[M81]

Supernova 1993J in M81

[M81 with SN 1993J, Greg Bothun] [PNG]

The supernova is the brighter star in the lower right.

This image was obtained in spring of 1993 at the Pine Mountain Observatory using a Lynxx PC CCD camera at the prime focus of the 32-inch telescope. From Greg Bothun's Messier collection.

  • More images from the University of Oregon collection

    This supernova occurred on Sunday, March 28, 1993, and was discovered by the Spanish amateur astronomer Francisco Garcia Diaz from Lugo (Spain). He discovered the supernova visually with his 10-inch Newtonian telescope at a magnification of 111, as an 11th magnitude star; it later reached a maximum brightness of about mag 10.5, around March 31, 1993.

    As the spectrum of SN 1993J exhibited only small amounts of hydrogen, it was soon suspected that large quantities of its outer envelop, up to 10 solar masses, had been "robbed" by a close companion star which should be discovered at one time. On May 28, 2002, the Hubble Space Telescope discovered the star in the predicted place, and spectra obtained with the Keck telescope in 2003 show absorption lines of the surviving companion in the spectrum of the faded supernova, indicating that this star has indeed "stolen" much hydrogen from the progenitor star in its supergiant phase of evolution (Maund et.al. 2004).

    Supernova 1993J was the second supernova where the progenitor star has been identified, after SN 1987A in the Large Magellanic Cloud.

    More on Supernova 1993J:

    References:

    Hartmut Frommert
    Christine Kronberg
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    Last Modification: August 29, 2005