Ref: ASTROimport-329

Modelling the asymmetric wind of the luminous blue variable binary MWC 314

Lobel, A. ; Groh, J. H. ; Martayan, C. ; Frémat, Y. ; Torres Dozinel, K. ; Raskin, G. ; Van Winckel, H. ; Prins, S. ; Pessemier, W. ; Waelkens, C. ; Hensberge, H. ; Dumortier, L. ; Jorissen, A. ; Van Eck, S. ; Lehmann, H.

published in Astronomy and Astrophysics, 559, pp. A16 (2013)

Abstract: Aims: We present a spectroscopic analysis of MWC 314, a luminous blue variable (LBV) candidate with an extended bipolar nebula. The detailed spectroscopic variability is investigated to determine if MWC 314 is a massive binary system with a supersonically accelerating wind or a low-mass B[e] star. We compare the spectrum and spectral energy distribution to other LBVs (such as P Cyg) and find very similar physical wind properties, indicating strong kinship. Methods: We combined long-term high-resolution optical spectroscopic monitoring and V-band photometric observations to determine the orbital elements and stellar parameters and to investigate the spectral variability with the orbital phases. We developed an advanced model of the large-scale wind-velocity and wind-density structure with 3-D radiative transfer calculations that fit the orbitally modulated P Cyg profile of He i λ5876, showing outflow velocities above 1000 km s-1. Results: We find that MWC 314 is a massive semi-detached binary system of ≃1.22 AU, observed at an inclination angle of i = 72.8° with an orbital period of 60.8 d and e = 0.23. The primary star is a low-vsini LBV candidate of m1 = 39.6 M⊙ and R1 = 86.8 R⊙. The detailed radiative transfer fits show that the geometry of wind density is asymmetric around the primary star with increased wind density by a factor of 3.3, which leads the orbit of the primary. The variable orientation causes the orbital modulation that is observed in absorption portions of P Cyg wind lines. Wind accretion in the system produces a circumbinary disc. Conclusions: MWC 314 is in a crucial evolutionary phase of close binary systems, when the massive primary star has its H envelope being stripped and is losing mass to a circumbinary disc. MWC 314 is a key system for studying the evolutionary consequences of these effects. Table 1, Figs. 1-4, 9, 10, 14-16, 18-20, 23 are available in electronic form at http://www.aanda.org

DOI: 10.1051/0004-6361/201220421
Links: link

The record appears in these collections:
Royal Observatory of Belgium > Astronomy & Astrophysics
Science Articles > Peer Reviewed Articles

 Record created 2016-07-01, last modified 2016-07-06