Planets or asteroids? A geochemical method to constrain the masses of White Dwarf pollutants
dc.contributor.author | Buchan, AM | |
dc.contributor.author | Bonsor, A | |
dc.contributor.author | Shorttle, O | |
dc.contributor.author | Wade, J | |
dc.contributor.author | Harrison, J | |
dc.contributor.author | Noack, L | |
dc.contributor.author | Koester, D | |
dc.date.accessioned | 2021-12-18T00:30:18Z | |
dc.date.available | 2021-12-18T00:30:18Z | |
dc.date.issued | 2022 | |
dc.identifier.issn | 0035-8711 | |
dc.identifier.uri | https://www.repository.cam.ac.uk/handle/1810/331599 | |
dc.description.abstract | Polluted white dwarfs that have accreted planetary material provide a unique opportunity to probe the geology of exoplanetary systems. However, the nature of the bodies which pollute white dwarfs is not well understood: are they small asteroids, minor planets, or even terrestrial planets? We present a novel method to infer pollutant masses from detections of Ni, Cr and Si. During core--mantle differentiation, these elements exhibit variable preference for metal and silicate at different pressures (i.e., object masses), affecting their abundances in the core and mantle. We model core--mantle differentiation self-consistently using data from metal--silicate partitioning experiments. We place statistical constraints on the differentiation pressures, and hence masses, of bodies which pollute white dwarfs by incorporating this calculation into a Bayesian framework. We show that Ni observations are best suited to constraining pressure when pollution is mantle-like, while Cr and Si are better for core-like pollution. We find 3 systems (WD0449-259, WD1350-162 and WD2105-820) whose abundances are best explained by the accretion of fragments of small parent bodies ($<0.2M_\oplus$). For 2 systems (GD61 and WD0446-255), the best model suggests the accretion of fragments of Earth-sized bodies, although the observed abundances remain consistent ($<3\sigma$) with the accretion of undifferentiated material. This suggests that polluted white dwarfs potentially accrete planetary bodies of a range of masses. However, our results are subject to inevitable degeneracies and limitations given current data. To constrain pressure more confidently, we require serendipitous observation of (nearly) pure core and/or mantle material. | |
dc.publisher | Oxford University Press (OUP) | |
dc.rights | All Rights Reserved | |
dc.rights.uri | http://www.rioxx.net/licenses/all-rights-reserved | |
dc.subject | planets and satellites: composition | |
dc.subject | planets and satellites: general | |
dc.subject | planets and satellites: interiors | |
dc.subject | planets and satellites: physical evolution | |
dc.subject | circumstellar matter | |
dc.subject | white dwarfs | |
dc.title | Planets or asteroids? A geochemical method to constrain the masses of White Dwarf pollutants | |
dc.type | Article | |
dc.publisher.department | Institute of Astronomy Student | |
dc.publisher.department | Institute of Astronomy | |
dc.date.updated | 2021-12-13T16:54:11Z | |
prism.publicationName | Monthly Notices of the Royal Astronomical Society | |
dc.identifier.doi | 10.17863/CAM.79051 | |
dcterms.dateAccepted | 2021-12-07 | |
rioxxterms.versionofrecord | 10.1093/mnras/stab3624 | |
rioxxterms.version | AM | |
dc.contributor.orcid | Buchan, AM [0000-0003-0105-5540] | |
dc.contributor.orcid | Bonsor, A [0000-0002-8070-1901] | |
dc.contributor.orcid | Harrison, J [0000-0002-9971-4956] | |
dc.contributor.orcid | Koester, D [0000-0002-6164-6978] | |
dc.identifier.eissn | 1365-2966 | |
dc.publisher.url | http://dx.doi.org/10.1093/mnras/stab3624 | |
rioxxterms.type | Journal Article/Review | |
cam.issuedOnline | 2021-12-21 | |
cam.orpheus.success | Tue Apr 12 08:22:26 BST 2022 - Embargo updated | |
cam.orpheus.counter | 4 | |
cam.depositDate | 2021-12-13 | |
pubs.licence-identifier | apollo-deposit-licence-2-1 | |
pubs.licence-display-name | Apollo Repository Deposit Licence Agreement | |
rioxxterms.freetoread.startdate | 2021-12-21 |
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