Historical observations supplement modern theories on ancient supernova

National Geographic : Two recently discovered texts by ancient Arab scholars are providing new information on the brightest known supernova, SN 1006. In AD 1006 a transient celestial object was seen in the night sky. It blazed brightly over a period of several months and then disappeared. The event was recorded by early stargazers in Asia, the Middle East, and Europe. Now Ralph Neuhäuser of the Friedrich Schiller University Jena in Germany and his colleagues have discovered mention of SN 1006 in works by Persian scientist Ibn Sina and historian al-Yamani of Yemen. Sina’s account emphasizes the color evolution of the supernova event, which he says began as a faint greenish yellow, twinkled vigorously during peak brightness, then turned white before ultimately vanishing. The account by al-Yamani suggests that the supernova manifested itself earlier than many modern astronomers had thought, in mid April rather than at the end of the month. Although Sina’s description has been criticized because of the subjectivity of brightness observations, al-Yamani’s fixing of the date agrees with Neuhäuser’s own work.