We obtained high-resolution spectra and multicolor photometry of V1082 Sgr to study the donor star in this 20.8 hr orbital period binary, which is assumed to be a detached system. We measured the rotational velocity (v sin i = 26.5+/-2.0 km/s), which, coupled with the constraints on the white dwarf mass from the X-ray spectroscopy, leads to the conclusion that the donor star barely fills 70% of its corresponding Roche lobe radius. It appears to be a slightly evolved K2-type star. This conclusion was further supported by a recently published distance to the binary system measured by the Gaia mission. At the same time, it becomes difficult to explain a very high (> 10e-9 Msun/yr) mass transfer and mass accretion rate in a detached binary via stellar wind and magnetic coupling.
@article{arxiv.1811.08049,
title = {Quest for the Donor Star in the Magnetic Precataclysmic Variable V1082 Sgr},
author = {G. Tovmassian and J. F. Gonzalez and M. -S. Hernandez and D. Gonzalez-Buitrago and S. Zharikov and J. V. Hernandez Santisteban},
journal= {arXiv preprint arXiv:1811.08049},
year = {2018}
}
Comments
16 pages, 10 figures, accepted for publication in Ap.J