Query : 2014A&A...570A...3S

2014A&A...570A...3S - Astronomy and Astrophysics, volume 570A, 3-3 (2014/10-1)

HD 50975: a yellow supergiant in a spectroscopic binary system.


Abstract (from CDS):

Recent detection of a yellow supergiant star as a possible progenitor of a supernova has posed serious questions about our understanding of the evolution of massive stars. The spectroscopic binary star HD50975 with an unseen hot secondary was studied in detail with the main goal of estimating fundamental parameters of both components and the binary system. A comprehensive analysis and modeling of collected long-term radial velocity measurements, photometric data, and spectra was performed to calculate orbital elements, atmospheric parameters, abundances, and luminosities. The spectrum in an ultraviolet region was studied to clarify the nature of an unseen companion star. The orbital period was found to be 190.22±0.01-days. The primary star (hereafter HD50975A) is a yellow supergiant with an effective temperature Teff=5900 ±150K and a surface gravity of log(g)=1.4±0.3(cgs). The atmosphere of HD50975 A is slightly metal deficient relative to solar, [Fe/H]=-0.26±0.06dex. Abundances of Si and Ca are close to the scaled solar composition. The r-process element europium is enhanced, [Eu/H]=+0.61±0.07. The bolometric magnitude of the primary was estimated to be Mbol=-5.5±0.3mag and its mass to be 10.7±2.0M. The secondary (hereafter HD50975B) is a hot star of spectral type ∼B2 near ZAMS with an effective temperature of Teff≃21000K and a mass M≃8.6M. The distance between HD50975A and B is about 370R. The binary star is near a semi-detached configuration with a radius, RA≃107R, and a radius of Roche lobe of about 120R for the primary star.

Abstract Copyright:

Journal keyword(s): binaries: spectroscopic - stars: evolution - stars: fundamental parameters - stars: individual: HD 50975 - stars: abundances

VizieR on-line data: <Available at CDS (J/A+A/570/A3): spectrum.dat>

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 HD 50975 SB* 06 55 48.2323725480 +08 52 38.758933812   8.19 7.52     F8Ib: 30 0
2 SN 2008ax SN* 12 30 40.80 +41 38 16.1   23.6 23.5 14.1 22.6 SNIIb 245 1
3 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 4189 4
4 SN 2011dh SN* 13 30 05.10555 +47 10 10.9227           SNIIb 354 1
5 * gam Cyg V* 20 22 13.7018357 +40 15 24.044963 3.44 2.90 2.23 1.74 1.40 F8Ib 576 0

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