Over the past thirty years, it has become clear that protoplanetary disks were forming around young stars emerging from thecollapsecollapse of cloudsclouds molecular and dusty, dense and cold, but nevertheless turbulent. Protoplanetary disks and proto-starsproto-stars open clusters that can contain hundreds of young stars are even formed in nurseries, which will then disperse in the Milky Way.
Some of the stars, which are thus born from the fragmentation of the clouds, are very massive and emit a flow of ultraviolet radiation capable of eroding the clouds and giving rise to structures, such as those of the famous pillars of the creation of the nebula of the 'Eagle.
Alma and Sigma of Orion
Until then, we thought that sometimes the breath of broadcastsbroadcasts in the ultraviolet (the lightlight carriesenergyenergy and the quantity of movementquantity of movement and can exercise pressionpression on the mattermatter) could also inhibit the formation of planets in protoplanetary disks, too close to the massive nursery stars. But, a team of researchers has just announced, in a publication that can be found in open access on arXivthat this was not always the case.
The discovery gives us additional information on the mechanisms of the formation of planetary processions. It was obtained by looking from the Atacama Large Millimeter/Submillimeter Array (Alma) towards the cluster Sigma Orioniswhich is irradiated by intense ultraviolet light from a nearby massive star.
This cluster is located close to the famous Horsehead Nebula which, with the nebulanebula of the Flame, is part of the molecular cloud ofOrionOrionone of the most active star-forming regions in the sky, containing protoplanetary disks and very young stars. Orion's molecular cloud is located between 1500 and 1600 light yearslight years from Earth and is several hundred light years wide. It of course contains the famous Orion Nebula, also called M42.
Zoom in on the heart of the Sigma Orionis cluster, the constellation of Orion with a multiple sigma star system Ori Aa,Ab,B as the video explains. © Gabriel Pérez (SMM, IAC), Sergio Simón-Díaz (IAC, ULL) and Jose A. Caballero (CAB, INTA)
Disks hollowed out by giant protoplanets in orbit
The resolutionresolution what Alma can achieve in his observations allowed the astrophysicistsastrophysicists to renew their knowledge of eight protoplanetary disks in the cluster Sigma Orionisdiscs subjected to ultraviolet radiation so intense that we did not expect to find traces ofexoplanetsexoplanets. But, as explained in a press release from National Radio Astronomy Observatory (NRAO), Alma found traces of holes and rings in most disks, structures generally associated with the formation of giant planetsgiant planets accreting gazgaz and dust, like JupiterJupiter.
Which made Jane Huang, lead author of the study, say: “ We expected that the high levels of radiation in this cluster would inhibit planet formation in the outer regions of these disks. But instead we see signs that planets could form at distances of tens ofastronomical unitsastronomical units of their stars, like what we have observed in less hostile environments. These observations suggest that the processes behind planet formation are quite robust and can operate even under difficult circumstances. This gives us more confidence that planets can form in even more places across the GalaxyGalaxyeven in regions that we previously thought were too hostile. »
The press release added: “ These results have implications for understanding the formation of our own Solar systemSolar systemwhich likely evolved in a similarly high radiation environment. They also motivate future studies of disks in even more extreme stellar neighborhoods… This study demonstrates the power of Alma to probe planet formation in diverse environments across the galaxy. As the astronomersastronomers build a more complete picture of how planets form under different conditions, they move closer to understanding the origins of Earth and prevalenceprevalence planets around other stars. »
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