J/ApJ/750/L37 Stellar parameters of low-mass KOIs (Muirhead+, 2012)
Characterizing the cool Kepler objects of interests. New effective temperatures,
metallicities, masses, and radii of low-mass Kepler planet-candidate host stars.
Muirhead P.S., Hamren K., Schlawin E., Rojas-Ayala B., Covey K.R.,
Lloyd J.P.
<Astrophys. J., 750, L37 (2012)>
=2012ApJ...750L..37M 2012ApJ...750L..37M
ADC_Keywords: Stars, double and multiple ; Spectroscopy ; Planets ;
Effective temperatures ; Stars, masses ; Stars, diameters
Keywords: planetary systems - stars: abundances -
stars: fundamental parameters - stars: late-type - stars: low-mass
Abstract:
We report stellar parameters for late-K and M-type planet-candidate
host stars announced by the Kepler Mission. We obtained
medium-resolution, K-band spectra of 84 cool (Teff≲4400K) Kepler
Objects of Interest (KOIs) from Borucki et al (2011,
Cat. J/ApJ/728/117). We identified one object as a giant (KOI 977);
for the remaining dwarfs, we measured effective temperatures (Teff)
and metallicities [M/H] using the K-band spectral indices of
Rojas-Ayala et al (2012, Cat. J/ApJ/748/93). We determine the masses
(M*) and radii (R*) of the cool KOIs by interpolation onto the
Dartmouth evolutionary isochrones. The resultant stellar radii are
significantly less than the values reported in the Kepler Input
Catalog and, by construction, correlate better with Teff. Applying
the published KOI transit parameters to our stellar radius
measurements, we report new physical radii for the planet candidates.
Recalculating the equilibrium temperatures of the planet-candidates
assuming Earth's albedo and re-radiation fraction, we find that three
of the planet-candidates are terrestrial sized with orbital semimajor
axes that lie within the habitable zones of their host stars
(KOI 463.01, KOI 812.03, and KOI 854.01).
Description:
Observations were carried out with the TripleSpec Spectrograph at the
Palomar Observatory 200 inch Hale Telescope. TripleSpec is a
near-infrared slit-spectrograph covering 1.0-2.5um simultaneously with
a resolution of 2700. We observed all of the KOIs with KIC-ascribed
effective temperatures less than 4400K over seven nights in 2011 June.
In 2011 August we observed 15 additional KOIs with KIC-ascribed Teff
greater than 4400K, but with colors indicative of low-mass stars:
(J-K)>0.7, (r-i)>0.3, or (g-r)>1.0.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 126 116 Cool KOI stellar host and planet-candidate properties
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/A+A/557/A70 : Evolved planet hosts - stellar parameters (Mortier+, 2013)
J/A+A/556/A150 : SWEETCat I. Stellar parameters for host stars (Santos+, 2013)
J/ApJ/748/93 : K-band spectra for 133 nearby M dwarfs (Rojas-Ayala+, 2012)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/ApJ/736/L25 : Habitability of Kepler planetary cand. (Kaltenegger+, 2011)
J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)
J/ApJ/732/55 : Abundances of stars with planets (Schuler+, 2011)
J/ApJ/728/117 : Kepler planetary candidates. I. (Borucki+, 2011)
J/A+A/487/373 : Spectroscopic parameters of 451 HARPS-GTO stars (Sousa+, 2008)
J/A+A/415/1153 : [Fe/H] for 98 extra-solar planet-host stars (Santos+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 --- KOI KOI (Kepler Objects of Interest) Number
9- 20 F12.8 d Per [0.4/234] Transit Period (1)
22- 31 F10.7 d e_Per Error in Per
33- 37 F5.3 --- Rp/R* [0/0.3] Ratio planet to star radius (1)
39- 45 F7.5 --- e_Rp/R* Error in Rp/R*
47- 50 I4 K Teff [3203/5189] Star Effective Temperature (2)
52- 55 I4 K E_Teff Positive error in Teff
57- 59 I3 K e_Teff Negative error in Teff
61- 65 F5.2 [Sun] M/H [-0.4/0.4] Overall Metallicity (2)
67- 70 F4.2 [Sun] e_M/H Error in M/H
72- 74 A3 --- SpT MK spectral type (2)
76- 79 F4.2 Msun M* [0.1/0.8] Star Mass (3)
81- 84 F4.2 Msun e_M* Error in M*
86- 89 F4.2 Rsun R* [0.1/0.8] Star Radius (3)
91- 94 F4.2 Rsun e_R* Error in R*
96-102 F7.5 AU a [0.005/0.7] Planet semi-major axis (4)
104-110 F7.5 AU e_a Error in a
112-116 F5.2 Rgeo Rp [0/14.5] Planetary Radius (4)
118-121 F4.2 Rgeo e_Rp [0/4.1] Error in Rp
123-126 I4 K Teq [157/1403] Planet equilibrium temperature (4)
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Note (1): From Borucki et al. 2011, Cat. J/ApJ/736/19.
Note (2): This work's K-Band stellar measurements. Metallicity measurements
for stars earlier than M0 (Teff>4000K) represent an extrapolation of
the Rojas et al (2012, Cat. J/ApJ/748/93) M dwarf [M/H] calibration.
Note (3): This work's Dartmouth Stellar Interpolants.
Note (4): This work's new planet parameters. The planetary equilibrium
temperatures were calculated assuming an Earth-like albedo and
re-radiation fraction for each planet-candidate. We do not include
uncertainty estimates for this parameter due to the ambiguity of
those assumptions. There is no model in the Dartmouth isochrones with
the same [M/H] and Teff as KOI 961, so this star is interpolated onto
the 5-Gyr BCAH isochrones. See Muirhead et al. (2012ApJ...747..144M 2012ApJ...747..144M)
for a more detailed analysis of this star.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Dec-2013