Issue |
A&A
Volume 386, Number 3, May II 2002
|
|
---|---|---|
Page(s) | 964 - 970 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20020357 | |
Published online | 15 May 2002 |
Mode characterisation in δ Scuti stars*
I. ρ Pup, GN And, V1208 Aql and AV Cet
1
Institute for Physics and Astronomy, University of Aarhus, Universitetsparken, Bygn. 520, 8000 Aarhus C, Denmark
2
Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain
Corresponding author: T. H. Dall, tdall@ifa.au.dk
Received:
1
May
2001
Accepted:
5
March
2002
We present new spectroscopic observations of four bright δ Scuti
pulsators. Line indices of the Balmer lines can be used to establish mode identifications
using the ratio R between such line index amplitudes and photometric amplitudes.
For the well known radial pulsator ρ Pup an absolute value of the amplitude ratio of the radial mode was found to , consistent with earlier values of
reported for other δ Scuti stars. In GN And we recover the recently reported newly
excited mode, while the former dominant mode was not recovered. We confirm that V1208 Aql
is a non-radial pulsator, containing two modes of different degree. In V1208 Aql we report
a previously unseen mode behavior: the phases of both modes are reversed between the core
and wings of the Hβ line, suggesting the presence of more undetected modes. For
AV Cet we find that the dominant mode is a previously undetected one.
We suggest the undertaking of new photometric observations of ρ Pup, GN And, V1208 Aql and AV Cet
to determine the frequencies and amplitudes of the pulsations.
Key words: stars: oscillations / stars: variables: δ Sct / stars: individual: GN And / stars: individual: V1208 Aql / stars: individual: AV Cet / stars: individual: ρ Pup
© ESO, 2002
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