The line-profile variable Scorpii is a spectroscopic triple system *
K. De Mey 1,
C. Aerts 1,
C. Waelkens 1,
S.R. Cranmer 2,
C. Schrijvers 3,
J.H. Telting 4,
K. Daems 1,
G. Meeus 1
Received 3 January 1997 / Accepted 4 March 1997
An analysis of 278 spectra of the line-profile variable Scorpii leads to the following conclusions.
Sco is the primary of a binary system. The radial-velocity variations have a peak-to-peak amplitude of 60 km/s and an orbital period of 5.959 days. The orbit is not circular but has an eccentricity of 0.29. The .959-binary system probably moves in orbit with another distant, as yet unknown third star.
By means of three five-hour time series of high-resolution spectra, the oscillations of the rapidly rotating Cephei-type main component are investigated. Line-profile variations, which reveal travelling subfeatures across the lines, are discovered. Sco is so far one of the very few Cephei stars in which such a moving-bump phenomenon is detected. Radial-velocity variations are derived from the data and analysed to reveal a main oscillation frequency near 4.66 cycles day-1, and some more candidate frequencies. Sco is a non-radially pulsating Cephei star which rotates supersynchronously.
The characteristics of Sco and the Oph stars are briefly addressed. Despite the common line-profile behaviour, spectral type, and , we find no evidence of circumstellar material around Sco.
Key words: stars: binaries: spectroscopic stars: oscillations stars: individual: Scorpii line: profiles
* Based on observations collected at the European Southern Observatory, La Silla, Chile.
© European Southern Observatory (ESO) 1997
Online publication: May 5, 1998