A Tour of V745 SCO

Narrator (April Hobart, CXC): For decades, astronomers have known about irregular outbursts from the double star system V745 Sco, which is located about 25,000 light years from Earth. Astronomers were caught by surprise when previous outbursts from this system were seen in 1937 and 1989. When the system erupted on February 6, 2014, however, scientists were ready to observe the event with a suite of telescopes including NASA’s Chandra X-ray Observatory.

V745 Sco is a binary star system that consists of a red giant star and a white dwarf locked together by gravity. These two stellar objects orbit so closely around one another that the outer layers of the red giant are pulled away by the intense gravitational force of the white dwarf. This material gradually falls onto the surface of the white dwarf. Over time, enough material may accumulate on the white dwarf to trigger a colossal thermonuclear explosion, causing a dramatic brightening of the binary called a nova.

Astronomers observed V745 Sco with Chandra a little over two weeks after the 2014 outburst. The X-ray data enabled a team of researchers to construct a three-dimensional model of an explosion from V745 Sco for the first time. This 3D model helps decipher some of the details of this system, including the presence of a disk of gas around the orbiting stars and how the blast wave moves out into space. The astronomers were also able to determine that V745 Sco is releasing a tremendous amount of energy during one of these outbursts, equivalent to about 10 million trillion hydrogen bombs.

Researchers plan on more observations of V745 Sco and others like it to learn more about how these exciting objects evolve.