2004A&A...422.1053O


Query : 2004A&A...422.1053O

2004A&A...422.1053O - Astronomy and Astrophysics, volume 422, 1053-1058 (2004/8-2)

Detection of a companion to the pulsating sdB Feige 48.

O'TOOLE S.J., HEBER U. and BENJAMIN R.A.

Abstract (from CDS):

We present the discovery of a binary companion to the pulsating sdB Feige 48. Using HST/STIS and archival FUSE spectra, we measure a period of 0.376±0.003d and a velocity semi-amplitude of 28.0±0.2km/s. This implies that the companion star must either be of very low mass, or the orbit is at low inclination. Combining 2MASS fluxes, the lack of a reflection effect, results from asteroseismology and a measurement of the rotation velocity of Feige 48, we show that the orbital inclination must be ≤11.4° and that the unseen companion is a white dwarf with mass ≥0.46M. The implications of this discovery, and of binarity amongst sdB pulsators, is then discussed in the context of recent theoretical work on sdB formation. In particular we suggest that radial velocity studies focus on sdB pulsators with no known companion, and that asteroseismological studies of sdBs investigate a larger mass range than previously considered in order to test formation models.

Abstract Copyright:

Journal keyword(s): stars: individual: Feige 48 - stars: binaries: close - stars: oscillations

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* EO Cet HS* 01 23 43.2472884132 -05 05 45.831031643   12.21 12.65     sdOV+F4V 58 0
2 CD-24 731 HS* 01 43 48.5446090530 -24 05 10.224853422   11.6 11.9     sdBHe0 58 0
3 V* UX Sex HS* 10 25 17.3364361944 -09 20 40.566355783   15.89       sdB+ 27 0
4 Feige 48 HS* 11 47 14.4977747924 +61 15 31.790488292   13.12 13.28     sdB 112 0
5 PG 1219+534 HS* 12 21 29.0915970330 +53 04 36.796970097   12.41       sdB 79 1
6 BD+25 2534 HS* 12 37 23.5157891619 +25 03 59.871049394 9.117 10.26 10.59 10.642 10.809 sdB1(k) 217 0
7 V* NY Vir HS* 13 38 48.1466489725 -02 01 49.209465866   13.43 13.66 13.75   sdB1VIIHe1 199 1
8 V* V361 Hya ** 14 05 33.00 -27 01 34.1   15.45 15.26 15.16   sdB+ 110 0
9 PG 1605+072 HS* 16 08 03.6872880396 +07 04 28.747599362   12.53 12.83 13.18   sdB0.2VIHe3 123 0
10 PG 1716+426 HS* 17 18 03.8584285848 +42 34 12.566188858   13.69 13.97     sdB2VIIHe3 99 0
11 KPD 1930+2752 HS* 19 32 14.8086352823 +27 58 35.444970697 12.80 13.75 13.82     sdB 146 0
12 CD-40 13747 HS* 20 15 04.7874862110 -40 05 44.113745580 11.91 12.09 11.82     sdO 44 0
13 HS 2333+3927 HS* 23 35 42.5026291966 +39 44 27.064897144     14.53     sdOB 38 0

    Equat.    Gal    SGal    Ecl

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2021.07.25-21:56:32

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