U Scorpii
U Scorpii is one of only 10 known recurring nova
A nova is a cataclysmic nuclear explosion in a star caused by the accretion of hydrogen on to the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner...

  in our galaxy
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...

. Located near the northern edge of the constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

Scorpius, sometimes known as Scorpio, is one of the constellations of the zodiac. Its name is Latin for scorpion, and its symbol is . It lies between Libra to the west and Sagittarius to the east...

 it normally has a 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...

of 18, but reaches a magnitude of about 8 during outbursts. Outbursts have been observed in 1863, 1906, 1936, 1979, 1987, 1999, and 2010.

The most recent outburst, on 28 Jan 2010, 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 all-time fastest decline to quiescence. This eruption of U Sco 2010 is now the all-time best observed nova event with 22,000 magnitudes already accumulated. For the first time ever, we have the full spectral energy distribution on every day of an eruption, and this is being put together to measure the total energy radiated by the nova. In the year 2020±2, we can expect another U Sco eruption.

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