SN 185 was a
transient astronomical event
The asterisk ( ), from Late Latin , from Ancient Greek , ''asteriskos'', "little star", is a typographical symbol. It is so called because it resembles a conventional image of a heraldic star.
Computer scientists and mathematicians often voc ...
observed in the year
AD 185
Year 185 ( CLXXXV) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Lascivius and Atilius (or, less frequently, year 938 ''Ab urbe con ...
, likely a
supernova. The transient occurred in the direction of
Alpha Centauri, between the constellations
Circinus and
Centaurus, centered at
RA Dec , in Circinus. This "
guest star" was observed by
Chinese astronomers in the ''
Book of Later Han'' (后汉书), and might have been recorded in
Roman literature.
It remained visible in the night sky for eight months. This is believed to be the first supernova for which records exist.
History
''The Book of Later Han'' gives the following description:
In the 2nd year of the epoch Zhongping ��平 the 10th month, on the day Guihai ��亥 ecember 7, Year 185 a ' guest star' appeared in the middle of the Southern Gate ��門 ε Centauri and Alpha Centauri">α Centauri">Epsilon Centauri">ε Centauri and Alpha Centauri">α Centauri The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise. It gradually lessened. In the 6th month of the succeeding year it disappeared.
The gaseous shell
RCW 86 is probably the supernova remnant">RCW Catalogue">RCW 86 is probably the supernova remnant of this event and has a relatively large angular size of roughly 45 arc minutes
(larger than the apparent size of the full moon, which varies from 29 to 34 arc minutes). The distance to RCW 86 is estimated to be .
[ Recent X-ray studies show a good match for the expected age.]Type Ia
A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white ...
supernova (a type with consistent absolute magnitude),Tycho's Supernova
SN 1572 (''Tycho's Supernova'', ''Tycho's Nova''), or B Cassiopeiae (B Cas), was a supernova of Type Ia in the constellation Cassiopeia, one of eight supernovae visible to the naked eye in historical records. It appeared in early November 1572 a ...
(SN 1572), which had apparent magnitude −4 at a similar distance.
See also
* List of supernovae
* History of supernova observation
* List of supernova remnants
* List of supernova candidates
References
External links
*
*
BBC News
– Ancient supernova mystery solved (25 October 2011)
{{DEFAULTSORT:Sn 185
185
Centaurus (constellation)
Circinus (constellation)
Supernova remnants
85
2nd-century natural events
Historical supernovae