Double-White-Dwarf Merger Products among High-Mass White Dwarfs [SSA]

http://arxiv.org/abs/1910.09558


Double-white-dwarf (double-WD) binaries may merge within a Hubble time and produce high-mass WDs. Compared to other high-mass WDs, the double-WD merger products have higher velocity dispersion because they are older. With the power of Gaia data, we show strong evidence for double-WD merger products among high-mass WDs by analyzing the transverse-velocity distribution of more than a thousand high-mass WDs (0.8-1.3 $M_\odot$). We estimate that the fraction of double-WD merger products in our sample is about 20 %. We also calculate the double-WD merger rate and its mass dependence. Our results agree with binary population synthesis results and support the idea that double-WD mergers can contribute to a large fraction of type-Ia supernovae.

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S. Cheng, J. Cummings, B. Ménard, et. al.
Wed, 23 Oct 19
27/64

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