| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 22m 30.78s[1][2] |
| Declination | -17° 52′ 42.8″ |
| Apparent magnitude (V) | 7.5–19.3[2] |
| Characteristics | |
| Spectral type | ? / White Dwarf |
| Variable type | eclipsing recurrent nova (NR+E)[2] |
| Astrometry | |
| Radial velocity (Rv) | 65[3] km/s |
| Details | |
| Other designations | |
|
AAVSO 1616-17, 2MASS J16223079-1752431, BD-17 4554[3]
|
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U Scorpii (U Sco) is one of only 10[4] known recurring nova in our galaxy. Located near the northern edge of the constellation Scorpius it normally has a magnitude of 18, but reaches a magnitude of about 8 during outbursts. Outbursts have been observed in 1863, 1906, 1936, 1979, 1987, 1999, and 2010.[5][6]
The most recent outburst, on 28 Jan 2010, was predicted to occur April 2009 ± 1.0 year,[7] 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.[8] By February 6 it was dimmer than magnitude 13.[8] Between February 10-19, it was flickering around magnitude 14.[8] The eruption ended on day 64, which is the all-time fastest decline to quiescence.[8] This eruption of U Sco 2010 is now the all-time best observed nova event with 22,000 magnitudes already accumulated.[8] 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.[8] In the year 2020±2, we can expect another U Sco eruption.[8]