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

recurrent 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 ...

system, one of 10 known recurring novae in the

Milky Way galaxy The Milky Way or Milky Way Galaxy is the galaxy that includes the 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 in other arms of the galaxy, which are ...

. 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 first constellati ...

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 whose recognition pred ...

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 a recurring nova. This eruption of U Sco became the best-observed nova event to its day, with 22,000 magnitudes accumulated. Astronomers then predicted that another eruption of U Sco would 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 as a nova in 1863 by English astronomer N.R. Pogson, U Scorpii was the third nova to be identified as recurrent, by American astronomer and historian of science Helen L. Thomas, in the years preceding

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

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) {{Stars of Scorpius Recurrent novae Scorpius Scorpii, U