Issue |
A&A
Volume 383, Number 1, FebruaryIII 2002
|
|
---|---|---|
Page(s) | 239 - 243 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20011712 | |
Published online | 15 February 2002 |
PG 1325+101 and PG 2303+019: Two new large amplitude subdwarf B pulsators*
1
Osservatorio Astronomico di Capodimonte, via Moiariello 16, 80131 Napoli, Italy
2
Isaac Newton Group of Telescopes, 37800 Santa Cruz de La Palma, Canary Islands, Spain e-mail: roy@ing.iac.es
3
Institutt for Fysikk, Universitetet i Tromsø, 9037 Tromsø, Norway e-mail: jan-erik.solheim@phys.uit.no
4
Dr. Remeis-Sternwarte, Astronomisches Institut der Universität Erlangen-Nürnberg, 96049 Bamberg, Germany e-mail: ai03@sternwarte.uni-erlangen.de
5
Institut für Astronomie und Astrophysik, Sand 1, 72076 Tübingen, Germany e-mail: dreizler@astro.uni-tuebingen.de
6
Sternwarte der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany e-mail: maltmann@astro.uni-bonn.de
Corresponding author: R. Silvotti, silvotti@na.astro.it
Received:
6
November
2001
Accepted:
3
December
2001
We report the detection of short period oscillations in the sdB stars
PG 1325+101 () and PG 2303+019 (alias HS 2303+0152,
) from
time-series photometry made at the Nordic Optical Telescope
of a sample of 21 candidates.
Both stars are multi-mode pulsators with at least three distinct periods
in the range 100–140 s, and relatively large amplitudes up to 2.6 and
1.6% respectively.
Moreover PG 1325+101 shows the shortest pulsation period ever registered
among sdBV stars, 68.9 s, which corresponds to the first harmonic of the
main signal.
Following previous temperature and gravity determinations for PG 1325+101
(Teff = 34 500 K,
) and our NLTE model atmosphere analysis for
PG 2303+019 (Teff = 35 200 K,
), both stars are well inside the
theoretical sdBV instability strip.
Key words: stars: subdwarfs / stars: oscillations / stars: individual: PG 1325+101, PG 2303+019
Based on observations obtained at the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias; and at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Plank-Institute für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy.
© ESO, 2002
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