New Arabic Records From Cairo on Supernovae 1181 and 1006

Abstract

The remnant of the historical supernova SN 1181 is under discussion: While the previously suggested G130.7+3.1 (3C58) appears too old (3000–5000 year), the unusual star IRAS00500+6713 with a surrounding nebula (Pa-30) has an expansion age not inconsistent with a SN Iax explosion in ad 1181 under the assumption that neither acceleration nor deceleration occurred. Previously, only reports from China and Japan were known, pointing to an event near the northern circumpolar region. Any further reports from other cultures can therefore be highly relevant. We present here an Arabic poem in praise of Saladin by the contemporaneous author Ibn Sanā' al-Mulk (Cairo, Egypt). We re-date its composition to between Dec 1181 and May 1182. It contains a new bright star, which can be identified as SN 1181. The poem also provides new and independent information on the object type (called ‘najm’ for ‘star’), location on sky in or near the Arabic constellation al-Kaff al-Khaḍīb (lit. the henna-dyed hand, five bright stars in Cassiopeia), and brightness (brighter than (Formula presented.) Cas, 2.25 mag). In addition, we present another Arabic text on SN 1006, also from Cairo, by the historian al-Maqrīzī, probably based on the contemporaneous al-Musabbiḥī.