Status Report

A disintegrating minor planet transiting a white dwarf

By SpaceRef Editor
October 22, 2015
Filed under , , ,

Andrew Vanderburg, John Asher Johnson, Saul Rappaport, Allyson Bieryla, Jonathan Irwin, John Arban Lewis, David Kipping, Warren R. Brown, Patrick Dufour, David R. Ciardi, Ruth Angus, Laura Schaefer, David W. Latham, David Charbonneau, Charles Beichman, Jason Eastman, Nate McCrady, Robert A. Wittenmyer, Jason T. Wright
(Submitted on 21 Oct 2015)

White dwarfs are the end state of most stars, including the Sun, after they exhaust their nuclear fuel. Between 1/4 and 1/2 of white dwarfs have elements heavier than helium in their atmospheres, even though these elements should rapidly settle into the stellar interiors unless they are occasionally replenished. The abundance ratios of heavy elements in white dwarf atmospheres are similar to rocky bodies in the Solar system. This and the existence of warm dusty debris disks around about 4% of white dwarfs suggest that rocky debris from white dwarf progenitors’ planetary systems occasionally pollute the stars’ atmospheres. The total accreted mass can be comparable to that of large asteroids in the solar system. However, the process of disrupting planetary material has not yet been observed. Here, we report observations of a white dwarf being transited by at least one and likely multiple disintegrating planetesimals with periods ranging from 4.5 hours to 4.9 hours. The strongest transit signals occur every 4.5 hours and exhibit varying depths up to 40% and asymmetric profiles, indicative of a small object with a cometary tail of dusty effluent material. The star hosts a dusty debris disk and the star’s spectrum shows prominent lines from heavy elements like magnesium, aluminium, silicon, calcium, iron, and nickel. This system provides evidence that heavy element pollution of white dwarfs can originate from disrupted rocky bodies such as asteroids and minor planets.
Comments: Published in Nature on October 22, 2015, available at this http URL . This is the authors’ version of the manuscript. 33 pages, 12 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Journal reference: Nature 526, 546-549 (22 October 2015)
DOI: 10.1038/nature15527
Cite as: arXiv:1510.06387 [astro-ph.EP] (or arXiv:1510.06387v1 [astro-ph.EP] for this version)
Submission history
From: Andrew Vanderburg
[v1] Wed, 21 Oct 2015 19:45:51 GMT (4523kb,D)

SpaceRef staff editor.