lAU-Symposium No. 90, (1985) on Crimea (USSR) on Upper Main Sequence Stars with Anomalous Abundances,
eds. C.R. Cowley et al., Reidel Publ. Company 1986, p. 235-238

Short-Periodic Radial Velocity Variations
of the B9p Star ET And

E. Gerth

Academy of Sciences of the GDR, Central Institute of Astrophysics, Potsdam (GDR)
Zentralinstitut für Astrophysik der Akademie der Wissenschaften der DDR, DDR-1500 Potsdam Telegrafenberg

Spectroscopic observations of the B9p star ET And secured at the Bulgarien national Observatory Roshen in the years 1981-1984, consisting of 97 plates, show clearly a radial velocity period of 0,198 d - with a ratio to the photometrical period of exactly 2 : 1. This behaviour would hint at a close binary system; but there arise difficulties in explaining it by this way because of the extreme short period, so that pulsation must be taken into account. However, besides of the confident period of 0.198 d, there is evidence for shorter periods in the region of 45 min, which may be attributed only to pulsational processes.

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