VLT Discovers Third Gas Cloud near Milky Way’s Central Black Hole

The newly identified gas cloud, dubbed G2t, follows almost the same orbit as two known clouds, suggesting they were all kicked out by a pair of massive stars near the heart of our Milky Way.

This VLT image shows the stars and gas surrounding Sagittarius A*, a supermassive black hole at the center of the Milky Way. Image credit: ESO / D. Ribeiro, MPE GC team.

“This is an extremely dynamic environment, with stars and gas clouds rushing past the black hole at spectacular speeds,” said Dr. Stefan Gillessen of the Max Planck Institute for Extraterrestrial Physics and his colleagues.

“Two gas clouds, G1 and G2, were already known, but their nature and origin were still debated. »

“In particular, it was not clear whether these clouds were hiding a star inside or whether they were only made of gas.”

“However, the discovery of a third gas cloud, named G2t, now allows us to answer these questions.”

G2t was discovered using the Enhanced Resolution Imager and Spectrograph (ERIS) instrument on ESO’s Very Large Telescope (VLT).

“Thanks to the VLT, we were able to measure the 3D orbits of the clouds around the black hole,” the astronomers explained.

“The clouds are moving in a very small region in the center of this wide-field image.”

“It was revealed that G1, G2 and G2t are actually in almost identical orbits, with only a slight rotation relative to each other.”

“This rules out the possibility that each cloud hides a star at its core, because the chances of different stars having nearly identical orbits are slim.”

“The similarity of the orbits suggests that the three clouds likely share the same origin, most likely IRS16SW, a pair of massive stars expelling a huge amount of gas.”

“As IRS16SW moves around the black hole, each gas cloud is ejected into a slightly different orbit, explaining the small differences in the ‘G-triplet’ trajectories.”

“This discovery shows that, despite decades of monitoring our center of the Milky Way, new, unanswered curiosities still arise,” they said.

“But what’s more exciting than mysteries waiting to be solved?”

The discovery is described in an article in the journal Astronomy and astrophysics.

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S.Gillessen and others. 2026. The G1-2-3 gas streamer at the Galactic center. A&A 707, A79; doi: 10.1051/0004-6361/202555808