Astronomers have taken the first close-up picture of a star outside our galaxy and found it to be on the verge of exploding as a supernova.
Dying Star
Perhaps unsurprisingly, it’s of one of the largest stars ever discovered — a red supergiant called WOH G64 that’s roughly 2,000 times the size of the sun. “For the first time, we have succeeded in taking a zoomed-in image of a dying star in a galaxy outside our own Milky Way,” said Keiichi Ohnaka, an astrophysicist from the Universidad Andrés Bello in Chile and lead author of a study reporting the observations published today in Astronomy & Astrophysics.
Dwarf Galaxy
WOH G64 is 160,000 light-years distant in the Large Magellanic Cloud, a dwarf galaxy that orbits the Milky Way. The LMC can only be seen from the Southern Hemisphere.
WOH G64 — which would reach the orbit of Jupiter in the solar system — has been studied by astronomers since the 1970s, earning the nickname the “behemoth star.”
The new observations using the European Southern Observatory’s Very Large Telescope Interferometer in Chile reveal a star puffing out gas and dust, apparently in its final stages of life before going supernova.
Egg-Shaped Cocoon
“We discovered an egg-shaped cocoon closely surrounding the star,” said Ohnaka. “We are excited because this may be related to the drastic ejection of material from the dying star before a supernova explosion.”
Although it was studied in 2005 and 2007 by the same scientists, close-ups of WOH G64 were impossible prior to upgrades on the VLTI. However, earlier observations proved crucial in unearthing a new insight. “We have found that the star has been experiencing a significant change in the last 10 years, providing us with a rare opportunity to witness a star’s life in real time,” said Gerd Weigelt, an astronomy professor at the Max Planck Institute for Radio Astronomy in Bonn, Germany and a co-author of the study.
Extreme Star
WOH G64 is one of the most extreme stars of its kind. As they die, red supergiant stars shed their outer layers of gas and dust, but that can take many thousands of years. Is this colossal star on the brink? The dimming suggests so, as does its unexpected egg-shaped dust cocoon.
More close ups of WOH G64 are planned, but astronomers are in a race against time because as the star becomes dimmer it will become more difficult to image.
Wishing you clear skies and wide eyes.
