J/MNRAS/389/585 Fundamental parameters of M dwarfs (Casagrande+, 2008)
M dwarfs: effective temperatures, radii and metallicities.
Casagrande L., Flynn C., Bessell M.
<Mon. Not. R. Astron. Soc., 389, 585-607 (2008)>
=2008MNRAS.389..585C 2008MNRAS.389..585C
ADC_Keywords: Stars, dwarfs ; Stars, M-type ; Photometry, UBVRI ;
Photometry, infrared ; Effective temperatures
Keywords: stars: abundances - stars: atmospheres -
stars: fundamental parameters - Hertzsprung-Russell (HR) diagram -
stars: low-mass, brown dwarf - infrared: stars
Abstract:
We empirically determine effective temperatures and bolometric
luminosities for a large sample of nearby M dwarfs, for which high
accuracy optical and infrared photometry is available. We introduce a
new technique which exploits the flux ratio in different bands as a
proxy of both effective temperature and metallicity. Our temperature
scale for late-type dwarfs extends well below 3000K (almost to the
brown dwarf limit) and is supported by interferometric angular
diameter measurements above 3000K. Our metallicities are in excellent
agreement (usually within 0.2dex) with recent determinations via
independent techniques. A subsample of cool M dwarfs with metallicity
estimates based on hotter Hipparcos common proper motion companions
indicates our metallicities are also reliable below 3000K, a
temperature range unexplored until now. The high quality of our data
allows us to identify a striking feature in the bolometric luminosity
versus temperature plane, around the transition from K to M dwarfs. We
have compared our sample of stars with theoretical models and conclude
that this transition is due to an increase in the radii of the M
dwarfs, a feature which is not reproduced by theoretical models.
Description:
Our basic sample consists of 343 nearby M dwarfs with high-quality
optical and IR photometry.
We apply an extension of the IRFM we developed for G and K dwarfs
(Casagrande et al., 2006, Cat. J/MNRAS/373/13) to M dwarfs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 100 343 Observable and physical quantities for our
sample stars
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See also:
J/MNRAS/334/20 : UBV(RI)c photometry of HIP red stars (Koen+, 2002)
J/AJ/123/2822 : Photometry of southern NLTT stars (Reid+, 2002)
J/AJ/126/3007 : Spectroscopy of faint red NLTT dwarfs (Reid+, 2003)
J/AJ/128/463 : A preliminary 20pc census from NLTT catalogue (Reid+, 2004)
J/MNRAS/373/13 : Lower main-sequence stars fund. param. (Casagrande+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Star name
16- 19 I4 K Teff Effective temperature
21- 23 I3 K e_Teff rms uncertainty on Teff
25- 29 F5.3 mas theta Angular diameter
31- 35 F5.3 mas e_theta rms uncertainty on theta
37- 42 F6.3 mag mBol Apparent bolometric magnitude (1)
44- 49 F6.3 mag Vmag Johnson V magnitude
51- 55 F5.3 mag B-V ?=- Johnson B-V colour index
57- 61 F5.3 mag U-B ?=- Johnson U-B colour index
63- 67 F5.3 mag V-Rc Johnson-Cousins V-Rc colour index
69- 73 F5.3 mag V-Ic Johnson-Cousins V-Ic colour index
75- 80 F6.3 mag Jmag 2MASS Johnson J magnitude
82- 87 F6.3 mag Hmag 2MASS Johnson H magnitude
89- 94 F6.3 mag Ksmag 2MASS Johnson Ks magnitude
96-100 F5.2 [-] [M/H] ?=- Metallicity (2)
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Note (1): Apparent bolometric magnitudes (mBol) are obtained according to
Section 6, where the absolute bolometric magnitude of the Sun
MBol,sun=4.74.
Note (2): For the stars with HIP number, the metallicities are from the
Bonfils et al. (2005A&A...442..635B 2005A&A...442..635B) calibration, while the remainder
are obtained with the MOITE.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 09-Feb-2009