Compositions of Planetary Debris around Dusty White Dwarfs

The photospheres of some white dwarfs (WDs) are "polluted" by accretion of material from their surrounding planetary debris. WDs with dust disks are often heavily polluted and high-resolution spectroscopic observations of these systems can be used to infer the chemical compositions of extr...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:The Astronomical journal 2019-12, Vol.158 (6), p.242
Hauptverfasser: Xu, Siyi, Dufour, Patrick, Klein, Beth, Melis, Carl, Monson, Nathaniel N., Zuckerman, B., Young, Edward D., Jura, Michael A.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext bestellen
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:The photospheres of some white dwarfs (WDs) are "polluted" by accretion of material from their surrounding planetary debris. WDs with dust disks are often heavily polluted and high-resolution spectroscopic observations of these systems can be used to infer the chemical compositions of extrasolar planetary material. Here, we report spectroscopic observation and analysis of 19 WDs with dust disks or candidate disks. The overall abundance pattern very much resembles that of bulk Earth and we are starting to build a large enough sample to probe a wide range of planetary compositions. We found evidence for accretion of Fe-rich material onto two WDs as well as O-rich but H-poor planetary debris onto one WD. In addition, there is a spread in Mg/Ca and Si/Ca ratios and it cannot be explained by differential settling or igneous differentiation. The ratios appear to follow an evaporation sequence. In this scenario, we can constrain the mass and number of evaporating bodies surrounding polluted WDs.
ISSN:0004-6256
1538-3881
DOI:10.3847/1538-3881/ab4cee