2011ApJ...731L..13O


Query : 2011ApJ...731L..13O

2011ApJ...731L..13O - Astrophys. J., 731, L13 (2011/April-2)

GALEX J201337.6+092801: the lowest gravity subdwarf b pulsator.

OSTENSEN R.H., PAPICS P.I., OREIRO R., REED M.D., QUINT A.C., GILKER J.T., HICKS L.L., BARAN A.S., FOX MACHADO L., OTTOSEN T.A. and TELTING J.H.

Abstract (from CDS):

We present the recent discovery of a new subdwarf B variable (sdBV), with an exceptionally low surface gravity. Our spectroscopy places it at Teff= 32,100±1000, log g = 5.15±0.20, and log(NHe/NH) = -2.8 ±0.2. With a magnitude of B = 12.0, it is the second brightest V361 Hya star ever found. Photometry from three different observatories reveals a temporal spectrum with 11 clearly detected periods in the range 376-566 s, and at least five more close to our detection limit. These periods are unusually long for the V361 Hya class of short-period sdBV pulsators, but not unreasonable for p- and g-modes close to the radial fundamental, given its low surface gravity. Of the ∼50 short-period sdB pulsators known to date, only a single one has been found to have comparable spectroscopic parameters to GALEX J201337.6+092801(J20136+0928, for short). This is the enigmatic high-amplitude pulsator V338 Ser, and we conclude that J20136+0928 is the second example of this rare subclass of sdB pulsators located well above the canonical extreme horizontal branch in the H-R diagram.

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Journal keyword(s): stars: early-type - stars: individual: GALEX J201337.6+092801 - stars: variables: general - subdwarfs

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 - 2026
#notes
1 V* DW Lyn HS* 07 07 09.7960158264 +60 38 50.159268348   14.7   15.34   sdB 61 1
2 GALEX J080656.7+152718 HS* 08 06 56.6844688416 +15 27 19.968237288   14.30 14.69 14.72 14.80 sdB 24 0
3 PG 1605+072 HS* 16 08 03.6872637792 +07 04 28.748468964   12.53 12.83 13.18   sdB0.2VIHe3 136 0
4 TYC 1077-402-1 SB* 20 13 33.3323327904 +09 26 26.211518196   12.09 11.73     ~ 2 0
5 GALEX J201337.6+092801 HS* 20 13 37.6121506872 +09 28 01.414212024   12.02 12.23 12.82   sdOB 15 0

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