Betelgeuse, Betelgeuse, Betelgeuse!
This image from The European Space Agency’s (ESA) Herschel Space Observatory reveals multiple arcs around Betelgeuse, the nearest red supergiant star to Earth. The star, and its arc-shaped shields, could collide with an intriguing dusty ‘wall’ in about 5000 years. Betelgeuse, in the constellation Orion the Hunter, can easily be seen with the naked eye in the northern hemisphere winter night sky as the orange–red star above and to the left of Orion’s famous three-star belt.
Betelgeuse, also known as Alpha Orionis, is roughly 1,000 times the diameter of our Sun, and shines 100, 000 times more brightly. However, before us humans begin to feel ‘star-envy’ we should understand that Betelgeuse, having already swelled into a red super-giant and having shed a significant fraction of its outer layers, is likely on its way to one hellava supernova explosion! This far-infrared view from Herschel shows how the star’s winds are crashing against the surrounding interstellar medium, creating a bow shock as the star moves through space at speeds of around 30 km/s. To state in human terms — Betelgeuse is having a hissy-fit, a huge hissy-fit!
Being about 640 light-years away, Betelgeuse isn’t exactly in our stellar backyard but it is among the nearest stars to our Sun doomed to go the supernova route. When it will explode is really anyone’s guess. Given that it takes six centuries for its light to reach us, it might already have done so. The best estimate scientists give is that it will likely blow apart sometime in the next 100,000 years – a blink of the eye by cosmic standards. When it does happen Betelgeuse will erupt as a so-called Type II supernova. As its outer layers head spaceward at about five percent of the speed of light, its spent core will rapidly implode to become, most likely, a neutron star some 20 kilometers across. A neutron star, which is effectively a solid ball of nuclear matter, is so dense that a thimbleful (a thimbleful!) of its contents would outweigh the entire human population. Yes, even despite our addiction to, and indulgence in, junk food.
From the Earth, the exploding Betelgeuse will get nearly as bright as the full Moon and be visible for two or three months even in daylight. Type II supernovae pose no threat to planets that are hundreds of light-years away because their deadly radiation spreads out equally in all directions and eventually becomes too thin to be of concern. From our safe vantage-point, this will be one awesome show!