Two delays in white dwarf evolution revealed by Gaia. (arXiv:2001.04483v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Cheng_S/0/1/0/all/0/1">Sihao Cheng</a>

By comparing two age indicators of high-mass white dwarfs derived from Gaia
data, two discoveries have been made recently: one is the existence of a
cooling anomaly that produces the Q branch structure on the
Hertzsprung–Russell diagram, the other is the existence of double-white-dwarf
merger products. The former poses a challenge for white dwarf cooling models,
and the latter has implications on binary evolution and type-Ia supernovae.

By comparing two age indicators of high-mass white dwarfs derived from Gaia
data, two discoveries have been made recently: one is the existence of a
cooling anomaly that produces the Q branch structure on the
Hertzsprung–Russell diagram, the other is the existence of double-white-dwarf
merger products. The former poses a challenge for white dwarf cooling models,
and the latter has implications on binary evolution and type-Ia supernovae.

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