Scientists from the Indian Institute of Astrophysics (IIA) have unveiled an intriguing secret behind the dusty veil of a young star named T. Chamaeleontis (T. Cha), quietly forming planets about 350 light years from Earth when part of its circumstellar inner wall collapsed partially.
According to the Department of Science and Technology, this can help rewrite our understanding of how planetary systems evolve.
T Chamaeleontisan (T. Cha) is surrounded by a planet-forming disk called circumstellar disk that contains a wide gap- likely carved out by a newborn planet.
“Normally, the dense inner regions of such disks act like a protective wall or veil blocking much of the star’s ultraviolet light from reaching the colder, outer regions. That shielding makes Poly Atomic Hrydrocarbons (PAHs), flat, honeycomb-shaped molecules (Benzene rings) made of carbon and hydrogen thought to be among the earliest precursors of life’s chemistry, especially hard to detect around low-mass, Sun-like stars,” the department said.
While these molecules are common in interstellar clouds, detecting them in the disks of low-mass, Sun-like stars has been challenging due to the low amount of ultra violet light produced by them.
The IIA scientists used archival spectroscopic data from NASA’s James Webb Space Telescope (JWST) Mid Infrared Instrument (MIRI) to study polycyclic aromatic hydrocarbons (PAHs) in the spectrum of this star.
The ultra-sensitive JWST telescope, almost by accident, caught the moment in 2022 when that veil thinned- and an ancient kind of chemistry lit up in space. The material from the disk of the star suddenly plunged onto the star in a burst of accretion, thinning or partially collapsing that inner wall. As this happened ultraviolet radiation suddenly streamed outward, illuminating parts of the disk that were once in shadow. This helped shed light on the survival and variation of complex hydrocarbon molecules in the planet-forming disk around a young, Sun-like star.
“JWST’s MIRI has now revealed them clearly in T. Cha and this is one of the lowest mass stars with PAH detection in their circumstellar disk,” said Arun Roy, a post-doctoral fellow at the IIA.
T. Cha was observed by the JWST in 2022, when the inner wall had partially collapsed allowing ultraviolet photons to flood the outer disk.
“This sudden illumination excited the PAHs in the disk, making them glow strongly in the JWST’s detectors. It was like a curtain lifting, revealing chemistry that had been hidden for years,” Mr. Roy added.
Published – January 01, 2026 10:11 pm IST
