Toward Understanding the B[e] Phenomenon. VII. AS 386, a single-lined binary with a candidate black hole component

Abstract

We report the results of spectroscopic and photometric observations of the emission-line object AS 386. For the first time, we found that it exhibits the B[e] phenomenon and fits the definition of an FS CMa type object. The optical spectrum shows the presence of a B-type star with the following properties: T_ eff = 11000+/-500 K, log L/L_sun = 3.7+/-0.3, a mass of 7+/-1 M_sun, and a distance D = 2.4+/-0.3 kpc from the Sun. We detected regular radial velocity variations of both absorption and emission lines with the following orbital parameters: P_orb = 131.27+/-0.09 days, semi-amplitude K_1 = 51.7+/-3.0 km/s, systemic radial velocity gamma = -31.8+/-2.6 km/s, and a mass function of f(m) = 1.9+/-0.3 M_sun. AS 386 exhibits irregular variations of the optical brightness (V=10.92+/-0.05 mag), while the near-IR brightness varies up to ~0.3 mag following the spectroscopic period. We explain this behavior by a variable illumination of the dusty disk inner rim by the B-type component. Doppler tomography based on the orbital variations of emission-line profiles shows that the material is distributed near the B-type component and in a circumbinary disk. We conclude that the system has undergone a strong mass transfer that created the circumstellar material and increased the B-type component mass. The absence of any traces of a secondary component, whose mass should be >= 7 M_sun, suggests that it is most likely a black hole.

arXiv comment18 pages, 4 tables, 13 figures, Accepted for publication in ApJ

References in corpus (16)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
• Passive irradiated circumstellar disks with an inner hole
• The AKARI/IRC Mid-Infrared All-Sky Survey
• Northern Sky Variability Survey (NSVS): Public data release
• Formation of contact in massive close binaries
• Bright OB stars in the Galaxy IV. Stellar and wind parameters of early to late B supergiants
• Dust Emission from Herbig Ae/Be stars - Evidence for Disks and Envelopes
• Near infrared and the inner regions of protoplanetary disks
• Spectroscopic survey of emission-line stars. I. B[e] stars
• Tycho 2 stars with infrared excess in the MSX Point Source Catalogue
• Hydrogen in hot subdwarfs formed by double helium white dwarf mergers
• On the formation and evolution of the first Be star in a black hole binary MWC 656
• AMBER/VLTI observations of the B[e] star MWC 300
• Toward Understanding The B[e] Phenomenon: V. Nature and Spectral Variations of the MWC 728 Binary System

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