2001PASP..113..937S


Query : 2001PASP..113..937S

2001PASP..113..937S - Publ. Astron. Soc. Pac., 113, 937-943 (2001/August-0)

UITBOC 1574: a very distant helium-poor subdwarf O star.

SEIBERT M., CHAYER P., MEURER G.R., SAFFER R. and NAPIWOTZKI R.

Abstract (from CDS):

We have obtained the optical spectrum (3750-7500 Å) and ultraviolet fluxes at 1521 and 2260 Å for the quasar candidate UITBOC 1574. The optical spectrum shows strong Balmer absorption lines through at least n=9 and the He II line at 4686 Å. We compared the optical spectrum with non-LTE stellar atmosphere models and find Teff=46,900±3,000 K, logg=5.6±0.3, and helium abundance log(He/H)=-2.0±0.4. We classify the object as a hot subdwarf O star (sdO). With its high effective temperature and low helium abundance, UITBOC 1574 may be considered as belonging to the hot end of the subdwarf B population. The location of this object on the theoretical Teff-g diagram suggests that it is most likely in a post-extreme horizontal branch evolutionary stage. However, we cannot exclude the possibility that UITBOC 1574 may be a low-mass helium white dwarf precursor. We estimate a spectroscopic distance of 5.6±1.7 kpc with a height of 2.7±0.8 kpc above the Galactic plane if it is a helium-poor sdO. The heliocentric radial velocity of the star is 89±18 km.s–1.

Abstract Copyright:

Journal keyword(s): quasars: individual (UITBOC 1574ignore{, J0943-1403}) - stars: individual (J094545-1417) - Stars: Subdwarfs - Stars: White Dwarfs

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 - 2022
#notes
1 PG 0057+155 HS* 00 59 56.6673699744 +15 44 13.740284580   12.02 12.32     sdB0.2VIIIpHe8 119 1
2 NGC 2992 Sy2 09 45 42.045 -14 19 34.90 13.54 13.14 12.18 12.6 12.2 ~ 838 3
3 [SPB96] 1574 blu 09 45 45.5270831016 -14 17 10.532878188     17.5     ~ 7 0
4 NGC 2993 EmG 09 45 48.325 -14 22 06.02 12.72 13.11 12.64 13.4 13.0 ~ 171 1
5 PG 1339+052 HS* 13 41 31.4796026016 +04 54 46.775443860   15.91 16.15     sdO 13 0

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2022.10.05-20:23:55

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