J/ApJ/709/535 Masses and radii of eclipsing binaries (Brown, 2010)
Radii of rapidly rotating stars, with application to transiting-planet hosts.
Brown T.M.
<Astrophys. J., 709, 535-545 (2010)>
=2010ApJ...709..535B 2010ApJ...709..535B
ADC_Keywords: Binaries, eclipsing ; Models ; Planets ; Stars, masses ;
Stars, diameters ; Stars, double and multiple
Keywords: binaries: eclipsing - methods: data analysis -
stars: fundamental parameters - stars: oscillations
Abstract:
The currently favored method for estimating radii and other parameters
of transiting-planet host stars is to match theoretical models to
observations of the stellar mean density ρ*, the effective
temperature Teff, and the composition parameter [Z]. This explicitly
model-dependent approach is based on readily available observations,
and results in small formal errors. Its performance will be central to
the reliability of results from ground-based transit surveys such as
TrES, HAT, and SuperWASP, as well as to the space-borne missions MOST,
CoRoT, and Kepler. Here, I use two calibration samples of stars
(eclipsing binaries (EBs) and stars for which asteroseismic analyses
are available) having well-determined masses and radii to estimate the
accuracy and systematic errors inherent in the ρ* method. When
matching to the Yonsei-Yale stellar evolution models, I find the most
important systematic error results from selection bias favoring
rapidly rotating (hence probably magnetically active) stars among the
EB sample. If unaccounted for, this bias leads to a mass-dependent
underestimate of stellar radii by as much as 4% for stars of
0.4M☉, decreasing to zero for masses above about 1.4M☉.
Relative errors in estimated stellar masses are three times larger
than those in radii.
Description:
I implemented the ρ* method, using the Yonsei-Yale evolution
tracks (Yi et al. 2001ApJS..136..417Y 2001ApJS..136..417Y; Kim et al. 2002ApJS..143..499K 2002ApJS..143..499K;
Yi et al. 2003ApJS..144..259Y 2003ApJS..144..259Y; Demarque et al. 2004ApJS..155..667D 2004ApJS..155..667D) as
the needed stellar evolution models, and I then applied it to the
Torres et al., (2009, Cat. J/other/A+ARV/18.67) tabulation of EBs and
to 15 stars with asteroseismic measurements.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 156 *Eclipsing binary stars with accurate mass and
radius estimates
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Note on table1.dat: Data for masses, radii, Teff and [Z] are from Torres
et al. (2009, Cat. J/other/A+ARV/18.67).
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See also:
V/121 : Catalog of DMS-type eclipsing binaries (Svechnikov+, 1999)
V/118 : Catalog of eclipsing binaries parameters (Perevozkina+, 1999)
J/A+A/526/A99 : Metal-poor solar-type stars spectroscopy and masses
(Sousa+, 2011)
J/A+A/527/A140 : Mass limits on substellar companions (Reffert+, 2011)
J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)
J/ApJ/709/535 : Masses and radii of planet hosts (Brown, 2010)
J/ApJ/694/1085 : Radii of exoplanet host stars (van Belle+, 2009)
http://www.astro.yale.edu/demarque/yystar.html : Y2 (Yonsei-Yale) stellar
models page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Star name (binary name and component)
17- 21 F5.3 Msun Mass Mass of the star
23- 27 F5.3 Msun e_Mass rms on Mass
29- 34 F6.3 Rsun Rad Radius of the star
36- 40 F5.3 Rsun e_Rad rms on Rad
42- 46 I5 K Teff Effective temperature
48- 50 I3 K e_Teff rms on Teff
52- 57 F6.3 [Sun] [Z] ?=0 Logarithmic metal abundance relative to
solar
59- 63 F5.3 [Sun] e_[Z] ?=0.2 rms uncertainty on [Z]
65- 69 F5.3 Msun Mfit Mass estimated by fit (1)
71- 76 F6.3 Rsun Rfit Radius estimated by fit (1)
78- 83 F6.2 Gyr Agefit Age estimated by fit (1)
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Note (1): For each star, I applied the Markov Chain Monte Carlo (MCMC)
procedure with the search over stellar models constrained by the
star's mean density (computed from the Torres et al. 2009, mass and
radius, see Cat. J/other/A+ARV/18.67), Teff, and [Z]. The MCMC/amoeba
procedure then yielded new estimates of the stellar mass, radius,
luminosity, age, mean density, Teff, and [Z], where the procedure
necessarily returned values of the last three quantities that were
much less than 1 standard deviation from those that were provided as
input. The values of M*, R*, and A* derived by this method are
listed in the last three columns (labeled "fit").
See text for further details.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 02-Mar-2012