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Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars

Muirhead, Philip S. and Hamren, Katherine and Schlawin, Everett and Rojas-Ayala, Bárbara and Covey, Kevin R. and Lloyd, James P. (2012) Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars. Astrophysical Journal Letters, 750 (2). L37. ISSN 2041-8205. doi:10.1088/2041-8205/750/2/L37. https://resolver.caltech.edu/CaltechAUTHORS:20120529-114131163

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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 (T_eff ≲ 4400 K) Kepler Objects of Interest (KOIs) from Borucki et al. We identified one object as a giant (KOI 977); for the remaining dwarfs, we measured effective temperatures (T_eff) and metallicities [M/H] using the K-band spectral indices of Rojas-Ayala et al. 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 T_eff. 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). The stellar parameters presented in this Letter serve as a resource for prioritization of future follow-up efforts to validate and characterize the cool KOI planet candidates.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/2041-8205/750/2/L37DOIArticle
http://iopscience.iop.org/2041-8205/750/2/L37PublisherArticle
ORCID:
AuthorORCID
Muirhead, Philip S.0000-0002-0638-8822
Covey, Kevin R.0000-0001-6914-7797
Additional Information:© 2012 American Astronomical Society. Received 2011 September 4; accepted 2012 April 5; published 2012 April 23. We thank Michael Cushing for providing us with a version of the Spextool package for the TripleSpec Spectrograph at Palomar. We also thank John Johnson for his thoughtful comments on the Letter. The Palomar 200 inch Telescope time was provided by Cornell University. K.R.C. acknowledges support for this work from the Hubble Fellowship Program, provided by NASA through Hubble Fellowship grant HST-HF-51253.01-A awarded by the STScI, which is operated by the AURA, Inc., for NASA, under contract NAS 5-26555.
Funders:
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF-51253.01-A
NASANAS 5-26555
Subject Keywords:planetary systems; stars: abundances; stars: fundamental parameters; stars: late-type; stars: low-mass
Issue or Number:2
DOI:10.1088/2041-8205/750/2/L37
Record Number:CaltechAUTHORS:20120529-114131163
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120529-114131163
Official Citation:Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars Philip S. Muirhead et al. 2012 ApJ 750 L37
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31679
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:29 May 2012 20:42
Last Modified:09 Nov 2021 19:58

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