Herschel finds enormous stores of dust in supernova 1987A

Supernova (SN) 1987A continues to surprise us. It exploded in February 1987 as a blue supergiant, not a red one, and it later displayed three circumstellar rings whose origin are still not completely understood. The latest finding is that between 160,000 and 230,000 Earth masses of dust may have been created since the explosion in 1987. It has been known from other core-collapse supernovae that they can produce of order 100 Earth masses of dust, but that another factor of 1000 was possible came as a complete surprise. The detection of the dust was made possible with the Herschel Space Observatory, which operates in the very far infrared, and is sensible to cold dust. Herschel detected SN 1987A in 2010 as part of a survey of the Magellanic Clouds. The detection was made in several wavelength bands, and the emission in those bands forms a spectrum which is the same as emission from very cold dust with a temperature of around 20 K. The finding was reported last week in a paper in Science with Mikako Matsuura (University College London) as first author, and OKC-member Peter Lundqvist as one of the co-authors. The detection of the high dust mass can explain why dust exists in high redshift galaxies. If core-collapse supernovae, which all die fairly young, can produce this much dust, they would be the main producers of dust in the early Universe, and perhaps also at later epochs. It has long been an open question whether supernovae, or dust from less massive stars at their late stages of evolution are the main dust factories in the Universe. Refined observations are going to be made with Herschel to test the first, so we will soon have the full answer to the origin of the emission detected by Matsuura et al.

SN1987A Herschel image
The area of SN 1987A as seen by Herschel and Hubble Space Telescope. Den circle in the Herschel image has been enlarged to the right to better show all the details in Hubble image. The dot in the middle of the Herschel image is SN 1987A.

The article M. Matsuura et al. 2011, To appear in Science is available in Science Express on 7th July, DOI:10.1126/science.1205983 and online at http://www.sciencemag.org/content/early/2011/07/06/science.1205983 or in the arXiv:1107.1477

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