Astronomers obtain sharpest image of the most massive star ever discovered

A team of astronomers using the International Gemini Observatory (IGO) has made a significant breakthrough by obtaining the sharpest image of the most massive star discovered to date. Lying 1,60,000 light-years from Earth, this star named R136a1 is nestled in the center of the Tarantula Nebula in the Large Magellanic Cloud, a dwarf companion galaxy of the Milky Way.

Published in The Astrophysical Journal, the new findings, according to the scientists, would improve their understanding of the formation of stars 100 times the mass of the sun. They haven’t been able to solve the puzzle around their birth because these behemoths are not easy to photograph. The reason is that they reside in dense clouds of star clusters and ‘die’ relatively sooner. 

More about the breakthrough discovery

The discovery was made using the Zorro instrument on the Chile-based Gemini South telescope of the IGO which is operated by the National Science Foundation’s NOIRLab. While the star R136a1 is considered to be the most massive one ever found, Venu M. Kalari, the lead researcher from NOIRLab, says that these stars might not be as massive as previously thought. 

This was proved through their recent observations which revealed that this newly imaged star is between 170 to 230 times the mass of the sun as opposed to previous estimates of between 250 to 320 times. However, this significant reduction in the number still makes it the most massive star to date. 

(View of the star R136a1, Hubble vs Gemini; Image: International Gemini Observatory/NOIRLab/NSF/AURA)

“Our results show us that the most massive star we currently know is not as massive as we had previously thought," explained Kalari as per a report by the Association of Universities for Research in Astronomy (AURA). "This suggests that the upper limit on stellar masses may also be smaller than previously thought”. 

Notably, the cluster this massive star resides in has been previously observed using the Hubble Space Telescope, however, it failed to produce an image as clear as the Gemini telescope. To obtain the new photograph, astronomers used a new technique called ‘speckle imaging’ which enables the telescopes to overcome the blurring effect due to the Earth’s atmosphere. 

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