This orange blob shows the nearby star Betelgeuse, as seen by the Atacama Large Millimeter/submillimeter Array
(ALMA). This is the first time that ALMA has ever observed the surface
of a star and this first attempt has resulted in the highest-resolution
image of Betelgeuse available.
Betelgeuse is one of the largest stars currently known — with a radius around 1400 times larger than the Sun’s in the millimeter continuum. About 600 light-years away in the constellation of Orion (The Hunter), the red supergiant
burns brightly, causing it to have only a short life expectancy. The
star is just about eight million years old, but is already on the verge
of becoming a supernova. When that happens, the resulting explosion will
be visible from Earth, even in broad daylight.
The star has been observed in many other wavelengths, particularly in the visible, infrared, and ultraviolet. Using ESO’s Very Large Telescope
astronomers discovered a vast plume of gas almost as large as our Solar
System. Astronomers have also found a gigantic bubble that boils away
on Betelgeuse’s surface. These features help to explain how the star is
shedding gas and dust at tremendous rates (eso0927, eso1121). In this picture, ALMA observes the hot gas of the lower chromosphere
of Betelgeuse at sub-millimeter wavelengths — where localised increased
temperatures explain why it is not symmetric. Scientifically, ALMA can
help us to understand the extended atmospheres of these hot, blazing
stars.
Links
Source: ESO/Potw
