2 yield to over 360 planets, and by extrapolation, we expect that
K2 will have discovered ∼600 planets before the expected depletion
of its onboard fuel in late 2018.
Description:
Our team successfully proposed K2 General Observer (GO) targets for
Campaigns 5-8. In brief, we used data from the TESS Dwarf Catalog
(Stassun et al. 2014arXiv1410.6379S 2014arXiv1410.6379S), the SUPERBLINK proper-motion database
(Lepine & Shara 2005AJ....129.1483L 2005AJ....129.1483L), the PanSTARRS-1 survey (Kaiser et al.
2002SPIE.4836..154K 2002SPIE.4836..154K; Chambers et al. 2016, Cat. II/349), 2MASS
(Cat. II/246), and WISE (Cat. II/311), applying color and proper-motion
cuts in order to select solar- and late-type dwarf stars while minimizing
contamination from background giants (for a more detailed description, see
Crossfield et al. 2016, J/ApJS/226/7 and Petigura et al. 2018, J/AJ/155/21,
hereafter P18). As the K2 data from all GO programs are public, we have
included data besides those from our own proposals in our search for
candidate planet transit signals.
From 2016 January 26 to 2017 August 20 UT, we performed high-resolution
imaging follow-up observations to identify stellar companions. We employed
adaptive optics (AO) techniques using the following near-infrared (NIR)
cameras: NIRC2 (Wizinowich et al. 2014SPIE.9148E..2BW) on the 10 m Keck II
telescope, PHARO (Hayward et al. 2001PASP..113..105H 2001PASP..113..105H) on the 5 m Hale
telescope, and NIRI on the 8 m Gemini North (Hodapp et al.
2003PASP..115.1388H 2003PASP..115.1388H).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 133 141 Target stars and parameters
table2.dat 233 155 Candidate parameters and dispositions
table3.dat 78 155 vespa likelihoods
table4.dat 31 32 Nearby bright AO sources
table5.dat 83 11 Improvement in orbital period estimates from
joint analysis of C5 and C16 light curves for
a subset of candidates
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJS/197/8 : Kepler's candidate multiple transiting planets
(Lissauer+, 2011)
J/ApJ/784/45 : Kepler's multiple planet candidates. III. (Rowe+, 2014)
J/ApJ/809/25 : Stellar and planet properties for K2 candidates (Montet+, 2015)
J/ApJS/222/14 : Planetary candidates from 1st yr K2 mission (Vanderburg+, 2016)
J/ApJS/226/7 : Planet candidates discovered using K2's 1st yr
(Crossfield+, 2016)
J/AJ/154/207 : K2 planetary systems orbiting low-mass stars (Dressing+, 2017)
J/ApJ/836/167 : K2 planetary syst. around low-mass stars. I. (Dressing+, 2017)
J/AJ/155/21 : Planet candidates from K2 campaigns 5-8 (Petigura+, 2018)
J/AJ/155/136 : Planets orbiting bright stars in K2 campaigns 0-10
(Mayo+, 2018)
J/AJ/156/78 : 44 validated planets from K2 Campaign 10 (Livingston+, 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 [211319617/220725183] EPIC identifier
11- 14 I4 K Teff [3398/6921] Effective temperature
16- 18 I3 K e_Teff [26/484] Uncertainty in Teff
20- 23 F4.2 [cm/s2] log(g) [0.55/4.92] Log surface gravity
25- 28 F4.2 [cm/s2] e_log(g) [0/0.16] Uncertainty in log(g)
30- 34 F5.2 [Sun] [Fe/H] [-0.54/0.39] Metallicity
36- 39 F4.2 [Sun] e_[Fe/H] [0.02/0.2] Uncertainty in [Fe/H]
41- 44 F4.2 Msun M* [0.33/2.29] Stellar mass
46- 49 F4.2 Msun e_M* [0.01/0.18] Uncertainty in M*
51- 56 F6.2 Rsun R* [0.33/133.86] Stellar radius
58- 62 F5.2 Rsun e_R* [0/14.8] Uncertainty in R*
64- 70 F7.2 pc Dist [34.62/2959.2] Distance
72- 77 F6.2 pc e_Dist [0.09/393.96] Uncertainty in Dist
79- 83 A5 --- Prov Provenance of basic parameters (1)
85-133 A49 --- GO K2 General Observer (GO) program(s)
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Note (1): Provenance of basic parameters are defined as follows (see Section 3.2
for more details):
SMsyn = SpecMatch-syn;
SMemp = SpecMatch-emp;
D17 = Dressing et al. (2017ApJ...836..167D 2017ApJ...836..167D);
M17 = Martinez et al. (2017ApJ...837...72M 2017ApJ...837...72M);
JHK = 2MASS (Cat. VII/233) photometry.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.2 --- Cand [211319617.01/220725183.01] Candidate identifier
14 I1 --- Field [5/8] K2 field number
16- 31 A16 --- Name Planet name
33- 41 F9.6 d Per [0.515013/30.951524] Period
43- 50 F8.6 d E_Per [1e-06/0.005554] Upper uncertainty in Per
52- 59 F8.6 d e_Per [1e-06/0.005201] Lower uncertainty in Per
61- 70 F10.5 d T0 [2307.47617/2580.72036] Epoch (BKJD)
72- 78 F7.5 d E_T0 [4e-05/0.01119] Upper uncertainty in T0
