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


C.D.S. - SIMBAD4 rel 1.7 - 2020.05.29CEST04:05:16

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

Status at CDS:  

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 - 2020
#notes
1 PG 0014+068 HS* 00 16 54.2524890907 +07 04 30.045980038   15.3       sdO 68 1
2 GALEX J041550.2+015421 HS* 04 15 50.1645554667 +01 54 20.937884018   13.92 14.06 14.36   sdB 5 0
3 V* UY Sex HS* 10 50 02.8264873492 -00 00 36.880346331 12.063 13.184 13.474 13.606 13.769 sdO9VIIHe6 149 0
4 PG 1219+534 HS* 12 21 29.0915970330 +53 04 36.796970097   12.41       sdB 78 1
5 PG 1325+102 HS* 13 27 48.5602550889 +09 54 51.048576366   13.73 13.98 14.29   sdBO 52 1
6 V* V361 Hya ** 14 05 33.00 -27 01 34.1   15.45 15.26 15.16   sdB+ 108 0
7 PG 1618+563 HS* 16 19 26.9188451132 +56 06 01.012938189       13.93   sdB0VIIHe8 23 1
8 PG 1716+426 HS* 17 18 03.8584285848 +42 34 12.566188858   13.69 13.97     sdB2VIIHe3 97 0
9 V* LS Dra HS* 18 24 52.4120966396 +57 47 23.542106851           sdOB 16 0
10 KPD 1930+2752 HS* 19 32 14.8086352823 +27 58 35.444970697 12.80 13.75 13.82     sdB 144 0
11 CD-40 13747 HS* 20 15 04.7874862110 -40 05 44.113745580 11.91 12.09 11.82     sdO 42 0
12 LS IV -14 116 HS* 20 57 38.8745387224 -14 25 43.995275738 11.63 12.73 13.02 13.28   sdB0.5VIIHe18 58 0

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2020.05.29-04:05:16

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