Astronomers have released a new image of the outer
atmosphere of Betelgeuse – one of the nearest red supergiants to Earth –
revealing the detailed structure of the matter being thrown off the star.
The new image, taken by the e-MERLIN radio telescope array
operated from the Jodrell Bank Observatory in Cheshire, also shows regions of
surprisingly hot gas in the star’s outer atmosphere and a cooler arc of gas
weighing almost as much as the Earth.
Betelgeuse is easily visible to the unaided eye as the
bright, red star on the shoulder of Orion the Hunter. The star itself is huge –
1,000 times larger than our Sun – but at a distance of about 650 light years it
still appears as a tiny dot in the sky, so special techniques combining
telescopes in arrays are required to see details of the star and the region
around it.
The new e-MERLIN image of Betelgeuse – published in the
journal Monthly Notices of the Royal Astronomical Society, shows its atmosphere
extends out to five times the size of the visual surface of the star. It
reveals two hot spots within the outer atmosphere and a faint arc of cool gas
even farther out beyond the radio surface of the star.