J/A+A/430/223 Parameters of cool companions of sdB stars (Lisker+, 2005)
Hot subdwarfs from the ESO Supernova Ia Progenitor Survey.
I. Atmospheric parameters and cool companions of sdB stars.
Lisker T., Heber U., Napiwotzki R., Christlieb N., Han Z., Homeier D.,
Reimers D.
<Astron. Astrophys., 430, 223-243 (2005)>
=2005A&A...430..223L 2005A&A...430..223L
ADC_Keywords: Binaries, spectroscopic ; Stars, subdwarf ; Stars, atmospheres
Keywords: binaries: spectroscopic - stars: abundances - stars: atmospheres -
stars: fundamental parameters - stars: horizontal-branch - subdwarfs
Abstract:
We present the analysis of a high-resolution, high-quality sample of
optical spectra for 76 subdwarf B (sdB) stars from the ESO Supernova
Ia Progenitor Survey (SPY, Napiwotzki et al., 2001A&A...367..973N 2001A&A...367..973N).
Effective temperature, surface gravity, and photospheric helium
abundance are determined simultaneously by fitting the profiles of
hydrogen and helium lines using synthetic spectra calculated from LTE
and NLTE model atmospheres. We perform a detailed comparison of our
measurements with theoretical calculations, both for single star
evolution and for binary population synthesis models of close binary
evolution.
Description:
Observations were obtained at the ESO Very Large Telescope with UT2
(Kueyen) equipped with the UV-Visual Echelle Spectrograph.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 98 76 Results of our spectral analysis.
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See also:
J/A+A/442/1023 : 17 bright subdwarf B stars radial velocity (Edelmann+, 2005)
J/ApJ/613/200 : Hubble Higher z Supernova Search, HHZSS (Strolger+, 2004)
III/235 : Spectroscopically Identified White Dwarfs (McCook+, 2003)
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 Object name
16 A1 --- n_Name [M] M: sdB stars misclassified in the McCook &
Sion (1999, Cat. III/235) catalog of
white dwarfs
18- 22 I5 K Teff ? Effective temperature (1)
23 A1 --- n_Teff [a] a: given value is an upper limit due to the
presence of a cool companion.
25- 28 F4.2 [cm/s2] logg ? Surface gravity (1)
29 A1 --- n_logg [b] b: given value is a lower limit due to the
presence of a cool companion.
31- 32 A2 --- l_logY [≤] Limit flag on logY (1)
33- 37 F5.2 --- logY ? Helium abundance log(N(He)/N(H))
38 A1 --- n_logY [b] b: given value is a lower limit due to the
presence of a cool companion.
40- 44 F5.2 --- logLedd ? Luminosity in Eddington luminosity units
46- 49 F4.2 [solLum] logL ? Luminosity in solar luminosity units (2)
51- 54 F4.2 mag VMAG ? Absolute V magnitude
56- 58 F3.1 kpc Dist ? Distance
60- 61 I2 h RAh Right ascension (J2000)
63- 64 I2 min RAm Right ascension (J2000)
66- 70 F5.2 s RAs Right ascension (J2000)
72 A1 --- DE- Declination sign (J2000)
73- 74 I2 deg DEd Declination (J2000)
76- 77 I2 arcmin DEm Declination (J2000)
79- 82 F4.1 arcsec DEs Declination (J2000)
84- 88 F5.2 mag Bmag Apparent B, V or y magnitude
89 A1 --- n_Bmag [Vy] V: Johnson V magnitude or
y: Stroemgren y magnitude in Bmag
91- 98 A8 --- Notes Notes (3)
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Note (1): Teff, logg and logY are mean values from two or more exposures,
if possible.
Note (2): Luminosity in units of solar luminosity is calculated by assuming
MsdB=0.5
Note (3): Notes as follows:
1 = stars for which there was only one useful exposure.
2 = a cool companion shows Mg I in the spectrum, and possibly
additional features.
3 = the presence of a companion was deduced solely from a flux
contribution at Hα. Atmospheric parameters have been
determined from Balmer and helium lines in the blue part of the
spectrum. Unlike for the stars with earlier type companions,
the contribution of the companion in this spectral region is
irrelevant, and the parameters can be regarded as reliable
(for details see Sect. 5.1).
4 = single-lined objects showing peculiar Hα profiles.
5 = independently classified as sdB by Altmann et al.,
2004A&A...414..181A 2004A&A...414..181A.
6 = central star of the planetary nebula PN G 125.9-47.0
7 = central star of the planetary nebula PN G 211.9+22.6
8 = also in the Palomar-Green survey (PG, Green et al.,
1996, Cat. II/207)
9 = also in the Edinburgh-Cape survey (EC, Stobie et al., 1987, in
Second Conference on Faint Blue Stars IAU Coll., 95, 493)
10 = also in the Montreal-Cambridge-Tololo survey (MCT, Demers et al.,
1987, in Second Conference on Faint Blue Stars IAU Coll., 95, 497)
11 = In Table 1 of alt04, V magnitudes of this star and HE 2156-1732
have to be interchanged (M. Altmann, priv. comm.).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Jun-2006