The most massive known star in the universe just got its best close-up, revealing the star could be smaller than astronomers previously thought.
Astronomers using the Gemini South telescope in Chile photographed the star R136a1located about 160,000 light years from Earth in the center of the tarantula nebula in the Large Magellanic Cloud — a dwarf companion galaxy to the Milky Way. His observations show that the giant star (and others like it) may not be as massive as previously thought.
“Astronomers have yet to fully understand how the most massive stars, those with more than 100 times the mass of the sun, form,” according to a declaration (opens in a new tab) of the NOIRLab of the National Science Foundation (NSF), which operates the Gemini South telescope. “A particularly challenging piece of this puzzle is getting observations of these giants, which typically inhabit the densely packed hearts of dust-shrouded star clusters.”
Related: What is the most massive star?
Gemini South’s Zorro instrument uses a technique known as speckle imaging, which combines thousands of short-exposure images of stars deep in the universe to cancel the blur effect of earth’s atmosphere. This technique allowed astronomers to more precisely separate the brightness of R136a1 from its nearby stellar companions, resulting in the sharpest image of the giant star ever acquired.
While previous observations suggested that R136a1 was between 250 and 320 times more massive than the Sunthe new Zorro observations show that the giant star’s mass may be closer to 170 to 230 times that of the sun, still qualifying it as the most massive star known.
“Our results show us that the most massive star currently known to us is not as massive as we had previously thought,” Venu M. Kalari, the study’s lead author and NSF NOIRLab astronomer, said in the statement. “This suggests that the upper limit of stellar masses may also be smaller than previously thought.”
A star shine and the temperature is based on its mass. In other words, more massive stars appear brighter and hotter. The astronomers estimated the mass of R136a1 by comparing its observed brightness and temperature with theoretical predictions. Since the new images of Zorro more accurately separated the brightness of R136a1 from its nearby stellar companions, astronomers were able to estimate that the star has a lower brightness and, in turn, a lower mass than previous measurements showed. , according to the statement.
Massive stars like R136a1 grow rapidly, burning through their fuel reserves in just a few million years before dying in flames in supernova explosions, which sow galaxies with heavy elements responsible for the formation of new stars and planets. This is the fate of most stars that are more than 150 times the mass of the sun. However, if stellar masses are smaller than previously thought, then supernovae may also be rarer than expected, the researchers noted.
the study has been accepted for publication (opens in a new tab) in The Astrophysical Journal.
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