January 22, 2013
Nearby Red Supergiant Possibly Headed For A Collision In 5,000 Years
Lee Rannals for redOrbit.com - Your Universe Online
A new image released by the European Space Agency (ESA) shows multiple arcs around Betelgeuse, the nearest red supergiant star to Earth.Betelgeuse and its arc-shaped shields could be colliding with a dusty "wall" in the next 5,000 years, according to ESA.
The red supergiant star sits at the constellation Orion the Hunter, and can easily be seen with the naked eye in the northern hemisphere winter night sky as an orange-red star to the left of Orion's three-star belt.
Betelgeuse is about 1,000 times the diameter of our Sun, and shines about 100,000 times more brightly. The star is likely on its way to a supernova explosion, having already swelled up into a red supergiant, and shedding significant fraction of its outer layers.
A view from ESA's Herschel Space Observatory gives a far-infrared look at how the star's winds are crashing against the surrounding interstellar medium. This creates a bow shock as the star moves through space at about 18 miles per second.
The dusty arcs ahead of the star's direction of motion show off a turbulent history of mass loss, according to ESA.
Closer to the star, an inner envelope of material features a pronounced asymmetric structure. Large convective cells in the star's outer atmosphere have resulted in localized, clumpy ejections of dusty debris at different stages.
A linear structure is also seen further away from the star, past the dusty arcs. While earlier theories suggests this bar resulted from material being ejected during a previous stage of star evolution, the new image suggests it is either a linear filament linked to the galaxy's magnetic field, or the edge of a nearby interstellar cloud.
If the bar is a completely separate object, then the motion of Betelgeuse and its arcs, and the separation between them, suggests the outermost arc will collide with the bar in just 5,000 years, with the red supergiant hitting the bar about 12,500 years later.
A study entitled “The enigmatic nature of the circumstellar envelope and bow shock surrounding Betelgeuse as revealed by Herschel" was published in Astronomy & Astrophysics in December last year.