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J/ApJ/490/328         "Mass Discrepancy" for Massive Stars (Burkholder+ 1997)

The "mass discrepancy" for massive stars: tests of models using spectroscopic binaries Burkholder V., Massey P., Morrell N. <Astrophys. J. 490, 328 (1997)> =1997ApJ...490..328B
ADC_Keywords: Binaries, spectroscopic ; Radial velocities Keywords: binaries: spectroscopic - stars: early-type - stars: evolution - stars: fundamental parameters Abstract: Stellar evolutionary models are often used to infer a star's mass via its luminosity, but empirical checks on the accuracy of the theoretical mass-luminosity relation for very massive stars have been lacking. This is of particular concern given that modern atmosphere models yield systematically smaller masses for massive stars than do evolutionary models, with the discrepancy a factor of two for Of stars. We attempt to resolve this mass discrepancy by obtaining new, high-resolution optical data on seven early-type spectroscopic binaries: V453 Cyg, HD 191201, V382 Cyg, Y Cyg, HD 206267, DH Cep, and AH Cep. Our study produces improved spectral subtypes for the components of these systems, crucial for evaluating their luminosities and locations in the H-R diagram. Our radial velocity study utilizes a measuring method which explicitly accounts for the effects of pair-blending. We combine our new orbit solutions with existing data on inclinations and distances when available to compare the orbital masses with evolutionary models, and we find good agreement in all cases where the stars are non-interacting. (The components of V382 Cyg and DH Cep fill their Roche lobes, and in both cases we find masses substantially lower than the masses inferred from evolutionary tracks, suggesting that significant material has been lost rather than transferred. We confirm that this same trend exists for other systems drawn from the literature.) Our own data extends to only 15 M, although photometric inclination determinations for HD 191201 and HD 206267 should prove possible, and will provide examples of higher mass systems. We briefly discuss suitable systems from the literature, and conclude that orbit solutions provide good agreement with the evolutionary models to 25 M. Beyond this, most known binaries either fill their Roche lobes or have other complications. We also discuss five systems for which our improved data and analysis failed to yield acceptable orbit solutions: EO Aur, IU Aur, V640 Mon (Plaskett's star), LY Aur, and 29 UW CMa all remained intractable, despite improved data. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 22 47 53.0 +65 03 44 AH Cep = HD 216014 22 46 54.1 +58 05 03 DH Cep = HD 215835 20 07 23.7 +35 43 06 HD 191201 21 38 57.5 +57 29 21 HD 206267 20 18 47.2 +36 20 27 V382 Cyg = HD 228854 20 06 34.9 +35 44 27 V453 Cyg = HD 227696 20 52 03.5 +34 39 29 Y Cyg = HD 198846 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 56 143 Radial velocities
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 9 A9 --- ID Star identification 11- 21 F11.3 d HJD Heliocentric Julian Date 23- 26 F4.2 --- Phase Orbital phase 28- 31 I4 km/s RVp Radial velocity of the primary, RV(p) 33- 37 F5.1 km/s O-Cp Obs. RV(p) minus calculated orbital velocity 39- 41 F3.1 --- WTp *Weight given RV(p) in computing orbit 43- 46 I4 km/s RVs Radial velocity of the secondary, RV(s) 48- 52 F5.1 km/s O-Cs Obs. RV(s) minus calculated orbital velocity 54- 56 F3.1 --- WTs *Weight given RV(s) in computing orbit
Note on WTp, WTs: The weight given the primary's, or secondary's, radial velocity in computing the orbit, usually sqrt(number of lines measured).
Origin: AAS CD-ROM series, Volume 9, 1997 Lee E. Brotzman [ADS] 27-Jul-97
(End) [CDS] 05-Feb-1998
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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