Query : 2011A&A...526A..76T

2011A&A...526A..76T - Astronomy and Astrophysics, volume 526A, 76-76 (2011/2-1)

Constrained fitting of disentangled binary star spectra: application to V615 Persei in the open cluster h Persei.


Abstract (from CDS):

Using the technique of spectral disentangling, it is possible to determine the individual spectra of the components of a multiple star system from composite spectra observed at a range of orbital phases. This method has several advantages: it is unaffected by line blending, does not use template spectra, and returns individual component spectra with very high signal-to-noise ratios. The disentangled spectra of a binary star system are very well suited to spectroscopic analysis but for one problem: the absolute spectral line depths are unknown because this information is not contained in the original spectra (unless there is one taken in eclipse) without making assumptions about the spectral characteristics of the component stars. Here we present a method for obtaining the atmospheric parameters of the component stars by the constrained fitting of synthetic spectra to observed and disentangled spectra. Disentangled spectra are fitted using synthetic spectra and a genetic algorithm in order to determine the effective temperatures, surface gravities and relative light contributions of the two stars in a binary system. The method is demonstrated on synthetic spectra and then applied to the eclipsing binary V615 Per, a member of the young open cluster NGC869 (h Persei). The method works well for disentangled spectra with signal-to-noise ratios of 100 or more. For V615 Per we find a normal He abundance but an Mg abundance, which indicates bulk metallicity, a factor of two lower than typical for nearby OB stars.

Abstract Copyright:

Journal keyword(s): binaries: spectroscopic - stars: abundances - stars: atmospheres - open clusters and associations: individual: h Persei

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 - 2024
1 NGC 869 OpC 02 18 57.8 +57 08 02           ~ 472 0
2 V* V615 Per EB* 02 19 01.6485064968 +57 07 19.013821536   13.401 13.047   12.5110 B5.9V 32 0
3 V* V621 Per EB* 02 22 09.7108878600 +57 07 02.305907292 9.14 9.68 9.4000   7.9369 B1.5I 75 0
4 NGC 884 OpC 02 22 20.2 +57 08 56           ~ 485 0
5 V* V380 Cyg EB* 19 50 37.3267754400 +40 35 59.135141652 4.86 5.613 5.680     B1.1III+B2.5/3V: 291 0

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