Geier, S. and Marsh, T. R. and Wang, B. and Dunlap, B. and Barlow, B. N. and Schaffenroth, V. and Chen, X. and Irrgang, A. and Maxted, P. F. L. and Ziegerer, E. and Kupfer, T. and Miszalski, B. and Heber, U. and Han, Z. and Shporer, A. and Telting, J. H. and Gänsicke, B. T. and Østensen, R. H. and O'Toole, S. J. and Napiwotzki, R. (2013) A progenitor binary and an ejected mass donor remnant of faint type Ia supernovae. Astronomy and Astrophysics, 554 . Art. No. A54. ISSN 0004-6361. http://resolver.caltech.edu/CaltechAUTHORS:20130821-090518540
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Type Ia supernovae (SN Ia) are the most important standard candles for measuring the expansion history of the universe. The thermonuclear explosion of a white dwarf can explain their observed properties, but neither the progenitor systems nor any stellar remnants have been conclusively identified. Underluminous SN Ia have been proposed to originate from a so-called double-detonation of a white dwarf. After a critical amount of helium is deposited on the surface through accretion from a close companion, the helium is ignited causing a detonation wave that triggers the explosion of the white dwarf itself. We have discovered both shallow transits and eclipses in the tight binary system CD-30°11223 composed of a carbon/oxygen white dwarf and a hot helium star, allowing us to determine its component masses and fundamental parameters. In the future the system will transfer mass from the helium star to the white dwarf. Modelling this process we find that the detonation in the accreted helium layer is sufficiently strong to trigger the explosion of the core. The helium star will then be ejected at such high velocity that it will escape the Galaxy. The predicted properties of this remnant are an excellent match to the so-called hypervelocity star US 708, a hot, helium-rich star moving at more than 750 km s^-1, sufficient for it to leave the Galaxy. The identification of both progenitor and remnant provides a consistent picture of the formation and evolution of underluminous SNIa.
|Additional Information:||© 2013 ESO. Article published by EDP Sciences. Received 3 March 2013; Accepted 16 April 2013. Published online 04 June 2013. Based on observations obtained at the European Southern Observatory, La Silla for programme 089.D-0265(A). Based on observations with the William Herschel Telescope (WHT) operated by the Isaac Newton Group at the Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias on the island of La Palma, Spain. Based on observations made at the South African Astronomical Observatory (SAAO). Based on observations with the Southern Astrophysical Research (SOAR) telescope operated by the US National Optical Astronomy Observatory (NOAO), the Ministrio da Ciencia e Tecnologia of the Federal Republic of Brazil (MCT), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). We acknowledge the Director of SOAR for making the time for these observations during Technical and Engineering nights on the telescope. A.I. acknowledges support from a research scholarship by the Elite Network of Bavaria. V.S. acknowledges funding by the Deutsches Zentrum für Luft- und Raumfahrt (grant 50 OR 1110) and by the Erika-Giehrl-Stiftung. S.G. and E.Z. are supported by the Deutsche Forschungsgemeinschaft (DFG) through grants HE1356/49-1 and HE1356/45-2, respectively. Finally, we want to thank the anonymous referee for helpful comments and suggestions.|
|Subject Keywords:||binaries: spectroscopic; subdwarfs; supernovae: general|
|Official Citation:||A progenitor binary and an ejected mass donor remnant of faint type Ia supernovae S. Geier, T. R. Marsh, B. Wang, B. Dunlap, B. N. Barlow, V. Schaffenroth, X. Chen, A. Irrgang, P. F. L. Maxted, E. Ziegerer, T. Kupfer, B. Miszalski, U. Heber, Z. Han, A. Shporer, J. H. Telting, B. T. Gänsicke, R. H. Østensen, S. J. O’Toole and R. Napiwotzki A&A 554 A54 (2013) DOI: http://dx.doi.org/10.1051/0004-6361/201321395|
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|Deposited By:||Jason Perez|
|Deposited On:||22 Aug 2013 18:32|
|Last Modified:||21 Oct 2013 23:14|
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