No, It’s Not A Supernova: New Images Help Decode Betelgeuse’s Mysterious Dimming

A new image shows six new ways to look at Betelgeuse.

The orange-red supergiant star on the shoulder of the constellation Orion had astronomers and the public hoping for a supernova.

The European Southern Observatory (ESO) “Picture of the Week,” published on Monday, provides a visual explanation for Betelgeuse’s suspicious dimming. The images show two sets of data for what was going on at this star in December 2018, February 2020, and December 2020. Respectively, these dates correlate to before, during, and after Betelgeuse dimmed. It was “a change noticeable even to the naked eye,” ESO previously stated.

Is Betelgeuse About to Go Supernova?

Betelgeuse is at the end of its life, despite being a fraction of the age of the Sun. “At roughly 10 million years old, Betelgeuse is much younger than our nearly 5-billion-year-old Sun. But while it is much younger, it is also much more massive and will burn through its materials faster and will therefore have a shorter lifespan than a star like our Sun,” according to NASA.

Along with other red supergiant stars, it will someday explode as a supernova. Its dip in luminosity called the Great Dimming Event (GDE), was significant and became an exciting prospect for those wishing to witness a supernova in the sky in their lifetimes. The star’s blast would easily be seen from Earth because Betelgeuse is only 700 light-years away.

“Talk of a possible explosion sparked intrigue around the world as Betelgeuse would be the closest supernova to ever be observed and recorded by humans,” according to NASA.

The Red Supergiant Dimmed Due to the Dust

The star dimmed by about 60 percent. But rather than being a sign of a pre-supernova phase, the dimming was due to dust. The ESO image supports existing ideas about what was going on.

The top row shows Betelgeuse’s photosphere or its surface. The bottom row highlights the presence of silicon monoxide, which the ESO image description calls “a molecule that can act as a seed to form dust grains.”

Betelgeuse ejected a cloud of dust when a cold spot formed on the star’s surface, according to ESO. The dust, which NASA says was of a quantity that would have weighed several times as much as the Moon, made the star dimmer in visible light.

But it also made the star appear brighter in the top row center image, captured by the MATISSE infrared instrument on ESO’s Very Large Telescope Interferometer. A French team of researchers used MATISSE to obtain these high-resolution images of the captivating star. The dust made Betelgeuse look brighter to MATISSE because the material glows in infrared light.

According to a study the team published on September 27 in the journal Monthly Notices of the Royal Astronomical Society, the MATISSE images support the idea of a cold spot and a dust cloud.

Even if this generation doesn’t get to witness Betelgeuse’s grand supernova, all the data may help future stargazers prepare for a sight unlike anything else.