Historical Supernovae in the Galaxy from AD 1006

Abstract

The end points of evolution for some stars are supernova explosions, which release large amounts of energy and material into the surrounding interstellar medium. This energy and material then produces a supernova remnant, of which nearly three hundred have been identified in our Galaxy. The expected rate of supernovae in our Galaxy is approximately two per century, although most will be too far away to be have been observed optically, due to obscuration along the line-of-sight through the Galactic disk. However, supernovae which are relatively nearby are expected to be visible optically, even with the naked eye. Over the last 1000 years or so there are definite historical records of five supernovae in our Galaxy – in AD 1006, 1054, 1181, 1572 and 1604 – that have been observed, all in the pre-telescopic era. The majority of the historical records of these supernovae are from East Asia (i.e., China, Japan and Korea). In addition, detailed European records are available for the most recent two supernovae, and there are also a variety of Arabic records available for some of these events. The records of these five “historical” supernovae are reviewed here, along with a brief discussion of the supernova remnants produced by them. The historical observations of these five supernova allow quantitative astrophysical studies of their remnants, since their ages are known precisely. Also discussed briefly are observations from AD 1680 which have been proposed as being from the supernova that produced the well-known and young supernova remnant Cassiopeia A.