The discovery of 13 s X-ray pulsations from the hydrogen depleted subdwarf O6 star binary HD49798

被引:0
|
作者
Israel, GL
Stella, L
Angelini, L
White, NE
Kallman, TR
Giommi, P
Treves, A
机构
[1] Scuola Int Super Studi Avanzati, Int Sch Adv Studies, ISAS, I-34014 Trieste, Italy
[2] Osservatorio Astron Roma, I-00040 Monte Porzio Catone, Italy
[3] NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA
[4] ASI, SAX, Sci Data Ctr, I-00198 Rome, Italy
来源
X-RAY TIMING AND COSMIC GAMMA RAY BURSTS | 1998年 / 22卷 / 07期
关键词
D O I
10.1016/S0273-1177(98)00139-2
中图分类号
V [航空、航天];
学科分类号
08 ; 0825 ;
摘要
We discovered strong 13 s pulsations in the X-ray Aux of HD49798 (Israel et al. 1995), a 1.55 d single-component spectroscopic binary containing a hydrogen depleted subdwarf O6 star. The source X-ray spectrum is extremely soft, corresponding to an unabsorbed 0.1-2 keV luminosity of a few x 10(32) erg s(-1) (distance of 650 pc). A higher luminosity might be hidden in the EUV. Our results imply that the unseen companion is an accreting degenerate star, either a white dwarf or a neutron star. In either case HD49798 corresponds to a previously unobserved evolutionary stage of a massive binary system, after common envelope and spiral-in. (C) 1998 COSPAR. Published by Elsevier Science Ltd.
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页码:1035 / 1038
页数:4
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