Issue |
A&A
Volume 408, Number 3, September IV 2003
|
|
---|---|---|
Page(s) | 971 - 979 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20030946 | |
Published online | 17 November 2003 |
High resolution spectroscopy of circumstellar material around A stars*
Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
Corresponding author: M. Hempel, mhempel@hs.uni-hamburg.de
Received:
23
December
2002
Accepted:
13
June
2003
We have analysed a time series of high resolution spectra () of
the Caii K line of 9 stars which are candidates for the presence of
circumstellar material from our previous studies.
We have searched for variable narrow absorption
components similar to those extensively studied in the case of
β Pictoris.
Our data show long-term variations in the spectra of HR 2550 and
HR 3685 which can be attributed to the dynamics of circumstellar
gas. About one third of the sample stars show variable line absorption
but only β Pictoris seems to
exhibit uniquely strong variations on short (nightly) timescales. In order to examine possible interstellar
contributions we compared our results with interstellar data from the
literature. The column densities of our absorption features are
up to three orders of magnitude higher than those found for the
Local Interstellar Cloud.
Key words: stars: circumstellar matter / ISM: atoms / stars: individual: β Pictoris
© ESO, 2003
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