Host-star and exoplanet compositions: a pilot study usinga wide binary with a polluted white dwarf. (arXiv:2102.02843v2 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Bonsor_A/0/1/0/all/0/1">Amy Bonsor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jofre_P/0/1/0/all/0/1">Paula Jofre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shorttle_O/0/1/0/all/0/1">Oliver Shorttle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rogers_L/0/1/0/all/0/1">Laura K Rogers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_S/0/1/0/all/0/1">Siyi Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Melis_C/0/1/0/all/0/1">Carl Melis</a>
Planets and stars ultimately form out of the collapse of the same cloud of
gas. Whilst planets, and planetary bodies, readily loose volatiles, a common
hypothesis is that they retain the same refractory composition as their host
star. This is true within the Solar System. The refractory composition of
chondritic meteorites, Earth and other rocky planetary bodies are consistent
with solar, within the observational errors. This work aims to investigate
whether this hypothesis holds for exoplanetary systems. If true, the internal
structure of observed rocky exoplanets can be better constrained using their
host star abundances. In this paper, we analyse the abundances of the K-dwarf,
G200-40, and compare them to its polluted white dwarf companion, WD 1425+540.
The white dwarf has accreted planetary material, most probably a Kuiper
belt-like object, from an outer planetary system surviving the star’s evolution
to the white dwarf phase. Given that binary pairs are chemically homogeneous,
we use the binary companion, G200-40, as a proxy for the composition of the
progenitor to WD 1425+540. We show that the elemental abundances of the
companion star and the planetary material accreted by WD 1425+540 are
consistent with the hypothesis that planet and host-stars have the same true
abundances, taking into account the observational errors.
Planets and stars ultimately form out of the collapse of the same cloud of
gas. Whilst planets, and planetary bodies, readily loose volatiles, a common
hypothesis is that they retain the same refractory composition as their host
star. This is true within the Solar System. The refractory composition of
chondritic meteorites, Earth and other rocky planetary bodies are consistent
with solar, within the observational errors. This work aims to investigate
whether this hypothesis holds for exoplanetary systems. If true, the internal
structure of observed rocky exoplanets can be better constrained using their
host star abundances. In this paper, we analyse the abundances of the K-dwarf,
G200-40, and compare them to its polluted white dwarf companion, WD 1425+540.
The white dwarf has accreted planetary material, most probably a Kuiper
belt-like object, from an outer planetary system surviving the star’s evolution
to the white dwarf phase. Given that binary pairs are chemically homogeneous,
we use the binary companion, G200-40, as a proxy for the composition of the
progenitor to WD 1425+540. We show that the elemental abundances of the
companion star and the planetary material accreted by WD 1425+540 are
consistent with the hypothesis that planet and host-stars have the same true
abundances, taking into account the observational errors.
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