Three Hypervelocity White Dwarfs in Gaia DR2: Evidence for Dynamically Driven Double-degenerate Double-detonation Type Ia Supernovae
AuthorShen, Ken J.
Gänsicke, Boris T.
Jha, Saurabh W.
Andrews, Jennifer E.
Foley, Ryan J.
Kotze, Marissa M.
Siebert, Matthew R.
Kerzendorf, Wolfgang E.
Townsley, Dean M.
Williams, Brian J.
AffiliationUniv Arizona, Steward Observ
nuclear reactions, nucleosynthesis, abundances
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationKen J. Shen et al 2018 ApJ 865 15
Rights© 2018. The American Astronomical Society. All rights reserved.
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AbstractDouble detonations in double white dwarf (WD) binaries undergoing unstable mass transfer have emerged in recent years as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. One potential outcome of this "dynamically driven double-degenerate double-detonation" (D-6) scenario is that the companion WD survives the explosion and is flung away with a velocity equal to its >1000 km s(-1) pre-SN orbital velocity. We perform a search for these hypervelocity runaway WDs using Gaia's second data release. In this paper, we discuss seven candidates followed up with ground-based instruments. Three sources are likely to be some of the fastest known stars in the Milky Way, with total Galactocentric velocities between 1000 and 3000 km s(-1), and are consistent with having previously been companion WDs in pre-SN. Ia systems. However, although the radial velocity of one of the stars is >1000 km s(-1), the radial velocities of the other two stars are puzzlingly consistent with 0. The combined five-parameter astrometric solutions from Gaia and radial velocities from follow-up spectra yield tentative 6D confirmation of the D-6 scenario. The past position of one of these stars places it within a faint, old SN remnant, further strengthening the interpretation of these candidates as hypervelocity runaways from binary systems that underwent SNe Ia.
VersionFinal published version
SponsorsNASA [NNX17AG28G, NNG17PX03C, NAS5-26555]; UK Science and Technology Facilities Council; NSF [AST-1615455, AST-1518052]; Gordon & Betty Moore Foundation; Heising-Simons Foundation; Alfred P. Sloan Foundation; David and Lucile Packard Foundation; Royal Society-Science Foundation Ireland University Research Fellowship; STFC; ESO Fellowship; Excellence Cluster Universe, Technische Universitat Munchen, Boltzmannstrasse, Garching, Germany; NASA - Space Telescope Science Institute [HST-HF2-51382.001-A]; Instrument Center for Danish Astrophysics (IDA); European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC ; National Aeronautics and Space Administration through the Planetary Science Division of the NASA Science Mission Directorate [NNX08AR22G]; National Science Foundation [AST-1238877]; ARC LIEF grant from the Australian Research Council [LE130100104]; Australian National University; Swinburne University of Technology; University of Queensland; University of Western Australia; University of Melbourne; Curtin University of Technology; Monash University; Australian Astronomical Observatory; Astronomy Australia Limited (AAL); Australian Government through the Commonwealth's Education Investment Fund (EIF); National Collaborative Research Infrastructure Strategy (NCRIS); National eResearch Collaboration Tools and Resources (NeCTAR); Australian National Data Service Projects (ANDS)