2009A&A...496..827O


Query : 2009A&A...496..827O

2009A&A...496..827O - Astronomy and Astrophysics, volume 496, 827-832 (2009/3-4)

2M0415+0154: a new bright, short-period subdwarf B pulsator.

OREIRO R., OSTENSEN R.H., GREEN E.M. and GEIER S.

Abstract (from CDS):

The discovery of stellar oscillations in some subdwarf B stars presents the opportunity of studying the interior structure of these objects, thereby clarifying their possible formation channels. Our ongoing survey attempts to increase the number of pulsating hot subdwarfs to better understand the complexities of the various subgroups within the population of pulsators and to identify targets suitable for seismological analysis. Light curves for a list of potential pulsators were obtained at the Nordic Optical Telescope. The candidates were mainly selected based on similar Teff and logg as known pulsators. A frequency analysis of the light curves was performed to investigate the multiperiodic photometric variability. From the sample we surveyed in 2007, 2M0415+0154 was the only star clearly showing photometric modulations. Follow-up photometry revealed three clear pulsation modes with periods between 143 and 150s. Additional spectroscopic data was taken on 2M0415+0154 to refine its physical parameters. We find Teff=34000±500K, logg=5.80±0.05dex, log(NHe/NH)=-1.60±0.05, which are typical of sdB pulsators in this period range. No evidence of a companion was found. A new short-period sdB star has been discovered, 2M0415+0154. Its physical parameters and oscillation frequencies agree with those of other V361Hya stars. The relative brightness and simple frequency spectrum of this star make it a suitable target for empirical mode identification, essential for a seismological analysis of simple pulsators.

Abstract Copyright:

Journal keyword(s): stars: oscillations - stars: subdwarfs - stars: fundamental parameters - stars: individual: 2M0415+0154

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 PG 0014+068 HS* 00 16 54.2537878176 +07 04 30.043437816   15.3       sdO 70 1
2 GALEX J041550.2+015421 HS* 04 15 50.1643047048 +01 54 20.940589764   13.92 14.06 14.36   sdB 7 0
3 V* UY Sex HS* 10 50 02.8265487864 -00 00 36.879009588 12.063 13.184 13.474 13.606 13.769 sdO9VIIHe6 153 0
4 PG 1219+534 HS* 12 21 29.0914917288 +53 04 36.796062144   12.41       sdB 79 1
5 PG 1325+102 HS* 13 27 48.5600155368 +09 54 51.049107756   13.73 13.98 14.29   sdBO 54 1
6 V* V361 Hya ** 14 05 33.00 -27 01 34.1   15.45 15.26 15.16   sdB+ 112 0
7 PG 1618+563 HS* 16 19 26.9188578888 +56 06 01.009178568       13.93   sdB0VIIHe8 25 1
8 PG 1716+426 HS* 17 18 03.8584522800 +42 34 12.562847292   13.69 13.97     sdB2VIIHe3 103 0
9 V* LS Dra HS* 18 24 52.4115107856 +57 47 23.528193612           sdOB 18 0
10 KPD 1930+2752 HS* 19 32 14.8088063952 +27 58 35.445679608 12.80 13.75 13.82     sdB 150 0
11 CD-40 13747 HS* 20 15 04.7880723672 -40 05 44.110361148 11.91 12.09 11.82     sdO 45 0
12 LS IV -14 116 HS* 20 57 38.8746228912 -14 25 43.991016852 11.63 12.73 13.02 13.28   sdB0.5VIIHe18 70 0

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2022.05.27-08:29:11

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