2009A&A...496..469L


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.12CET00:33:05

2009A&A...496..469L - Astronomy and Astrophysics, volume 496, 469-473 (2009/3-3)

The planet-hosting subdwarf B star V391 Pegasi is a hybrid pulsator.

LUTZ R., SCHUH S., SILVOTTI R., BERNABEI S., DREIZLER S., STAHN T. and HUEGELMEYER S.D.

Abstract (from CDS):

A noticeable fraction of subdwarf B stars shows either short-period (p-mode) or long-period (g-mode) luminosity variations, with two objects so far known to exhibit hybrid behaviour, i.e. showing both types of modes at the same time. The pulsating subdwarf B star V391 Pegasi (or HS2201+2610), which is close to the two known hybrid pulsators in the logg-Teff plane, has recently been discovered to host a planetary companion. In order to learn more about the planetary companion and its possible influence on the evolution of its host star (subdwarf B star formation is still not well understood), an accurate characterisation of the host star is required. As part of an ongoing effort to significantly improve the asteroseismic characterisation of the host star, we investigate the low-frequency behaviour of HS2201+2610. We obtained rapid high signal-to-noise photometric CCD (B-filter) and PMT (clear-filter) data at 2m-class telescopes and carried out a careful frequency analysis of the light curves. In addition to the previously known short-period luminosity variations in the range 342s-367s, we find a long-period variation with a period of 54mn and an amplitude of 0.15 percent. This can most plausibly be identified with a g-mode pulsation, so that HS2201+2610 is a new addition to the short list of hybrid sdB pulsators. Along with the previously known pulsating subdwarf B stars HS0702+6043 and Balloon090100001 showing hybrid behaviour, the new hybrid HS2201+2610 is the third member of this class. This important property of HS2201+2610 can lead to a better characterisation of this planet-hosting star, helping the characterisation of its planetary companion as well. Current pulsation models cannot yet reproduce hybrid sdBV stars particularly well and improved pulsation models for this object have to include the hybrid behaviour.

Abstract Copyright:

Journal keyword(s): subdwarfs - stars: horizontal-branch - stars: oscillations - stars: individual: HS2201+2610

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 V* DW Lyn HS* 07 07 09.7959993247 +60 38 50.158351555   14.7   15.34   sdB 46 1
2 V* V361 Hya ** 14 05 33.00 -27 01 34.1   15.45 15.26 15.16   sdB+ 108 0
3 PG 1716+426 HS* 17 18 03.8584285848 +42 34 12.566188858   13.69 13.97     sdB2VIIHe3 97 0
4 V* V391 Peg HS* 22 04 12.1044101613 +26 25 07.820507559   14.41 14.61 15.00   sdB 99 2
5 Balloon 90100001 HS* 23 15 21.4810383697 +29 05 01.429272894   11.90 12.30     sdB 73 0

    Equat.    Gal    SGal    Ecl

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2019.11.12-00:33:05

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