The most massive known star in the universe captured with unprecedented clarity

To put it simply, the most massive known star in the universe is less massive than scientists once believed. But even docked at a few levels, this stunning ball of gas remains the most massive known star in the universe. It’s so huge.

Affectionately named R136a1, the luminous giant lives 160,000 light-years from Earth at the center of an amazing, stringy star factory known as the Tarantula Nebula. Last week, astronomers announced that celestial observations collected with the Gemini South telescope in Chile had produced the sharpest image of it ever taken, revealing its true weight.

For years, data suggested that this star had a mass between 250 and 350 times that of the sun. But according to the team’s study, which is due to appear in The Astrophysical Journal, the new view indicates that it is more like 170 to 230 times the mass of our host star.

Nevertheless, the R136a1 is a gleaming monster.

“Even with this lower estimate, R136a1 still qualifies as the most massive star known,” the research team said in a press release.

For context, the Earth has a mass of approximately (don’t think about that number, just feel it) 6,000,000,000,000,000,000,000,000 kilograms. The mass of Jupiter is even 318 times this. All of this is just two worlds in our cosmic neighborhood. And yet the sun represents 99.8% of the mass of the entire solar system. If that hurts your brain, another way to think about the size discrepancy is that a million Earths could fit inside the sun.

So here is. R136a1 is between 170 and 230 times more massive than the Sun. Do with this information what you want.

A hyperrealistic illustration of R136a1, which appears as a bluish-white patch of light in the center.  It is drawn much larger than all the other colored dots of light around it.

Artist’s rendering of R136a1, the largest known star in the universe, which resides inside the Tarantula Nebula in the Large Magellanic Cloud. Perhaps one day we will have a clear enough picture of this stellar body to rival even this portrait.

NOIRLab/NSF/AURA/J. da Silva/space engine

For the purposes of scientific progress, “this suggests that the upper limit of stellar masses may also be smaller than previously thought,” said Venu M. Kalari, an astronomer at the National Science Foundation’s NOIRLab and lead author of the study. ‘article. .

Additionally, Kalari’s results could implicate our understanding of certain elements of the universe, particularly those created from the explosive death of stars larger than 150 solar masses – those that have been the most violent.

OK, but why didn’t we know before?

Basically, the most spectacular, hottest, and gigantic stars in the universe are also usually the shortest, most distant, and most mysterious.

First, truly massive stellar bodies tend to exist inside densely populated star clusters that are hidden by residual stardust, such as R136a1 resides in the Tarantula Nebula. This makes it quite difficult for ground-based equipment to discern the precise qualities of a colossal star of interest – other stars somehow interfere with observations.

On the right is a super blurry version of the star cluster that contains R136a1.  The star at hand almost merges with the one right next to it.  To the left is the new image we have of the region -- it's much, much clearer.

This image shows how the sharpness and clarity of the Zorro imager on the 8.1-meter Gemini South Telescope in Chile (left) compares to an earlier image of R136a1 taken with the NASA/ESA Hubble Space Telescope ( to the right).

Gemini International Observatory/NOIRLab/NSF/AURA Acknowledgments: Image processing: TA Rector (University of Alaska Anchorage/NSF’s NOIRLab), M. Zamani (NSF’s NOIRLab) & D. de Martin (NSF’s NOIRLab); NASA/ESA Hubble Space Telescope

“Giant stars also live fast and die young,” according to NOIRLab, an organization that operates the Gemini South Telescope, “depleting their fuel reserves in just a few million years. By comparison, our sun is less than half of its billion-year lifespan.” Aka, there’s a bit of a time limit on the already daunting task of identifying supermassive stars in a dust-shrouded star cluster.

This is where the Gemini South telescope comes in.

To image R136a1 with unprecedented clarity, this machine used a special instrument called Zorro to circumvent some (giant) obstacles to stargazing. Zorro used a technique known as speckle imaging, which helped the telescope overcome the blurring effect caused by Earth’s atmosphere. Atmospheric blur poses such a big obstacle to telescope observations that, in fact, it was the reason NASA launched the Hubble Space Telescope in 1990. The goal back then was to get a lens above our planet’s atmosphere for beautiful, clear cosmic images.

Still on the ground, however, Zorro got around the atmospheric blur problem in a different way. Essentially, it took thousands of short-exposure R136a1 images, which were then digitally processed by the study team.

“Under the right conditions, an 8.1-meter telescope pushed to its limits can rival not only the Hubble Space Telescope in terms of angular resolution, but also the James Webb Space Telescope,” said Ricardo Salinas, co-author of the article and the instrument. Zorro’s scientist, said in the statement. “This observation pushes the boundaries of what is considered possible using speckle imaging.”

The eventual conglomeration of images was sharp enough to allow the team to separate the luminosity of R136a1 from the luminescence emitted by nearby stellar companions, leading to a lower estimate of its luminosity, and therefore its mass. “Astronomers are able to estimate the mass of a star by comparing its observed luminosity and temperature with theoretical predictions,” according to NOIRLab.

“We started this work as an exploratory observation to see how well Zorro could observe this type of object,” Kalari said. “Although we urge caution when interpreting our results, our observations indicate that the most massive stars may not be as massive as previously thought.”

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