Using the High Acuity Wide-field K-band Imager (HAWK-I) on ESO’s Very Large Telescope (VLT), astronomers have captured a new image of the emission nebula RCW 36, highlighting the luminous cradle of newborn stars and substellar objects known as brown dwarfs.
This VLT/HAWK-I image shows the emission nebula RCW 36; while the dark clouds in the middle of the image make up the head and body of the bird of prey, the filaments extending away from the body to the left and right compose its wings; below it, is a mesmerising blue nebula with massive newly born stars, whose intense radiation make the gas around them glow brightly. Image credit: ESO / do Brito do Vale et al.
RCW 36 is located some 2,300 light-years away in the constellation of Vela.
Also known as Gum 20, the nebula is one of the sites of massive-star formation closest to our Solar System.
The object is part of a larger-scale star-forming complex known as the Vela Molecular Ridge.
RCW 36 contains a star cluster approximately 1.1 million years old.
The most massive stars in this young cluster are two O-type stars, but it also contains hundreds of lower-mass stars.
“Embedded stellar clusters are regions of active, or very recent, star formation in the Milky Way that arise in the interior of cold, dense molecular gas clouds,” said Afonso do Brito do Vale, a Ph.D. student at the Instituto de Astrofísica e Ciências do Espaço and the Laboratoire d’Astrophysique de Bordeaux, an dhis colleagues.
“In these clouds, a broad range of stellar and substellar cores formed from local gravitational instabilities eventually evolve through accretion and contraction processes to shed the gas and dust around them.”
Resembling a hawk, the RCW 36 nebula was also captured by a hawk — VLT’s HAWK-I instrument.
“While the most apparent stars in this image may be the massive and bright baby stars, we are actually more interested in hidden, very dim stars called brown dwarfs — objects unable to fuse hydrogen in their cores,” do Brito do Vale said.
“HAWK-I is perfectly suited for this task. It observes at infrared wavelengths, where these cold failed stars are more easily spotted, and it can correct atmospheric turbulence with adaptive optics, delivering sharp images like this one.”
“Besides providing invaluable data to understand how brown dwarfs form, we produced a striking image of massive stars ‘pushing’ away the clouds of gas and dust around them almost like an animal breaking through its eggshell for the first time.”
“Who knows, perhaps the cosmic hawk is guarding his baby stars — watching over them as they ‘hatch’.”
The team’s findings were published in the journal Astronomy & Astrophysics.
_____
A.R.G. do Brito do Vale et al. 2026. Substellar population of the young massive cluster RCW 36 in Vela. A&A 706, A149; doi: 10.1051/0004-6361/202557493
