First observed between August 4 and August 6, 1181, Chinese and Japanese astronomers recorded the supernova now known as SN 1181 in eight separate texts. One of only nine supernovae in the Milky Way observable with the naked eye in recorded history, it appeared in the constellation Cassiopeia and was visible in the night sky for about 185 days.
The radio and X-ray pulsar J0205+6449 (also known as 3C 58), which rotates about 15 times per second, has previously been identified as the possible remnant from this event. If the supernova and pulsar are associated, the star is still rotating about as quickly as it did when it first formed. This is in contrast to the Crab pulsar, known to be the remnant of the SN 1054supernova in the year 1054, which has lost two-thirds of its rotational energy in essentially the same time span. A paper published in 2006, of radio surveys of 3C 58, however, indicated that this supernova remnant may be much older and thus not associated with SN 1181.
In 2021, a team of astronomers led by Andreas Ritter and Quentin Parker from the University of Hong Kong announced the discovery of a more likely SN 1181 candidate: an extremely hot Wolf Rayet star dubbed Parker’s Star (J005311 / IRAS 00500+6713) which is surrounded by a gaseous nebula named Pa 30 (Patchick 30) approximately 0.9 parsecs wide and expanding at 1100 kilometers per second. The measurements are based on an estimated distance of 3,000 parsecs based on GAIA data for the star. The observed properties of Pa 30 suggests it is the remnant of SN 1181 which apparently was a rare Type Iax supernova not resulting in the complete destruction of the merged progenitor stars. Hence J005311/Parker’s Star is likely a so-called “zombie star“.
The nebula was first detected on August 25, 2013 by American amateur astronomer Dana Patchick in WISE mid-infrared imagery as a Planetary Nebula candidate. In addition to the WISE detection of Pa 30, the bright central star (Mg. 15.4) was discovered moments later through the use of the Galexview application that supported searching of GALEX image tiles.  The nuv source (near ultra violet) spotted there matched with cataloged star UCAC4 788-002438.  The Galex detection and UCAC4 788-002438 are alternative designations for IRAS 00500+6713, itself known since 1986.
Images secured in early September 2013 with the 2.1M KPNO reflector  under the direction of Dr. George Jacoby revealed an unusually faint shell in narrow-band [OIII] imagery surrounding the Mg. 15.4 central star. Taken together, Pa 30 was recorded in the HASH database as a ‘likely PN’, until September 30, 2021 when the status was upgraded to ‘Supernova Remnant’. 
In 2018, preliminary spectra of the hot central star by French amateur astronomer Pascal Le Dû revealed unique spectral lines that were brought to the attention of professional collaborator Prof. Quentin Parker and colleagues who had independently observed the nebula and star with the 10m Grantecan Telescope on La Palma in 2017. It was this data which revealed the faint [SII] nebula lines from Pa30 and allowed the extreme expansion velocity to be measured. This helped speed up the discovery process.
- “SN 1181”. SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 5, 2013.
- Green, D. A. (2002). “Historical Supernovae and their Remnants”. Highlights of Astronomy. 12: 350–353. doi:10.1017/S1539299600013721. ISSN 1539-2996.
- Panagia, N.; Weiler, K. W. (1980). “The absolute magnitude and the type classification of SN 1181 equals 3 C 58”. Astronomy and Astrophysics. 82 (3): 389–391. Bibcode:1980A&A….82..389P.
- Galas, C. M. F.; Tuohy, I. R.; Garmire, G. P. (1980). “Soft X-ray observations of the supernova remnants HB 3 and 3C 58”. The Astrophysical Journal Letters. 236: L13–L16. Bibcode:1980ApJ…236L..13G. doi:10.1086/183188.
- Bietenholz, M. F. (2006). “Radio Images of 3C 58: Expansion and Motion of Its Wisp”(PDF). The Astrophysical Journal. 645 (2): 1180–1187. arXiv:astro-ph/0603197. Bibcode:2006ApJ…645.1180B. doi:10.1086/504584.
- Ritter, A.; Parker, Q. A.; Lykou, F.; Zijlstra, A. A.; Guerrero, M. A.; Le Dû, P. “The Remnant and Origin of the Historical Supernova 1181 AD”. arXiv:2105.12384. doi:10.3847/2041-8213/ac2253. Cite journal requires
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- “Planetary Nebulae.net”.
- “NGC 2336”.
- “UCAC4 Catalogue (Zacharias+, 2012)”.
- “IRAS Catalogue of Point Sources, Version 2.0 (IPAC 1986)”.
- “Kitt Peak 2.1 Meter Telescope”.
- “HASH PN Database”.
- “Planetary Nebulae.net”.