* Astronomy

Blobrana · L

RE: U Scorpii

Blobrana · L

Astronomers from Sheffield and Southampton Universities and Winchester College have identified a star that will light up the night sky with a massive explosion. The star, known as U Scorpii will explode within the next 700,000 years - a blink of an eye in astronomical terms. These Type Ia supernovae, as they are known, may hold the key to the fate of the Universe itself.
U Scorpii is a type of binary star system called a recurrent nova. It is made up of a sub-giant star (what our Sun will become when it swells up near the end of its life in a few billion years) and a compact, dense star made of carbon and oxygen known as a white dwarf. The sub-giant whirls around the white dwarf, completing an orbit in just over a day. All the time, matter is being sucked from the sub-giant onto the white dwarf via a hot swirling disc. Every 10 years, U Scorpii undergoes a nova explosion, where matter on the surface of the white dwarf is ignited and burns in a thermonuclear runaway explosion, making it flare up. This has the affect of releasing some of the accreted mass into space, but much of it remains allowing the white dwarf to grow with time.

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Blobrana · L

Novae explode without warning, and even recurrent novae are pretty unpredictable. (For instance, we've been waiting way too long for T Pyxidis to erupt again
But here's a prediction about a recurrent nova that should go off in a specific year: 2009. I've calculated that the recurrent nova U Scorpii, north of Antares and east of the head of Scorpius, should explode any month now. My "crystal ball" is based on old archival photographs and data from amateur astronomers. This brings a golden opportunity for amateurs and professionals to catch the early hours of a nova eruption and to prepare in advance for an intensive observing campaign.

Source

U Scorpii last erupted on the 25th February 1999. The reccurrent nova outburst was discovered by Patrick Schmeer (Germany) at visual magnitude 9.5, and afterwards rose briefly to reach magnitude 8.
The brightening of U Scorpii occurred very rapidly - brightening by at least 5 magnitudes in less than four hours. In quiescence it is around magnitude 17.6.
The last recorded eruptions (1863, 1936, 1945, 1969, 1979, 1987, 1999) indicates the eruption cycle is roughly once every 10 ± 2 years.
Based on these past outbursts the prediction is for an eruption in April 2009 ± 1.0 year.
The last few eruptions were all discovered by amateur astronomers.

Position(2000): RA 16 22 30.68, Dec -17 52 42.1