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A&A 461, 253-259 (2007)
DOI: 10.1051/0004-6361:20065268
Periodic radial velocity variations in RU Lupi
H. C. Stempels1, G. F. Gahm2, and P. P. Petrov31 School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, Scotland, UK
e-mail: Eric.Stempels@st-andrews.ac.uk
2 Stockholm Observatory, AlbaNova University Centre, 106 91 Stockholm, Sweden
3 Crimean Astrophysical Observatory, p/o Nauchny, Crimea 98409, Ukraine
(Received 24 March 2006 / Accepted 15 September 2006)
Abstract
Context.
RU Lup
is a Classical T Tauri star with unusually strong emission
lines, which has been interpreted as manifestations of accretion. Recently,
evidence has accumulated that this star might have a variable radial
velocity.
Aims.We intended to investigate in more detail the possible variability in
radial velocity using a set of 68 high-resolution spectra taken at the VLT
(UVES), the AAT (UCLES) and the CTIO (echelle).
Methods.Using standard cross-correlation techniques, we determined the radial
velocity of RU Lup. We analysed these results with Phase-dispersion
minimization and the Lomb-Scargle periodogram and searched for possible
periodicities in the obtained radial velocities. We also analysed
changes in the absorption line shapes and the photometric variability of RU Lup.
Results.Our analysis indicated that RU Lup exhibits variations in radial
velocity with a periodicity of 3.71 days and an amplitude of 2.17 km s-1. These variations can be explained by the presence of large
spots, or groups of spots, on the surface of RU Lup. We also considered a
low-mass companion and stellar pulsations as alternative sources for these
variations but found these to be unlikely.
Key words: stars: pre-main sequence -- stars: starspots -- stars: individual: RU Lupi -- binaries: close
© ESO 2006