Exploring Brown Dwarfs and Infant Stars: VLT’s Study of RCW 36

Utilizing the Highly Sensitive Wide-Field K-Band Imager (HAWK-I) on ESO’s Very Large Telescope (VLT), astronomers have captured stunning new images of the emission nebula RCW 36. These images reveal the vibrant cradles of newly formed stars and intriguing substellar entities known as brown dwarfs.



This captivating VLT/HAWK-I image of emission nebula RCW 36 features dark clouds forming the head and body of a bird of prey, with filaments extending as wings. Below, a fascinating blue nebula hosts a newly formed giant star, illuminating the surrounding gas. Image credit: ESO / de Brito de Vale et al.

Situated approximately 2,300 light-years away in the constellation Hera, RCW 36—also known as Gum 20—is one of the nearest massive star-forming regions to our solar system.

This nebula is part of the expansive star-forming complex known as the Vera Molecular Ridge.

RCW 36 houses a star cluster that dates back around 1.1 million years.

The most massive stars in this young cluster are two O-type stars, alongside several hundred lower-mass stars.

“Embedded star clusters are active sites of very recent star formation located within dense molecular gas clouds in the Milky Way,” explained Dr. Afonso de Brito de Vale, a student and researcher at the Spanish Institute of Astronomical Sciences and the Bordeaux Institute of Astrophysics.

“Within these clouds, stellar and substellar nuclei emerge from local gravitational instabilities, evolving through accretion and contraction processes that expel surrounding gas and dust.”

The hawk-like nebula RCW 36 has been vividly captured by the VLT’s HAWK-I instrument.

“While the most obvious star in this image may be a bright young star, our primary interest lies in the hidden, faint stars known as brown dwarfs—objects that cannot undergo hydrogen fusion in their cores,” Dr. de Brito de Vale noted.

“HAWK-I is perfectly designed for this task, as it operates in infrared wavelengths, where these cold, failed stars are more easily detectable and can correct for atmospheric turbulence using adaptive optics, resulting in exceptionally sharp images.”

“Beyond providing essential data on the formation of brown dwarfs, we have captured a stunning image of a massive star seemingly ‘pushing aside’ clouds of gas and dust, reminiscent of an animal breaking free from an egg.”

“Perhaps a space hawk is watching over the baby star as it ‘hatches’.”

The team’s findings have been published in the journal Astronomy and Astrophysics.

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ARG de Brito de Vale et al. 2026. A substar group of Vera’s young massive star cluster RCW 36. A&A 706, A149; doi: 10.1051/0004-6361/202557493

Source: www.sci.news

VLT’s Attention Shifts to Near Earth Asteroid 2024 YR4

The near-Earth asteroid called the 2024 YR4 has been closely monitored over the past few months as its chances of impacting Earth increased to about 3% in 2032. After the latest observations from the ESO's very large telescope (VLT), the probability of impact has decreased to about 0.001%.

This VLT image shows asteroid 2024 YR4 near Earth. Image credit: ESO/O. hainaut.

2024 yr4 On December 27, 2024, the Asteroid Terrestrial Impact of Río Hurtado was discovered by the Last Alert System (Atlas) station.

Between 40-90 m in diameter, the asteroid took a close approach to Earth at a distance of 828,800 km (515,000 miles) two days before its discovery.

The 2024 YR4 is currently moving, with the next close approach taking place on December 17th, 2028.

On December 22, 2032, the asteroid quickly rose to the top of the ESA risk list due to its size and potential impact. This is a catalogue of all the space rocks that can affect Earth.

“Uncertainty means that the orbit of an asteroid is like a flashlight beam. It becomes wide and wide and ambiguous in the distance.”

“As we observe more, the beam becomes sharper and narrower. The Earth was illuminated more by this beam. The probability of impact increased.”

The observations of the new VLT, along with data from other observatory data, were able to exclude the impact on Earth in 2032 by Dr. Hainaut and his colleagues, but were able to constrain sufficient orbits for all.

“The narrower beams are now far from Earth,” Dr. Heinout said.

The impact probability reported by the ESA's short-range object adjustment center is about 0.001%, and asteroids no longer place the ESA risk list above.

As the 2024 YR4 is far from Earth, it has become increasingly faint and difficult to observe it with all but the largest telescopes.

“The VLT contributes to the observation of this asteroid due to its mirror size and excellent sensitivity, and is an excellent darker sky at the Delusional Observatory of ESO in Chile, where the telescope is located,” the astronomer said.

“This would ideally help track faint objects such as the 2024 YR4 and other potentially dangerous asteroids.”

“Unfortunately, the same pristine, dark sky that allowed these important measurements is now under threat by Industrial Megaproject Inna by AES Andes, a subsidiary of US utility AES Corporation.”

“The project plans to cover areas similar to the size of small cities and be located at the nearest point, about 11 km from VLT.”

“Because of its size and proximity, INNA will have a devastating effect on the quality of Paranal's sky, particularly due to mild contamination from industrial facilities.”

“In bright sky, telescopes like VLT lose the ability to detect the weakest universe's targets.”

Source: www.sci.news