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Astron. Astrophys. 339, 150-158 (1998)


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A new bright [FORMULA] Cephei star: line-profile variability in [FORMULA]1 Sco *

John H. Telting 1 and Coen Schrijvers 2

1 Isaac Newton Group of Telescopes, ASTRON/NFRA, Apartado 321, E-38780 Santa Cruz de La Palma, Spain (jht@ing.iac.es)
2 Astronomical Institute Anton Pannekoek, University of Amsterdam and Center for High Energy Astrophysics, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands (coen@astro.uva.nl)

Received 5 March 1998 / Accepted 17 July 1998

Abstract

We present a time series of high-resolution spectra, showing the line-profile variations in the SiIII triplet ([FORMULA] 4552, 4567, 4574 Å) of the rotating early-type star [FORMULA] Sco. The profile variations can be explained by a non-radial pulsation mode.

We analyse the spectral time series by making Fourier transforms for each position in the line profile. Significant power is found only at a frequency of 15.0 cycles/day, suggesting that the profile variations are due to one dominant pulsation mode. From the difference in phase of the variations of the blue and the red wings of the profiles we infer that the star pulsates in a mode with pulsational degree [FORMULA]. From comparison with model calculations we estimate the velocity amplitude of this pulsation to be [FORMULA]10 km/s at the stellar surface.

Key words: line: profiles – stars: early-type – stars: oscillations – stars: rotation – stars: variables: other – stars: individual: !1 Sco

* Based on data taken at ESO La Silla

© European Southern Observatory (ESO) 1998

Online publication: September 30, 1998

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