This galactic gas bubble has a large surprise. How large? At least
8 times the mass of the Sun. Nestled in the shell around this large
bubble is an embryonic star that looks set to turn into one of the
brightest stars in the Galaxy.
The Galactic bubble is known as RCW 120. It lies about 4300
light-years away and has been formed by a star at its centre. The star
is not visible at these infrared wavelengths but pushes on the
surrounding dust and gas with nothing more than the power of its
starlight. In the 2.5 million years the star has existed. It has raised
the density of matter in the bubble wall so much that the quantity
trapped there can now collapse to form new stars.
Herschel is the largest astronomical telescope ever to be placed into
space. The diameter of its main mirror is four times larger than any
previous infrared space telescope and one and a half times larger than
Hubble. As stars begin to form, the surrounding dust and gas is warmed
up to a few tens of degrees above absolute zero and starts to emit at
far-infrared wavelengths. The Earth's atmosphere completely ...