Kavli Affiliate: Andrew Vanderburg
| First 5 Authors: Juliette Becker, Andrew Vanderburg, Joseph Livesey, ,
| Summary:
Several groups have recently suggested that small planets orbiting very
closely around white dwarf stars could be promising locations for life to
arise, even after stellar death. There are still many uncertainties, however,
regarding the existence and habitability of these worlds. Here, we consider the
retention of water during post-main-sequence evolution of a Sun-like star, and
during the subsequent migration of planets to the white dwarf’s habitable zone.
This inward migration is driven by dynamical mechanisms such as planet-planet
interactions in packed systems, which can excite planets to high
eccentricities, setting the initial conditions for tidal migration into
short-period orbits. In order for water to persist on the surfaces of planets
orbiting white dwarfs, the water must first survive the AGB phase of stellar
evolution, then avoid being lost due to photoevaporation due to X-ray and
extreme ultraviolet (XUV) radiation from the newly-formed white dwarf, and then
finally survive the tidal migration of the planet inwards to the habitable
zone. We find that while this journey will likely desiccate large swaths of
post-main-sequence planetary systems, planets with substantial reservoirs of
water may retain some surface water, especially if their migration occurs at
later white dwarf cooling ages. Therefore, although stellar evolution may pose
a challenge for the retention of water on exoplanet surfaces, it is possible
for planets to retain surface oceans even as their host stars die and their
orbits evolve.
| Search Query: ArXiv Query: search_query=au:”Andrew Vanderburg”&id_list=&start=0&max_results=3