Chemical History of Algol and its Components

Abstract

Abstract. We present a new observational project to study the hierarchical triple stellar system Algol, concentrating on the semidetached eclipsing binary at the heart of the system. Over 140 high-resolution and high-S/N spectra have been secured, of which 80 are from FIES at the Nordic Optical Telescope, La Palma, and the remainder were obtained with BOES at the Bohyunsan Optical Astronomy Observatory in Korea. All three components were successfully detected by the method of spectral disentangling, which yields the individual spectra of the three stars and also high-quality spectroscopic elements for both the inner and outer orbits. We present a detailed abundance study for the mass-accreting component in the inner orbit, which holds information on the history of mass transfer in the close inner binary system. We also reveal the atmospheric parameters and chemical composition of the tertiary component in the outer orbit.

Spectroscopically resolving the Algol triple system

“…Pavlovski et al 2009;Lehmann et al 2013;Tkachenko et al 2014;Borkovits et al 2014), including cases with only ∼2.5% (Torres et al 2014), and 1.5-2% (Holmgren et al 1999;Mayer et al 2013) in the V spectral region. As was shown in our preliminary reports on SPD of Algol (Pavlovski et al 2010;Kolbas et al 2012) we are pushing The rotational distortion of the spectral lines during eclipse (the Rossiter-McLaughlin effect) violates the principal assumption of spectral disentangling that spectral line profiles are not intrinsically variable, so spectra obtained during eclipse cannot be used. Without such spectra there is insufficient variation in the light contributions of the components during the orbit, so the zeroth mode in the Fourier expansion is undetermined.…”

Algol anomaly or careful observations of its brightness? The values recorded for the magnitude of Algol in the medieval astronomical corpus

“…The primary (Algol A) is a B8 V main sequence star with a mass in the range 3.4 M  , the secondary (Algol B) is a K2 IV subgiant with a mass of 0.77 M  , and the tertiary (Algol C) is estimated to be a main sequence star of spectral type F1V and a mass of 1.6 M  . 3 Algol systems present an apparent paradox in that the less massive star of the binary appears to be more evolved than the more massive primary. They have in fact undergone a period of mass transfer 4 during which substantial material was transferred from the initially more massive present-day late-type star to its initially less massive early-type companion.…”