Publication Date:
2015-10-23
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vanderburg, Andrew -- Johnson, John Asher -- Rappaport, Saul -- Bieryla, Allyson -- Irwin, Jonathan -- Lewis, John Arban -- Kipping, David -- Brown, Warren R -- Dufour, Patrick -- Ciardi, David R -- Angus, Ruth -- Schaefer, Laura -- Latham, David W -- Charbonneau, David -- Beichman, Charles -- Eastman, Jason -- McCrady, Nate -- Wittenmyer, Robert A -- Wright, Jason T -- England -- Nature. 2015 Oct 22;526(7574):546-9. doi: 10.1038/nature15527.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA. ; Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. ; Department of Astronomy, Columbia University, New York, New York 10027, USA. ; Institut de Recherche sur les Exoplanetes, Department de Physique, Universite de Montreal, Montreal, Quebec H3C 3J7, Canada. ; NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, California 91125, USA. ; Department of Physics, University of Oxford, Oxford OX1 3RH, UK. ; Department of Physics and Astronomy, University of Montana, Missoula, Montana 59812, USA. ; School of Physics and Australian Centre for Astrobiology, University of New South Wales, Sydney, New South Wales 2052, Australia. ; Department of Astronomy and Astrophysics and Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26490620" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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