Accretion variability changes disk emissions around the very-low-mass star 2MASS J16053215-1933159

The innermost regions of the protoplanetary disk surrounding the very-low-mass star 2MASS J16053215-1933159 have been characterized using observations from the James Webb Space Telescope. By comparing data collected in 2022 and 2024, researchers observed significant changes in the amount of light emitted by carbon monoxide gas and other material, suggesting that this small star behaves like a scaled-down version of larger, younger stars known as T Tauri stars.

Over the two-year period, the star's accretion rate—the speed at which it pulls material from its surrounding disk—dropped by a factor of 13. This slowdown caused a reduction in the disk's carbon monoxide emission, as the gas began originating from a smaller surface area near the star.

The team analyzed the star's spectrum using the JWST's NIRSpec and MIRI instruments. They found that while hydrocarbons were previously detected, they were invisible in the newer observations, likely due to specific physical conditions in the gas that prevent near-infrared light emission.

Key findings
- The star 2MASS J16053215-1933159 shows accretion variability similar to larger T Tauri stars.
- Carbon monoxide emission flux dropped by a factor of 3 between 2022 and 2024.
- The accretion rate decreased by a factor of 13 over the same period.
- Reduced disk emission is linked to a smaller emitting area rather than changes in gas temperature.
- Hydrocarbon signatures detected previously were not present in newer observations.

Scientific study

Impact of accretion variability on the CO emission of a disk around a very-low-mass star with JWST (external link)