A disintegrating minor planet transiting a white dwarf

Vanderburg, Andrew and Johnson, John Asher and Rappaport, Saul and Bieryla, Allyson and Irwin, Jonathan and Lewis, John Arban and Kipping, David and Brown, Warren R. and Dufour, Patrick and Ciardi, David R. and Angus, Ruth and Schaefer, Laura and Latham, David W. and Charbonneau, David and Beichman, Charles and Eastman, Jason and McCrady, Nate and Wittenmyer, Robert A. and Wright, Jason T. (2015) A disintegrating minor planet transiting a white dwarf. Nature, 526 (7574). pp. 546-549. ISSN 0028-0836

Abstract

Most stars become white dwarfs after they have exhausted their nuclear fuel (the Sun will be one such). Between one-quarter and one-half of white dwarfs have elements heavier than helium in their atmospheres, even though these elements ought to sink rapidly into the stellar interiors (unless they are occasionally replenished). The abundance ratios of heavy elements in the atmospheres of white dwarfs are similar to the ratios in rocky bodies in the Solar System. This fact, together with the existence of warm, dusty debris disks surrounding about four per cent of white dwarfs, suggests that rocky debris from the planetary systems of white-dwarf progenitors occasionally pollutes the atmospheres of the stars. The total accreted mass of this debris is sometimes comparable to the mass of large asteroids in the Solar System. However, rocky, disintegrating bodies around a white dwarf have not yet been observed. Here we report observations of a white dwarf - WD 1145+017 - being transited by at least one, and probably several, 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 (blocking up to 40 per cent of the star's brightness) and asymmetric profiles, indicative of a small object with a cometary tail of dusty effluent material. The star has a dusty debris disk, and the star's spectrum shows prominent lines from heavy elements such as magnesium, aluminium, silicon, calcium, iron, and nickel. This system provides further evidence that the pollution of white dwarfs by heavy elements might originate from disrupted rocky bodies such as asteroids and minor planets.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version due to publisher copyright policy.
Faculty / Department / School: No Faculty
Date Deposited: 10 May 2017 23:41
Last Modified: 02 Nov 2017 04:34
Uncontrolled Keywords: astronomy; brightness; dust; spectrum
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1038/nature15527
URI: http://eprints.usq.edu.au/id/eprint/31752

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