80- 86 F7.5 d e_T0 [4e-05/0.009] Lower uncertainty in TO
88- 92 F5.2 --- Rp/R* [1/59.71] Planet to stellar radius ratio
94- 98 F5.2 --- E_Rp/R* [0.03/20.01] Upper uncertainty in Rp/R*
100-104 F5.2 --- e_Rp/R* [0.02/13.53] Lower uncertainty in Rp/R*
106-111 F6.2 --- a/R* [1.32/139.64] Separation to stellar radius ratio
113-117 F5.2 --- E_a/R* [0.01/19.51] Upper uncertainty in a/R*
119-123 F5.2 --- e_a/R* [0.01/20.62] Lower uncertainty in a/R*
125-128 F4.2 --- b [0.09/1.17] Impact parameter
130-133 F4.2 --- E_b [0.01/0.36] Upper uncertainty in b
135-138 F4.2 --- e_b [0.01/0.48] Lower uncertainty in b
140-146 F7.2 Rgeo Rp [0.86/1904.12] Planet radius
148-153 F6.2 Rgeo e_Rp [0.06/786.22] Uncertainty in Rp
155-159 F5.2 AU a [1.14/20.34] Separation
161-164 F4.2 AU E_a [0.01/0.43] Upper uncertainty in a
166-169 F4.2 AU e_a [0.01/0.55] Lower uncertainty in a
171-174 I4 K Teq [318/6147] Equilibrium temperature
176-179 I4 K E_Teq [5/1882] Upper uncertainty in Teq
181-184 I4 K e_Teq [5/2174] Lower uncertainty in Teq
186-192 F7.3 Sun rho* [0.026/133.557] Stellar density in solar units
194-200 F7.3 Sun E_rho* [0.001/117.237] Upper uncertainty in rho*
202-207 F6.3 Sun e_rho* [0.001/73.087] Lower uncertainty in rho*
209-215 E7.2 --- FPP2 [0/1] False-positive probability
217-218 A2 --- Disp Disposition (1)
220-233 A14 --- Note Additional note(s) (2)
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Note (1): Disposition as follows:
VP = Validated planet;
PC = Planet candidate;
FP = False positive.
Note (2): Note as follows:
AO = Bright nearby star detected in AO;
Gaia = Bright star within K2 aperture detected in Gaia DR2 (Cat. I/345);
LR = Suspiciously large radius;
MS = Multi-system;
TTV = Flagged for transit timing variations (TTVs);
USP = Ultra-short period.
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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 --- Cand [211319617.01/220725183.01] Candidate identifier
14- 20 E7.2 --- Lbeb [0/0.0008] Likelihood that the signal is due to
a background eclipsing binary at the measured
period
22- 28 E7.2 --- LbebP2 [0/0.0055] Likelihood that the signal is due to
a background eclipsing binary at twice the
measured period
30- 37 E8.2 --- Leb [0/0.3] Likelihood that the signal is due to an
eclipsing binary at the measured period
39- 45 E7.2 --- LebP2 [1e-67/0.41] Likelihood that the signal is due to
an eclipsing binary at twice the measured period
47- 54 E8.2 --- Lheb [0/0.2]? Likelihood that the signal is due to
a hierarchical star system with an eclipsing
component at the measured period
56- 62 E7.2 --- LhebP2 [2.5e-95/0.022] Likelihood that the signal is due
to a hierarchical star system with an eclipsing
component at twice the measured period
64- 70 E7.2 --- Lpl [0/3.5] Likelihood that the signal is due to
a planet
72- 78 E7.2 --- FPP3 [0/1] False-positive probability
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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- 9 I9 --- EPIC [211413752/220555384] EPIC identifier of the
primary (1)
11- 15 F5.2 arcsec rho [0.2/13.55] Separation ρ
17- 19 F3.1 mag DKpmag [0.1/6.7] Differential Kepler magnitude
21- 24 F4.2 --- gamma1 [1/1.91] Dilution factor assuming the transit
signal comes from the primary star γpri
26- 31 F6.2 --- gamma2 [2.1/479.63] Dilution factor assuming the transit
signal comes from the secondary star γsec
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Note (1): Only AO sources bright enough to produce the observed transit-like
signals are listed.
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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- 12 F12.2 --- Cand [211490999.01/212164470.02] Candidate identifier
14- 24 F11.8 d PC5 [2.21928/30.9516] Orbital period estimate from
analysis of C5 light curves
26- 35 F10.8 d e_PC5 [7.9e-06/0.00332025] Lower limit uncertainty
in PC5
37- 46 F10.8 d E_PC5 [7.94e-06/0.00362482] Upper limit uncertainty
in PC5
48- 58 F11.8 d PC5+C16 [2.2192/30.9554] Orbital period estimate from
joint analysis of C5 and C16 light curves
60- 69 F10.8 d e_PC5+C16 [6.3e-07/0.00027763] Lower limit uncertainty
in PC5+C16
71- 80 F10.8 d E_PC5+C16 [6.3e-07/0.00021038] Upper limit uncertainty
in PC5+C16
82- 83 I2 --- Dprec [10/41] Factor by which the precision of the
period estimate is improved by C5+C16, as
compared to C5-only Δprec
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 23-Apr-2019