TAIPEI, Taiwan, Nov. 25 (UPI) -- VY Canis Majoris is one of the largest stars in the Milky Way, but it won't be for long.
The stellar behemoth, a red hypergiant located 3,900 light-years from Earth, is quickly shedding mass, and now new observations are helping astronomers better understand how and why.
VY Canis Majoris is dying. As it does so, it is constantly losing large amounts of dust and gas as it expands and expels mass. Eventually, the hypergiant will explode in a violent supernova, collapsing on itself and destroying much of the surrounding cloud of stellar material. The rest is sent out to into interstellar space where it will go on to form new stars and planets.
Astronomers' latest observations confirm the role radiation pressure plays in pushing out the star's gas and dust into the surrounding cloud as it expands.
Scientists have long assumed radiation pressure to be responsible for mass expulsion, but being a relatively weak force, scientists estimated expelled stellar particles would need to be rather large to be affected.
The latest observations, made using the SPHERE instrument on the European Southern Observatory's Very Large Telescope, prove scientists estimated correctly -- the gas and dust particles expelled by the hypergiant are 0.5 micrometers across, 50 times bigger than most interstellar particles.
The findings were shared in a new paper, published in the journal Astronomy & Astrophysics.
Currently, VY Canis Majoris is 30 to 40 times more massive than the sun and 300,000 times as luminous, but its impressive size won't last.
"Massive stars live short lives," lead study author Peter Scicluna, an astronomer with the Academia Sinica Institute for Astronomy and Astrophysics in Taiwan, said in a press release. "When they near their final days, they lose a lot of mass. In the past, we could only theorize about how this happened."
"But now, with the new SPHERE data, we have found large grains of dust around this hypergiant," Scicluna added. "These are big enough to be pushed away by the star's intense radiation pressure, which explains the star's rapid mass loss."