WD 1856 b: a close giant planet around a white dwarf that could have survived a common-envelope phase. (arXiv:2010.09747v2 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Lagos_F/0/1/0/all/0/1">F. Lagos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schreiber_M/0/1/0/all/0/1">M. R. Schreiber</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zorotovic_M/0/1/0/all/0/1">M. Zorotovic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gansicke_B/0/1/0/all/0/1">B. T. Gänsicke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ronco_M/0/1/0/all/0/1">M. P. Ronco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hamers_A/0/1/0/all/0/1">Adrian S. Hamers</a>
The discovery of a giant planet candidate orbiting the white dwarf WD
1856+534 with an orbital period of 1.4 d poses the questions of how the planet
reached its current position. We here reconstruct the evolutionary history of
the system assuming common envelope evolution as the main mechanism that
brought the planet to its current position. We find that common envelope
evolution can explain the present configuration if it was initiated when the
host star was on the AGB, the separation of the planet at the onset of mass
transfer was in the range 1.69-2.35 au, and if in addition to the orbital
energy of the surviving planet either recombination energy stored in the
envelope or another source of additional energy contributed to expelling the
envelope. We also discuss the evolution of the planet prior to and following
common envelope evolution. Finally, we find that if the system formed through
common envelope evolution, its total age is in agreement with its membership to
the Galactic thin disc. We therefore conclude that common envelope evolution is
at least as likely as alternative formation scenarios previously suggested such
as planet-planet scattering or Kozai-Lidov oscillations.
The discovery of a giant planet candidate orbiting the white dwarf WD
1856+534 with an orbital period of 1.4 d poses the questions of how the planet
reached its current position. We here reconstruct the evolutionary history of
the system assuming common envelope evolution as the main mechanism that
brought the planet to its current position. We find that common envelope
evolution can explain the present configuration if it was initiated when the
host star was on the AGB, the separation of the planet at the onset of mass
transfer was in the range 1.69-2.35 au, and if in addition to the orbital
energy of the surviving planet either recombination energy stored in the
envelope or another source of additional energy contributed to expelling the
envelope. We also discuss the evolution of the planet prior to and following
common envelope evolution. Finally, we find that if the system formed through
common envelope evolution, its total age is in agreement with its membership to
the Galactic thin disc. We therefore conclude that common envelope evolution is
at least as likely as alternative formation scenarios previously suggested such
as planet-planet scattering or Kozai-Lidov oscillations.
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