S Andromedae

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S Andromedae (also SN 1885A) was a 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...

 in the Andromeda Galaxy
Andromeda Galaxy
The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years from Earth in the constellation Andromeda. It is also known as Messier 31, M31, or NGC 224, and is often referred to as the Great Andromeda Nebula in older texts. Andromeda is the nearest spiral galaxy to the...

, the only one seen in that 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...

 so far by astronomers, and the first ever noted outside the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

. It is also known as "Supernova 1885".

It was discovered on August 19, 1885, by the Irish amateur astronomer Isaac Ward in Belfast
Belfast is the capital of and largest city in Northern Ireland. By population, it is the 14th biggest city in the United Kingdom and second biggest on the island of Ireland . It is the seat of the devolved government and legislative Northern Ireland Assembly...

, and independently the following day by Ernst Hartwig
Ernst Hartwig
Carl Ernst Albrecht Hartwig was a German astronomer.He discovered a new star in M31 on August 20, 1885. This object was designated as supernova "S Andromedae". During the 1883 observation campaign of comet 6P/d'Arrest he found five NGC objects working at the Strasbourg Observatory...

 at Dorpat (Tartu) Observatory
Tartu Observatory
The Tartu Observatory is the largest astronomical observatory in Estonia. It is located on the Tõravere hill, about 20 km south-west of Tartu in Nõo Parish, Tartu County...

 in Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

. It reached magnitude 6, but faded to magnitude 16 by 1 st February 1886.

The star was reported to be reddish in color and declined very rapidly in brightness, which is atypical for Type Ia supernovae. Unfortunately no spectroscopic data is available.

The location of the supernova event was 16″ from the relatively bright nucleus of the galaxy. This made detection of the supernova remnant difficult, and multiple attempts proved unsuccessful. Finally, in 1988, astronomer R. A. Fesen and others using the 4-meter Mayall telescope
Nicholas U. Mayall Telescope
The Nicholas U. Mayall Telescope is a four meter reflector telescope located at the Kitt Peak National Observatory and named after Nicholas U. Mayall. It saw first light on February 27, 1973. Initial observers included: D. Crawford, Nicholas Mayall, and Arthur Hoag. It was dedicated on June 20,...

 at Kitt Peak
Kitt Peak
Kitt Peak is a mountain in the U.S. state of Arizona. It is the location of the Kitt Peak National Observatory. The radio telescope at the Observatory is one of ten dishes comprising the Very Long Baseline Array ....

 discovered the iron-rich remnant of the explosion. Further observations were made with the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

in 1995.
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