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On Cas A, Cassini, Comets, and King Charles


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.

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Arcavi I., et al. 2010, ApJ, 721, 777
Arcavi I., et al. 2011, ApJ, 742, L18
Ashworth W. B. 1980, JHA, 11, 1
Barbon R., Buondí V., Cappellaro E., & Turatto M. 1999, A&AS, 139, 531
Bayer J. 1603, in Uranometria: Omnium asterismorum continens schemata, nova methodo delineata, aereis laminis expressa, (Augsburg, Germany: C. Mangus)
Beijing Astronomical Observatory [BAO] (Chief editor) 1988, Zhong guo gu dai tian xiang ji lu zong ji (Nanjing: Jiangsu Science and Technology Publishing)
Bembrick C., Pearce A., & Evans R. 2002, IAUC, 7804, 2
Brahe T. 1573, in De nova et nullius aevi memoria prius visa stella iam pridem anno a nato Christo 1572, mense Novembri primum conspecta, contemplatio mathematica (Copenhagen: Laurentius Benedictus)
Brown M. A. 2010, in The Pleiadic Age of Stuart Poesie: Restoration Uranography, Dryden's Judicial Astrology, and the Fate of Anne Killigrew, English theses (Georgia State University), 49
Cassini J. [Cassini II] 1740, in Elemens d’astronomie (Paris: Imprimerie Royale), 72
Cassini IV J.-D. 1810, in Mémoires pour servir à l’Histoire des Sciences et à celle de l’Observatoire Royal de Paris, suivis de la vie de J.-D. Cassini, écrite par lui-même, et des éloges de plusieurs Académiciens morts pendant la Révolution (Paris: Bleuet), 289
Claeys J. S. W., de Mink S. E., Pols O. R., Eldridge J. J., & Baes M. 2011, A&A, 528, 131
Dreschhoff G. A. M., & Laird C. M. 2006, AdSpRes, 38, 1307
Dreschhoff G. A. M., & Zeller E. J. 1990, Sol. Phys., 127, 333
Fesen R. A., et al. 2006, ApJ, 645, 283
French P. 2007, in North Korea: The Paranoid Peninsula: A Modern History (London: Zed Books), 57
Gallois J. 1668, ‘Apparizioni celesti dell’anno 1668 osservate in Bologna da Gio. Domenico Cassini Astronomo dello studio publico’, J. Sçavans, 57
Gallois J. 1671, ‘Observation d’une étoile nouvellement découverte proche la Constellation du Cygne’, J. Sçavans, 32
Green D. A., & Stephenson F. R. 2003, LNP, 598, 7
Kamper K. W. 1980, Obs, 100, 3
Krause O., Birkmann S. M., Usuda T., Hattori T., Goto M., Rieke G. H., & Misselt K. A. 2008, Sci, 320, 1195
Kronk G. W. 1999, Cometography: A Catalog of Comets, Vol. 1: Ancient–1799 (Cambridge: Cambridge University Press)
Lynn W. T. 1894, Obs, 17, 272
Maraldi G. F. 1694, “Sur les changemens de grandeur apparente des Etoiles”, in Histoire & Mémoires de l’Académie Royale des Sciences. Depuis 1666 jusq’à 1699, 2, 222
McCracken K. G., Dreschhoff G. A. M., Zeller E. J., Smart D. F., & Shea M. A. 2001, J. Geophys. Res., 106, 21599
Melott A. L., & Thomas B. C. 2011, Astrobiology, 11, 343
Motizuki Y., Nakai Y., & Takahashi K. 2010, Highlights Astron., 15, 630
Motizuki Y., et al. 2009, arXiv:0902.3446
Nomoto K., et al. 1993, Natur, 364, 507
Pastorello A. 2008, MNRAS, 389, 955
Podsiadlowski P., Hsu J. J. L., Joss P. C., & Ross R. R. 1993, Natur, 364, 509
Qiu Y., Li W., Qiao Q., & Hu J. 1999, AJ, 117, 736
Reed J. E., Hester J. J., Fabian A. C., & Winkler P. F. 1995, ApJ, 440, 706
Richardson D., Branch D., & Baron E. 2006, AJ, 131, 2233
Richardson D., Branch D., Casebeer D., Millard J., Thomas R. C., & Baron E. 2002, AJ, 123, 745
Ripamonti G. 1640, in ‘De peste quae fuit anno MDCXXX’ (Mediolani: Malatestas, Regios ac Ducales Typographos), 110, 273
Risbo T., Clausen H. B., & Rasmussen K. L. 1981, Natur, 294, 637
Rood R. T., Sarazin C. L., Zeller E. J., & Parker B. C. 1979, Natur, 282, 701
Sauval J. 1997, Longest Visibility of Ancient Comets, unpublished report available online at
Schiller J. 1627, in Coelum Stellatum Christianum’, (Augsburg, Germany: A. Apergerus)
Schlafly E. F., & Finkbeiner D. P. 2011, ApJ, 737, 103
Schmidt B. P., et al. 1993, Natur, 364, 600
Smartt S. J. 2009, ARA&A, 47, 63
Smith N., Li W., Filippenko A. V., & Chornock R. 2011, MNRAS, 412, 1522
Stählin von Storcksburg J. 1788, in Original Anecdotes of Peter the Great: Collected from the Conversation of Several Persons of Distinction at Petersburgh and Moscow, (London: J. Murray, J. Sewell, & W. Creech), 395
Stephenson F. R., & Green D. A. 2002, in Historical Supernovae and Their Remnants, International Series in Astronomy and Astrophysics (Oxford: Clarendon Press), 5
Stephenson F. R., & Green D. A. 2005a, JHA, 36, 217
Stephenson F. R., & Green D. A. 2005b, ASPC, 342, 63
Strom R. 2002, A&A, 387, L17
Tadini A. 1648, in Ragguaglio dell’Origine et Giornali Successi della Gran peste Contagiosa Venefica et Malefica seguita in Milano e suo Ducato dall’anno 1629 al 1631’, (Milan: F. Ghisolfi)
Thorstensen J. R., Fesen R. A. & van den Bergh S. 2001, AJ, 122, 297
van Leeuwen F. 2007, A&A, 474, 653
Zeller E. J., & Dreschhoff G. A. M. 1995, Geophys. Res. Lett., 22, 2521
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