Astronomers have known for decades that the powerful light emitted by massive stars can disrupt planetary disks of dust and gas that swirl around young stars, the cradles of planetary birth. However, important questions remained unanswered. How fast does this process occur and will there be enough material left to form a planet?
NASA/ESA/CSA Using the James Webb Space Telescope and the Atacama Large Millimeter Array (ALMA), astronomers are now discovering the Orion Nebula, a nursery for stars, and specifically the protoplanetary disk named d203-506. I’m researching. Although it was confined to a small area, it exploded to an abnormally large size. This makes it possible to measure material loss rates with unprecedented precision.
bernet other. We observed the protoplanetary disk d203-506 illuminated by the far-ultraviolet rays of the Orion Nebula.Image credit: Berne other., doi: 10.1126/science.adh2861.
Young, low-mass stars are often surrounded by relatively short-lived protoplanetary disks of dust and gas, which are the raw materials for planet formation.
Therefore, the formation of gas giant planets is limited by processes that remove mass from the protoplanetary disk, such as photoevaporation.
Photoevaporation occurs when the upper layers of a protoplanetary disk are heated by X-rays or ultraviolet protons, raising the temperature of the gas and ejecting it from the system.
Because most low-mass stars form in clusters that also include high-mass stars, protoplanetary disks are expected to be exposed to external radiation and experience photoevaporation due to ultraviolet radiation.
Theoretical models predict that deep ultraviolet light creates a region of photodissociation, a region where ultraviolet photons projected from nearby massive stars strongly influence the gas chemistry on the surface of the protoplanetary disk. However, it has been difficult to observe these processes directly.
Dr. Thomas Howarth of Queen Mary University of London and his colleagues investigated the effects of ultraviolet irradiation using a combination of infrared, submillimeter wave, and optical observations of the protoplanetary disk d203-506 in the Orion Nebula using the Webb and ALMA telescopes.
By modeling the kinematics and excitation of the emission lines detected within the photodissociation region, they found that d203-506 loses mass rapidly due to heating and ionization by deep ultraviolet light.
According to the research team, the rate at which this mass is lost from d203-506 indicates that gas could be removed from the disk within a million years, suppressing the ability of gas giants to form within the system. It is said that there is.
“This is a truly exceptional case study,” said Dr Howarth, co-author of the paper. paper It was published in the magazine science.
“The results are clear: this young star is losing a staggering 20 Earth masses of material per year, suggesting that Jupiter-like planets are unlikely to form in this system.” .”
“The velocities we measured are in perfect agreement with theoretical models and give us confidence in understanding how different environments shape planet formation across the universe.”
“Unlike other known cases, this young star is exposed to only one type of ultraviolet light from a nearby massive star.”
“Because there is no 'hot cocoon' created by higher-energy ultraviolet light, the planet-forming material is larger and easier to study.”
_____
Olivier Verne other. 2024. Photoevaporation flow caused by far ultraviolet rays observed in a protoplanetary disk. science 383 (6686): 988-992; doi: 10.1126/science.adh2861
Source: www.sci.news
