The first close-up photograph of a star in another galaxy recently made headlines, focusing on a star that is more than 160,000 light-years away from Earth.
This red supergiant star, known as WOH G64, is located in the Milky Way’s orbiting dwarf galaxy, the Large Magellanic Cloud. With a radius of almost 2,000 times that of the Sun, it has been referred to as “The Monster” or “The Behemoth” for a number of years.
It was the perfect subject for a portrait taken with the European Southern Observatory’s Very Large Telescope Interferometer because of its enormous size. It’s large enough for us to zoom in and view previously unseen intricacies.
At Chile’s Andrés Bello National University, astrophysicist Keiichi Ohnaka said, “We found an egg-shaped cocoon closely surrounding the star.” “We are excited because this may be related to the drastic ejection of material from the dying star before a supernova explosion.”
It’s challenging enough to image stars in the Milky Way. A prime example is the red giant star Betelgeuse, which is less than 650 light-years away and has a radius 764 times that of the Sun, but our views of it are so blurry that scientists are still attempting to understand why its light varies so much.
Betelgeuse is about three times as big as WOH G64, although it is 250 times farther away. As a result, it looks to us to be considerably smaller and fainter than Betelgeuse, one of the brightest stars in the sky. Despite years of studying the Behemoth, Ohnaka and his colleagues had to wait for the development of powerful enough technology to capture a detailed portrait of the creature.
This technology is in the form of a device called GRAVITY, which is intended to observe extremely small and dim objects. WOH G64 definitely fits the description of small and dim given how far away it is. After making their observations in December 2020, the researchers had to laboriously clean up, process, and rebuild the data in order to reach their goal.
Therefore, even though the image appears blurry, the amount of detail the researchers were able to capture is astounding.
According to observations made in 2005 and 2007, there is dust all around WOH G64. This is thrilling since the star is in its red supergiant phase. Massive stars that were formerly between 8 and 35 times as massive as the Sun are nearing the end of their lives. The star becomes unstable, burns intensely hot, and swells to enormous proportions before exploding in a supernova as its nuclear fuel runs out to fuse in its core.
WOH G64 is at an extremely unstable stage of its life, experiencing violent mass loss as it approaches the end, according to the dusty material.
According to the latest data, the star has actually become fainter.
Astronomer Gerd Weigelt of the Max Planck Institute for Radio Astronomy in Germany says, “We have discovered that the star has been going through a major transition in the past ten years, giving us a unique chance to observe a star’s life in real time.”
The scientists believe that the star’s fading could be due to the mass loss it has been experiencing. The star appears fainter to our telescopes because some of its light is blocked by the gas and dust it exhales.
The scientists were surprised by the ejecta bubble’s ovoid, egg-like shape. According to their modeling, which was based on earlier data, the form ought to be different. Although the exact reason for its shape is unknown, there are a few possible reasons.
It might have to do with how the material is expelled, how it travels through the surrounding space, or even whether an as-yet-unseen binary companion is present and is influencing the outflows in a way that scientists have not yet identified.
The Behemoth is an interesting and somewhat unexplored area. Since a red supergiant’s mass loss stage lasts for several thousand years, the star is indeed on the verge of going extinct. It might provide us with previously unobserved information about how big stars die.
Jacco van Loon, an astronomer and the director of the UK’s Keele Observatory, says, “This star is one of the most extreme of its kind, and any drastic change may bring it closer to an explosive end.”
The research has been published in Astronomy & Astrophysics.