Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The Ancient China, ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categori ...

, a guest star () is a

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

which has suddenly appeared in a place where no star had previously been observed and becomes invisible again after some time. The term is a literal translation from ancient Chinese astronomical records. Modern astronomy recognizes that guest stars are manifestations of cataclysmic

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

nova A nova ( novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", Latin for "new") that slowly fades over weeks or months. All observed novae involve white ...

e and

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

e. The term "guest star" is used in the context of ancient records, since the exact classification of an astronomical event in question is based on interpretations of old records, including inference, rather than on direct observations. In ancient Chinese astronomy, guest stars were one of the three types of highly transient objects (bright heavenly bodies). The other two were comets with tails () and comets without tails (), with the former term being used for all comets in modern astronomy. The earliest Chinese record of guest stars is contained in '' Han Shu'' (漢書), the history of

Han dynasty The Han dynasty was an Dynasties of China, imperial dynasty of China (202 BC9 AD, 25–220 AD) established by Liu Bang and ruled by the House of Liu. The dynasty was preceded by the short-lived Qin dynasty (221–206 BC ...

(206 BC – AD 220), and all subsequent dynastic histories had such records.Zhentao Xu, David W. Pankenier (2000) "East-Asian

Archaeoastronomy Archaeoastronomy (also spelled archeoastronomy) is the interdisciplinary or multidisciplinary study of how people in the past "have understood the phenomena in the sky, how they used these phenomena and what role the sky played in their cultur ...

: Historical Records of Astronomical Observations of China, Japan, and Korea", , Chapter 6, "Guest Stars" These contain one of the clearest early descriptions consistent with a supernova, posited to be left over by object

SN 185 SN 185 was a transient astronomical event observed in the year AD 185, likely a supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolut ...

, thus identified as a supernova remnant of the exact year AD 185. Chronicles of the contemporary Europeans are more vague when consulted for supernovae candidates. Whether this was due to the weather or other reasons, astronomers have questioned why the remnant attributed to Chinese observations of a guest star in AD 1054 (see SN 1054) is missing from the European records.

References

{{supernovae Astronomical events Astronomy in China Cataclysmic variable stars

See also

References