Recent observations in the Orion Nebula suggest that gray dwarfs, objects with both stellar and planetary characteristics, could potentially form planets. A study indicates that these gray dwarfs exhibit protoplanetary disks, challenging existing classifications.
Gray dwarfs possess masses as low as 13 times that of Jupiter but are insufficiently massive to initiate nuclear fusion, thus lacking the brightness of true stars. Decades ago, the Hubble Space Telescope detected such disks within the Orion Nebula, focusing on protoplanetary disks illuminated by the ultraviolet light from the nebula's brightest stars.
Kevin Luhman, an astronomy professor at Penn State and co-author of the study, noted that stars emerge from massive clouds of gas and dust in nebulae. These clouds can span light-years and are where planets are thought to form shortly after star formation.
Observations from the James Webb Space Telescope (JWST) have identified 20 probable gray dwarfs and two possible candidates, with indications of protoplanetary disks. The smallest among them has a mass of just five times that of Jupiter. Two candidates were previously identified by Hubble, and JWST's findings suggest these are the coldest and least massive protoplanetary disks known.
These observations provide critical insights into the nature of gray dwarfs and their connection to both stars and planets. However, further observations are needed to fill gaps in understanding these objects. Additionally, JWST has discovered other unusual substellar objects in the Orion Nebula, termed JuMBOs.
A paper detailing this discovery is available on arXiv and is set to be published in The Astrophysical Journal.