SN 2004dj
Encyclopedia
SN 2004dj was the brightest supernova
since SN 1987A
at the time of its discovery.
This Type II-P supernova was discovered by Koichi Itagaki, a Japan
ese astronomer
on July 31, 2004. At the time of its discovery, its apparent brightness was 11.2 visual magnitude
; the discovery occurred after the supernova had reached its peak magnitude. The supernova's progenitor is a star in a young, compact star cluster
in the galaxy
NGC 2403, in Camelopardalis
. The cluster had been cataloged as the 96th object in a list of luminous star
s and clusters by Allan Sandage
in 1984; the progenitor is therefore commonly referred to as Sandage 96. This cluster is easily visible in a Kitt Peak National Observatory
image and appears starlike.
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
since SN 1987A
SN 1987A
SN 1987A was a supernova in the outskirts of the Tarantula Nebula in the Large Magellanic Cloud, a nearby dwarf galaxy. It occurred approximately 51.4 kiloparsecs from Earth, approximately 168,000 light-years, close enough that it was visible to the naked eye. It could be seen from the Southern...
at the time of its discovery.
This Type II-P supernova was discovered by Koichi Itagaki, a Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
on July 31, 2004. At the time of its discovery, its apparent brightness was 11.2 visual magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
; the discovery occurred after the supernova had reached its peak magnitude. The supernova's progenitor is a star in a young, compact star cluster
Star cluster
Star clusters or star clouds are groups of stars. Two types of star clusters can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars which are gravitationally bound, while open clusters, more loosely clustered groups of stars, generally contain less than...
in the galaxy
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
NGC 2403, in Camelopardalis
Camelopardalis
Camelopardalis is a large but faint constellation in the northern sky. The constellation was introduced in 1612 by Petrus Plancius. Some older astronomy books give an alternative spelling of the name, Camelopardus.-Etymology:...
. The cluster had been cataloged as the 96th object in a list of luminous star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s and clusters by Allan Sandage
Allan Sandage
Allan Rex Sandage was an American astronomer. He was Staff Member Emeritus with the Carnegie Observatories in Pasadena, California. He is best known for determining the first reasonably accurate value for the Hubble constant and the age of the universe.-Career:Sandage was one of the most...
in 1984; the progenitor is therefore commonly referred to as Sandage 96. This cluster is easily visible in a Kitt Peak National Observatory
Kitt Peak National Observatory
The Kitt Peak National Observatory is a United States astronomical observatory located on 2,096 m Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, southwest of Tucson...
image and appears starlike.