V505 Mon -An early-type binary with a disk

Abstract

Abstract. New spectra of the eclipsing binary V505 Mon (usually classified as B5 Ib) were obtained in the optical and UV regions. Only spectral lines of one component are visible, with K = 93 km s −1 . According to arguments based on the extent of the disk the mass ratio might be about 0.30. The star with the visible spectral lines would then have a mass of 2.3, the other component of 7.7 M , i.e. their supergiant nature can be ruled out. The distance to the system appears to be about 1 kpc. Together with published photometric data, the spectroscopy provides clear evidence for the presence of a disk around the secondary component. The profiles of the C ii 1335/6 doublet lines are used to derive the rotational velocity of the disk. The structure of the disk can be characterized by a central ionized zone surrounded by neutral outer parts. Additional matter of cloudy nature has to be present, and both components are embedded in an extended atmosphere. Abundance of carbon was found to be very low. Similarity with some other non-eclipsing binaries is discussed.

Investigation of Times of Minima of Selected Early-Type Eclipsing Binaries

“…SZ Cam. The new time of minimum fits well to the forecast of the O − C curve published by Mayer et al (1994); also minima published by Gorda (2000) fit the forecast. The solid curve represents the effect of the third-body in a highly eccentric orbit (e 0.77) with a period of 50.7 years and an amplitude of 0.086 days (Lorenz et al, 1998).…”

The Multiple System SZ Cam

“…It is composed of four stars: an SB2 eclipsing binary, which is physically bound to an SB1 binary pair. The multiple nature of SZ Cam has been studied by many authors (Mayer et al 1994;Lorenz et al 1998;Harries et al 1998;Gorda 2002). We present the results obtained from the spectroscopic analysis of the system.…”

Binaries with Invisible Massive Components

“…An eclipse can be present, however the light curve can be explained as ellipsoidal, due to a component close to its Roche lobe. Sahade et al 1992Mayer et al 2001Thackeray 1971Hutchings, Redman 1973Hill et al 1976Bolton, Hurkens 2001 In the cases that the Hipparcos parallax is meaningful, one gets the following absolute visual magnitudes: -2.25 (V742 Cas; B5 II), -3.38 (FY Vel; B2 la) and -2.18 (V1362; B5 II) -always considerably fainter than the supergiant classification would suggest. Anyway "luminosity uncertain" might be also considered as characteristic.…”