212 research outputs found
The Metallicity of the HD 98800 System
Pre-main sequence (PMS) binaries and multiples enable critical tests of
stellar models if masses, metallicities, and luminosities of the component
stars are known. We have analyzed high-resolution, high signal-to-noise echelle
spectra of the quadruple-star system HD 98800 and using spectrum synthesis,
computed fits to the composite spectrum for a full range of plausible stellar
parameters for the components. We consistently find that sub-solar metallicity
yields fits with lower values, with an overall best-fit of . This metallicity appears to be consistent with PMS evolutionary
tracks for the measured masses and luminosities of the components of HD 98800
but additional constraints on the system and modelling are needed.Comment: 6 pages, 3 figures, 5 tables. Online-only material: color figure.
Accepted in Ap
A Gas Giant Circumbinary Planet Transiting the F Star Primary of the Eclipsing Binary Star KIC 4862625 and the Independent Discovery and Characterization of the two transiting planets in the Kepler-47 System
We report the discovery of a transiting, gas giant circumbinary planet
orbiting the eclipsing binary KIC 4862625 and describe our independent
discovery of the two transiting planets orbiting Kepler-47 (Orosz et al. 2012).
We describe a simple and semi-automated procedure for identifying individual
transits in light curves and present our follow-up measurements of the two
circumbinary systems. For the KIC 4862625 system, the 0.52+/-0.018 RJup radius
planet revolves every ~138 days and occults the 1.47+/-0.08 MSun, 1.7 +/-0.06
RSun F8 IV primary star producing aperiodic transits of variable durations
commensurate with the configuration of the eclipsing binary star. Our best-fit
model indicates the orbit has a semi-major axis of 0.64 AU and is slightly
eccentric, e=0.1. For the Kepler-47 system, we confirm the results of Orosz et
al. (2012). Modulations in the radial velocity of KIC 4862625A are measured
both spectroscopically and photometrically, i.e. via Doppler boosting, and
produce similar results.Comment: 40 pages, 17 figure
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