Flares Spotted On Red Giant, Mira

The telescope Alma has spotted a massive flare on the red giant, Mira. This activity is similar to the flares we observe on our own Sun and could well help astronomers establish how winds around giant stars shape our galaxy’s ecosystem.

Alma telescope

Alma telescope facility at 5000 metres altitude in the Andes

Two stars

Mira is a double star (Mira A and Mira B) and the new findings from the telescope have revealed details of the Mira A surface for the first time.

The study is being undertaken by the Chalmers University of Technology. A lead astronomer, Wouter Vlemmings, said: “Alma’s vision is so sharp that we can begin to see details on the surface of the star. Part of the stellar surface is not just extremely bright, it also varies in brightness. This must be a giant flare, and we think it’s related to a flare which X-ray telescopes observed some years ago”,

Red giants

Mira A and red giants like it are a very important part of the ecosystem that exists in our galaxy. When these stars get towards their end, they have uneven smoky winds that peal off the outer layers. Winds like this are made up of heavy elements which are pushed into space to places where they can create planets and stars. The majority of the nitrogen and carbon in our bodies is thought to have come from stars and to have been spread by the winds that exist around them.

Mira A flare

Artists impression of a flare on Mira A

Very active

The Latin for Wonderful is the word Mira, and it has been viewed for a few hundred years and recogonised as one of the more volatile stars. You can even see the star without equipment when it is shining at its brightest. Mira exists in the constellation of Cetus 420 light years away. It sits in a binary system with one of the Mira stars being a large, cool, red giant and the other a hot white dwarf. The mass of each star is about the same as the sun and they orbit each other from about the same distance as Pluto from the Sun.

Auroras

We experience solar storms that are created by magnetic fields on our Sun and these often create auroras like the Northern Lights on Earth. The flares on Mira A suggest that similar magnetic fields exist and interestingly the distance between Mira A and Mira B means they are close enough for gas and other materials to be transferred from one star to the other.