* Astronomy

In a paper published in the March 19, 2009 issue of Science Express, Justyn Maund and Stephen Smartt present data from the Gemini Observatory and Hubble Space Telescope (HST) that confirms the disappearance of the progenitors of two Type II supernovae (SNe).
The only other supernova progenitor of this sort known to have definitively disappeared was SN 1987A in the Large Magellanic Cloud, part of our Local Group of Galaxies. Because the identity of the stars found in pre-explosion images has now been confirmed, this work provides the important "nail in the coffin" that the now missing Red Supergiants were the progenitors.
The two supernovae, denoted 1993J and 2003gd, both had confirmed pre-existing progenitors identified from archival data which allowed the researchers to compare pre-supernova identification of the progenitor star with post-supernova observations. Maund and Smartt used a technique where images were taken after SN 2003gd had faded away, and the progenitor star was presumably missing, and subtracted from the pre-explosion images.  Anything left over at the SN position corresponded to the real progenitor star.

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