Betelgeuse or HIP 27989, is a bright red supergiant star in the constellation of Orion. In fact, it used to be one of the brightest objects in our night sky, so much so that you could see it with the naked eye.
Have you noticed that Orion, one of the most iconic and familiar winter constellations, looks a little... different lately? It’s half as intense as usual, so scientists are wondering if it might implode. Betelgeuse is a pulsating variable star, which means it changes its brightness in semi-regular cycles. The brightness of a star is known as magnitude. The scale of magnitude is reversed, which means the brighter the star, the smaller the magnitude. A star of magnitude 1 is brighter than a star of magnitude 2 and fainter than a star of magnitude -1.
According to an article published recently by researchers at the Villanova University of Pennsylvania (U.S.), the star has dramatically reduced its light in the last two months. Scientists say it’s about 2.5 times weaker than usual and going from the ninth brightest object in the sky to number 23.
Is it almost the end for this red star?
Before a star becomes a supernova, it loses an incredible amount of mass and ejects a voluminous cloud of dust. That dust often envelops the stars, hiding them from Earth’s telescopes before they explode. So there is the possibility that the star has already exploded (it would in a Type II supernova), as light has to travel for about 600 years from Betelgeuse until it reaches our planet.
If it explodes (or has exploded), it would become as bright as a full moon for a few months, casting its own shadow at night, before fading into nothingness, and altering the contour of the constellation of Orion forever.
Is it dangerous?
Any particle from the Betelgeuse explosion can reach the solar system in about six million years, but it would have minimal impact because the heliosphere, the space region under the influence of the sun that encompasses all the planets, would be powerful enough to deflect everything.
If it were in the middle of our solar system, the scenario would be completely different. Because it has a mass 12 times that of our Sun and burns so intensely that it dies after eight million years, it would swallow up all the planets in our system. So we’re safe from the 50-light-year 'kill zone' to receive any incoming lethal radiation from Betelgeuse. What it will be is a spectacular and scientifically interesting astronomical event.
Will we see it?
Who knows. Betelgeuse could explode like a supernova any time between now and the next 100,000 years. It is really complicated to accurately expose what is happening exactly inside the giant star. At the moment, it is time to wait and observe.
Reference: ‘The Fainting of the Nearby Red Supergiant Betelgeuse’ by researchers at Villanova University. ATel #13341; E, F. Guinan, R. J. Wasatonic (Villanova Univ.) and T. J. Calderwood (AAVSO)