The Gaia-ESO Survey: chemical signatures of rocky accretion in a young solar-type star

Journal
Date Issued
2015
Author(s)
Spina, L.
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Palla, F.
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•
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Jeffries, R.
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•
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Meyer, M. R.
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Tautvaišienė, G.
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Gilmore, G.
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Alfaro, E. J.
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Allende Prieto, C.
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Bensby, T.
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•
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Koposov, S. E.
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Costado, M. T.
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Hourihane, A.
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Lardo, C.
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Lewis, J.
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Monaco, L.
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Sousa, S. G.
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Worley, C. C.
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DOI
Description
Based on data products from observations made with ESO telescopes at the La Silla Paranal Observatory under program ID 188.B-3002. These data products have been processed by the Cambridge Astronomy Survey Unit (CASU) at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the Gaia -ESO Survey Data Archive, prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council. This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and the Ministero dell’ Istruzione, dell’ Università’ e della Ricerca (MIUR) in the form of the grant “Premiale VLT 2012” and “The Chemical and Dynamical Evolution of the Milky Way and Local Group Galaxies” (prot. 2010LY5N2T). The results presented here benefit from discussions held during the Gaia -ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. L.S. acknowledges the support from FAPESP (2014/15706-9) and gratefully thanks J. Meléndez for helpful discussions. M.R.M. acknowledges support from the Swiss National Science Foundation (SNF).
Abstract
It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or protoplanetary objects may accrete onto the central star, being fused and mixed into its external layers. If the accreted mass is sufficiently high and the star has a sufficiently thin convective envelope, such events may result in a modification of the chemical composition of the stellar photosphere in an observable way, enhancing it with elements that were abundant in the accreted mass. The recent Gaia-ESO Survey observations of the 10-20 Myr old Gamma Velorum cluster have enabled identifying a star that is significantly enriched in iron with respect to other cluster members. In this Letter we further investigate the abundance pattern of this star, showing that its abundance anomaly is not limited to iron, but is also present in the refractory elements, whose overabundances are correlated with the condensation temperature. This finding strongly supports the hypothesis of a recent accretion of rocky material.

Based on observations made with the ESO/VLT, at Paranal Observatory, under program 188.B-3002 (The Gaia-ESO Public Spectroscopic Survey).

Volume
582
Start page
L6
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2015A&A...582L...6S
Rights
open.access
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