U Scorpii (''U Sco'') is a recurrent

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 dramati ...

system; one of 10 known recurring novae in the

Milky Way galaxy The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

. Located near the northern edge of the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Scorpius Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Gre ...

it normally has a

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of 18, but reaches a magnitude of about 8 during outbursts. Outbursts have been observed in 1863, 1906, 1936, 1979, 1987, 1999, 2010, and 2022. The 2010 outburst was predicted to occur April 2009 ± 1.0 year, based on observations during quiescence following the 1999 outburst. The U Sco 2010 eruption faded by 1 magnitude in 1 day, and by 4 magnitudes in 6 days. By February 6 it was dimmer than magnitude 13. Between February 10–19, it was flickering around magnitude 14. The eruption ended on day 64, which is the fastest observed decline to quiescence of recurring nova. This eruption of U Sco is now the best-observed nova event with 22,000 magnitudes already accumulated. Astronomers have predicted that another eruption of U Sco will occur in 2020±2. This prediction was correct; it brightened to +7.8 magnitude on 6 June 2022. U-Sco-2010-Lightcurve-AAVSO

Originally identified in 1863 by English astronomer N.R. Pogson, U Scorpii was the third recurrent nova to be identified, in the years preceding

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

by Helen L. Thomas.

References

External links

* http://www.phys.lsu.edu/dept/people/schaefer.html
U Scorpii in Outburst

Long-term monitoring of the recurrent nova U Scorpii
(AAVSO 2010 April 9) * AAVSO
Quick Look View of AAVSO Observations
(get recent magnitude estimates for U Sco) {{Novae Recurrent novae Scorpius (constellation) Scorpii, U