Credit: Y. Nazé et al., 2002,
The Astrophysical Journal, vol 580, p. 225
A Collision of Winds
Very massive stars are so bright stellar matter is driven off the star's surface
to form a strong wind which blows out into space. These stars are often found in
binary systems, bound by gravity to another star, which often possess a strong
stellar wind of its own. In these cases the winds will collide in the space
between the two stars, forming a region of shocked, extremely hot gas. This gas
is so hot that it emits large amounts of X-rays. The Chandra X-ray Observatory has recently
taken a picture of a rather unusual massive binary system, the HD5980
system in the Small Magellanic Cloud. HD 5980 is composed of two stars in a 19
day elliptical orbit, and is unusual since one of the stars underwent a large
eruption, a transient ejection of matter in 1994. The Chandra image, shown
above, shows HD 5980 as a bright, hot source of X-rays produced by the collision
of the stellars winds; the star is surrounded by a cooler reddish X-ray nebula
that's believed to be the remains of a star in front of HD 5980 which exploded
in the distant past. Astronomers can use the X-ray emission from the shocked
winds to probe the wind and stellar properties of these rare but important class
of stars.
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Last modified December 29, 2002
