Unveiling the Destructive Power of Ultraviolet “Winds” with the James Webb Space Telescope

2024-03-11 12:35:28

Research with the James Webb Space Telescope has provided the first direct evidence that ultraviolet “winds” from nearby massive stars can cause rapid mass loss in the protostellar disks of young stars through FUV-driven photoevaporation. (The artist’s concept.) Credit: twoday.co.il.com

Research using the James Webb Space Telescope highlights the destructive power of ultraviolet “winds” on the gas in protoplanetary disks surrounding young stars, shedding light on the complex dynamics that limit the formation of gas giants in the cosmos.

Ultraviolet “winds” from nearby massive stars strip the gas from the protoplanetary disk of a young star, causing it to rapidly lose mass, according to new research. He reports the first directly observed evidence of far-ultraviolet (FUV)-driven photoevaporation of a protoplanetary disk. The findings, using observations from the James Space Telescope (JWST), provide new insights into the constraints on the formation of gas giant planets, including in our own solar system.

Insights into the formation of the gas giant planets

Young, low-mass stars are often surrounded by relatively short protoplanetary disks of dust and gas, which provide the raw materials from which planets form. As such, gas giant planet formation is limited by processes that remove mass from protoplanetary disks, such as photoevaporation. Photoevaporation occurs when the upper layers of protoplanetary disks are heated by protons in X-rays or ultraviolet rays, increasing the temperature of the gas and causing it to escape from the system. Since most low-mass stars form in clusters that also contain massive stars, protoplanetary disks are expected to be exposed to external radiation and experience UV-driven photoevaporation.

The inner region of the Orion Nebula as seen by the James Webb Space Telescope’s NIRCam instrument. Credit: NASA, ESA, CSA, Data reduction and analysis: PDRs4All ERS team; Graphic processing S. Fuenmayor

Observational evidence from JWST and ALMA

Theoretical models predict that far-ultraviolet radiation produces photodissociation regions (PDRs)—regions where ultraviolet photons emitted by nearby massive stars strongly influence the chemistry of gases on the surface of protoplanetary disks. However, direct observation of these processes has been elusive.

Using near-infrared and submillimeter measurements from JWST and the Atacama Large Millimeter Array (ALMA), respectively, Olivier Barna and colleagues report observations of a FUV-irradiated protoplanetary disk, d203-506, located within the Orion Nebula. By modeling the kinematics and excitation of the emission lines detected within the PDR, the researchers found that d203-506 is losing mass at a high rate due to FUV-driven heating and ionization.

According to the findings, this rate of mass loss from d203-506 suggests that the gas could be removed from the disk within a million years, thus suppressing the ability of gas giants to form within the system. “Dynamic and compositional studies of the Solar System indicate that it formed in a star cluster that contained one or more massive stars, so it may have been affected by FUV radiation,” Brenna. et al. to write.

For more information on this discovery:

• The Webb Space Telescope reveals the unseen forces that shape planetary systems