In
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 Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the tw ...
, a guest star () is a
star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
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 with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as e ...
s:
nova
A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramat ...
e and
supernova
A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or whe ...
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
The ''Book of Han'' or ''History of the Former Han'' (Qián Hàn Shū,《前汉书》) is a history of China finished in 111AD, covering the Western, or Former Han dynasty from the first emperor in 206 BCE to the fall of Wang Mang in 23 CE. I ...
'' (漢書), the history of Han Dynasty
The Han dynasty (, ; ) was an Dynasties in Chinese history, imperial dynasty of China (202 BC – 9 AD, 25–220 AD), established by Emperor Gaozu of Han, Liu Bang (Emperor Gao) and ruled by the House of Liu. The dynasty was preceded by th ...
(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 cu ...
: 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. The transient occurred in the direction of Alpha Centauri, between the constellations Circinus and Centaurus, centered at RA Dec , in Circinus. This ...
, thus identified as a supernova remnant of the exact year AD 185.SN 1054
SN 1054 is a supernova that was first observed on 1054, and remained visible until 1056.
The event was recorded in contemporary Chinese astronomy, and references to it are also found in a later (13th-century) Japanese document, and in a docu ...
) is missing from the European records.[
]
See also
*
References
{{supernovae
Astronomical events
Astronomy in China
Cataclysmic variable stars