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Weak lensing by galaxies in groups and clusters – I. Theoretical expectations
Authors:Xiaohu Yang  H J Mo  Frank C van den Bosch  Y P Jing  Simone M Weinmann  M Meneghetti
Institution:The Observatories, Madingley Road, Cambridge CB3 0HA
Abstract:Three of the six southern Clube Areas that were mainly observed at the European Southern Observatory and whose principal results are given in Paper XVI are marginally observable from Haute-Provence. Additional measurements obtained on several observing runs there enabled orbits to be determined (in most cases rather poorly, owing to the paucity of data) for 30 of the newly discovered spectroscopic-binary systems; they are presented in this paper. One object, HD 33978, seems to be of such significance that special efforts have been made, largely by Drs J. Andersen and H. Lindgren, to obtain additional radial-velocity measurements. That system is shown to be a double-lined binary with a period of only 10.67 d despite one of its components being a late-type giant. The giant star has a projected rotational velocity of almost 40 km s−1; it could be expected to exhibit RS CVn-type photometric variations, which have not yet been observed, in addition to the 'ellipsoidal variation', discovered by Hipparcos , which occasioned its designation as VV Lep.
Keywords:techniques: radial velocities  binaries: spectroscopic  stars: individual: HD 33978 (VV Lep)  stars: late-type
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