J/ApJ/771/107 Spectroscopy of faint KOI stars (Everett+, 2013)
Spectroscopy of faint Kepler mission exoplanet candidate host stars.
Everett M.E., Howell S.B., Silva D.R., Szkody P.
<Astrophys. J., 771, 107 (2013)>
=2013ApJ...771..107E 2013ApJ...771..107E
ADC_Keywords: Planets ; Stars, double and multiple ; Stars, diameters ;
Abundances, [Fe/H]
Keywords: planetary systems; planets and satellites: fundamental parameters;
stars: fundamental parameters; surveys
Abstract:
Stellar properties are measured for a large set of Kepler mission
exoplanet candidate host stars. Most of these stars are fainter than
14th magnitude, in contrast to other spectroscopic follow-up studies.
This sample includes many high-priority Earth-sized candidate planets.
A set of model spectra are fitted to R∼3000 optical spectra of 268
stars to improve estimates of Teff, log(g), and [Fe/H] for the
dwarfs in the range 4750≤Teff≤7200K. These stellar properties are
used to find new stellar radii and, in turn, new radius estimates for
the candidate planets. The result of improved stellar characteristics
is a more accurate representation of this Kepler exoplanet sample and
identification of promising candidates for more detailed study. This
stellar sample, particularly among stars with Teff≳5200K, includes
a greater number of relatively evolved stars with larger radii than
assumed by the mission on the basis of multi-color broadband
photometry. About 26% of the modeled stars require radii to be revised
upward by a factor of 1.35 or greater, and modeling of 87% of the
stars suggest some increase in radius. The sample presented here also
exhibits a change in the incidence of planets larger than
3-4R⊕ as a function of metallicity. Once [Fe/H] increases to
≥-0.05, large planets suddenly appear in the sample while smaller
planets are found orbiting stars with a wider range of metallicity.
Description:
We observed KOIs in the Kepler field (115deg2 centered at
α=19h25, δ=+44.5°) on 48 nights during 2010-2012 using
the National Optical Astronomy Observatory (NOAO) Mayall 4m telescope
on Kitt Peak and the facility RCSpec long-slit spectrograph.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 45 368 Stellar properties determined for 352 KOIs
table3.dat 51 363 Data used in Figures 8-10 for the planet
candidates of 215 stars
--------------------------------------------------------------------------------
See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
VI/120 : High-resolution synthetic stellar library (Coelho+, 2005)
J/ApJS/213/5 : Cool KOIs. VI. H- and K- band spectra (Muirhead+, 2014)
J/ApJS/211/2 : Revised properties of Q1-16 Kepler targets (Huber+, 2014)
J/ApJS/210/20 : Small Kepler planets radial velocities (Marcy+, 2014)
J/ApJS/210/19 : Kepler planetary candidates. IV. 22 months (Burke+, 2014)
J/ApJS/210/1 : Asteroseismic study of solar-type stars (Chaplin+, 2014)
J/ApJ/770/69 : Kepler planet candidates radii (Petigura+, 2013)
J/ApJ/770/43 : Spectroscopic [Fe/H] of Kepler planet hosts (Mann+, 2013)
J/ApJ/767/95 : Improved stellar param. of KIC stars (Dressing+, 2013)
J/ApJ/750/L37 : Stellar parameters of low-mass KOIs (Muirhead+, 2012)
J/ApJS/199/30 : Effective temperature for KIC stars (Pinsonneault+, 2012)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/MNRAS/423/122 : Abundances of 93 solar-type Kepler targets (Bruntt+, 2012)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJ/738/170 : False positive Kepler planet candidates (Morton+, 2011)
J/ApJ/704/1107 : Transiting planets in HATNet field 205 (Latham+, 2009)
J/AJ/133/2464 : Parameters and abundances of nearby giants (Luck+, 2007)
J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)
http://exoplanetarchive.ipac.caltech.edu/ : NASA exoplanet archive
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- KOI [13/3259] Kepler Object of Interest number
6- 13 I8 --- KIC Kepler identifier
15- 20 F6.3 mag Kpmag [9.5/16.5] Observed Kepler magnitude
22- 25 I4 K Teff [4750/6606]? Effective temperature (1)
27- 30 F4.2 [cm/s2] log(g) [4/4.7]? Log of the surface gravity (2)
32- 36 F5.2 [Sun] [Fe/H] [-0.3/0.3]? Metallicity (3)
38- 41 F4.2 Rsun R* [0.7/2]? Stellar radius (4)
43- 45 A3 --- n_KOI [a-g, ] Additional note(s) on KOI (5)
--------------------------------------------------------------------------------
Note (1): Uncertainty in Teff is ±75K.
Note (2): Uncertainty in log(g) is ±0.15.
Note (3): Uncertainty in [Fe/H] is ±0.10.
Note (4): Uncertainty in R* is ±0.05RSun.
Note (5): Note as follows:
a = Teff<4750K;
b = Teff>7200K;
c = log(g)<4.00 and 5500K≤Teff≤7200K;
d = log(g)<4.15 and 4750K≤Teff<5500K;
e = [Fe/H]←0.25;
f = model fit reached a parameters limit;
g = Now known to be a false positive.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [K0]
3- 9 F7.2 --- KOI Planet identifier (<KOI-NNNN.NN> in Simbad)
11- 18 I8 --- KIC Kepler parent star identifier
20- 24 F5.3 [K] log(Teff) [3.6/3.9] Log of the effective temperature
26- 29 F4.2 [cm/s2] log(g) [4/4.7] Log of the surface gravity
31- 35 F5.2 [Sun] [Fe/H] [-0.3/0.3] Metallicity
37- 40 F4.2 Rsun R* [0.7/2] Stellar radius
42- 45 F4.2 --- Ratio [0.5/2.2] Ratio of revised to KSAS derived
stellar radii (1)
47- 51 F5.2 Rgeo Rp [0.4/59] Planetary radius; Earth radii
--------------------------------------------------------------------------------
Note (1): Kepler Science Analysis System (KSAS) was a Kepler mission database
storing the best available estimates for stellar and candidate planet
properties. Stellar radii were based on KIC photometry for most stars
in the magnitude range of interest here.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Jan-2015