Sharp images obtained by the Hubble Space Telescope confirm that three supernovae discovered several years ago exploded in the dark emptiness of intergalactic space, having been flung from their home galaxies millions or billions of years earlier.
Most supernovae are found inside galaxies containing hundreds of billions of stars, one of which might explode per century per galaxy.
These lonely supernovae, however, were found between galaxies in three large clusters of several thousand galaxies each. The stars' nearest neighbors were probably 300 light-years away, nearly 100 times farther than our sun's nearest stellar neighbor, Proxima Centauri, 4.24 light-years distant.
Graham and her colleagues -- David Sand of Texas Tech University, Dennis Zaritsky of the University of Arizona and Chris Pritchet of the University of Victoria in British Columbia -- will report their analysis of the three stars in a paper to be presented Friday, June 5, at a conference on supernovae at North Carolina State University in Raleigh. Their paper has also been accepted by the Astrophysical Journal.
