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
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). 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:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 98 76 Results of our spectral analysis.
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
Bytes Format Units Label Explanations
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)
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. 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.).
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Jun-2006
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