On Cas A, Cassini, Comets, and King Charles
Abstract
We re-examine the long-standing problem of the date of the Cassiopeia A supernova (SN), in view of recent claims that it might be the 1630 'noon-star' seen at the birth of King Charles II. We do not support this identification, based on the expected brightness of a Type-IIb SN (too faint to be seen in daylight), the extrapolated motion of the ejecta (inconsistent with a date earlier than 1650), the lack of any scientific follow-up observations, the lack of any mention of it in Asian archives. The origin of the 1630 noon-star event (if real) remains a mystery; there was a bright comet in 1630 June but no evidence to determine whether or not it was visible in daylight. Instead, we present French reports about a fourth-magnitude star discovered by Cassini in Cassiopeia in or shortly before 1671, which was not seen before or since. The brightness is consistent with what we expect for the Cas A SN; the date is consistent with the extrapolated motion of the ejecta. We argue that this source could be the long-sought SN.
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- March 2013
- DOI:
- 10.1017/pas.2013.003
- arXiv:
- arXiv:1301.1855
- Bibcode:
- 2013PASA...30...28S
- Keywords:
-
- atlases;
- history and philosophy of astronomy;
- supernovae: general;
- supernovae: individual: Cas A;
- Physics - History and Philosophy of Physics;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 10 pages, 0.8 MB. Accepted for publication in PASA. Slightly improved version thanks to suggestions from colleagues