The shortest period sdB plus white dwarf binary CD-30 11223 (GALEX J1411-3053)

Vennes, S. and Kawka, A. and O'Toole, S. J. and Nemeth, P. and Burton, D. (2012) The shortest period sdB plus white dwarf binary CD-30 11223 (GALEX J1411-3053). The Astrophysical Journal Letters, 759 (1). L25 (1)-L25 (5). ISSN 2041-8205

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We report on the discovery of the shortest period binary comprising a hot subdwarf star (CD-30 11223, GALEX J1411-3053) and a massive unseen companion. Photometric data from the All Sky Automated Survey show ellipsoidal variations of the hot subdwarf primary and spectroscopic series revealed an orbital period of 70.5minutes. The large velocity amplitude suggests the presence of a massive white dwarf in the system (M 2/M ⊙ ≳ 0.77) assuming a canonical mass for the hot subdwarf (0.48 M ⊙), although a white dwarf mass as low as 0.75 M ⊙ is allowable by postulating a subdwarf mass as low as 0.44 M ⊙. The amplitude of ellipsoidal variations and a high rotation velocity imposed a high-inclination to the system (i ≳ 68°) and, possibly, observable secondary transits (i ≳ 74°). At the lowest permissible inclination and assuming a subdwarf mass of 0.48 M ⊙, the total mass of the system reaches the Chandrasekhar mass limit at 1.35 M ⊙ and would exceed it for a subdwarf mass above 0.48 M ⊙. The system should be considered, like its sibling KPD 1930+2752, a candidate progenitor for a Type Ia supernova. The system should become semi-detached and initiate mass transfer within 30 Myr.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version made accessible, in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 03 Feb 2013 05:05
Last Modified: 12 May 2017 06:02
Uncontrolled Keywords: binaries: close; white dwarfs;
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020106 High Energy Astrophysics; Cosmic Rays
09 Engineering > 0915 Interdisciplinary Engineering > 091505 Heat and Mass Transfer Operations
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1088/2041-8205/759/1/L25

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