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dc.contributor.authorBuchan, Andrew
dc.contributor.authorBonsor-Matthews, Amy
dc.contributor.authorShorttle, Oliver
dc.contributor.authorWade, Jon
dc.contributor.authorHarrison, John
dc.contributor.authorNoack, Lena
dc.contributor.authorKoester, Detlev
dc.date.accessioned2021-12-18T00:30:18Z
dc.date.available2021-12-18T00:30:18Z
dc.date.issued2022-03
dc.identifier.issn0035-8711
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/331599
dc.description.abstractPolluted 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.publisherOxford University Press (OUP)
dc.rightsAll Rights Reserved
dc.rights.urihttp://www.rioxx.net/licenses/all-rights-reserved
dc.subjectastro-ph.EP
dc.subjectastro-ph.EP
dc.subjectastro-ph.SR
dc.titlePlanets or asteroids? A geochemical method to constrain the masses of White Dwarf pollutants
dc.typeArticle
dc.publisher.departmentInstitute of Astronomy Student
dc.publisher.departmentInstitute of Astronomy
dc.date.updated2021-12-13T16:54:11Z
prism.publicationNameMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
dc.identifier.doi10.17863/CAM.79051
dcterms.dateAccepted2021-12-07
rioxxterms.versionofrecord10.1093/mnras/stab3624
rioxxterms.versionAM
dc.contributor.orcidBuchan, Andrew [0000-0003-0105-5540]
dc.contributor.orcidBonsor-Matthews, Amy [0000-0002-8070-1901]
dc.contributor.orcidShorttle, Oliver [0000-0002-8713-1446]
dc.identifier.eissn1365-2966
dc.publisher.urlhttp://dx.doi.org/10.1093/mnras/stab3624
rioxxterms.typeJournal Article/Review
cam.issuedOnline2021-12-21
cam.orpheus.successTue Apr 12 08:22:26 BST 2022 - Embargo updated
cam.orpheus.counter4
cam.depositDate2021-12-13
pubs.licence-identifierapollo-deposit-licence-2-1
pubs.licence-display-nameApollo Repository Deposit Licence Agreement
rioxxterms.freetoread.startdate2021-12-21


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