Using JWST, astronomers have caught six ‘rogue’, planet-sized objects, zooming untethered to any star, wild and free through interstellar space, in the gorgeous environment of a star-forming nebula in the constellation of Perseus.
“We are probing the very limits of the star forming process,” says astrophysicist Adam Langeveld of Johns Hopkins University.
“If you have an object that looks like a young Jupiter, is it possible that it could have become a star under the right conditions?
At least some planets are thought to form from a bottom-up process, from the material left behind in the disk when the star finishes forming.
“We used Webb’s unprecedented sensitivity at infrared wavelengths to search for the faintest members of a young star cluster, seeking to address a fundamental question in astronomy: How light an object can form like a star?”
Astronomers estimate that there could be billions of rogue planets, drifting through the Milky Way.
But it’s possible that some rogue planets start their development in the same way as stars do.
So when JWST spotted six objects between five and ten times the mass of Jupiter, Langeveld and his team thought they must have formed from gravitational collapse.
Interestingly, although JWST is sensitive enough to detect even smaller objects, the researchers found no rogue worlds smaller than five Jupiters.
And the discovery of these worlds suggests fascinating possibilities, blurring the line between a star and its planets, and a planet and its moons.
As the naturally constrained offspring of host stars, planets are conceptualized.
But space is a peculiar and erratic entity; things don’t always behave according to our expectations.
Six “rogue” planet-sized objects have been observed by astronomers using JWST, zooming wild and free through interstellar space, untethered to any star, in the stunning surroundings of a star-forming nebula in the Perseus constellation.
Astrophysicist Adam Langeveld of Johns Hopkins University says, “We are probing the very limits of the star forming process.”.
The question of whether an object that resembles a young Jupiter could have turned into a star in the right circumstances is crucial to comprehending the formation of both stars and planets. “.”.
There are two methods by which we could construct a cosmic object. According to theory, stars form top-down: a clump in a sufficiently dense cloud of gas and dust collapses under gravity, accumulating mass from a disk of material that swirls around it until the pressure and heat at the center of the clump reach a level that ignites hydrogen fusion.
From the material left in the disk after the star completes its formation, at least some planets are believed to form through a bottom-up process. In this scenario, material clumps first adhere to one another electrostatically and then gravitationally, accumulating enough material in the end to form a differentiated core and mantle.
Where these formation mechanisms overlap is not evident. This inquiry led the scientists to direct JWST toward NGC 1333, a nebula in Perseus that is home to numerous clusters of young stars that have just begun to form from the gas inside.
“To search for the faintest members of a young star cluster, we used Webb’s unprecedented sensitivity at infrared wavelengths, seeking to address a fundamental question in astronomy: How light an object can form like a star?” says Johns Hopkins University astrophysicist Ray Jayawardhana.
Apparently, massive exoplanets circling nearby stars share a mass with the tiniest free-floating objects that form like stars. “.”.
According to astronomers’ estimates, the Milky Way may contain billions of rogue planets. Much of these would have formed normally, as the remains of the meal consumed by a newborn star; intense gravitational interactions could release these worlds from their stellar anchors and send them on star-free adventures (or get sucked into the gravitational pull of an alien star).
But some rogue planets might begin their development in a similar manner to stars. We are aware of a class of objects known as brown dwarfs, which have masses between 13 and 85 times that of Jupiter and form similarly to stars but lack sufficient mass to undergo hydrogen fusion. The fusion of deuterium, a type of heavy hydrogen that requires less pressure and heat, can occur in these objects because they are massive enough to support it. They have a faint glow.
According to modeling, a planet can form bottom-up through core accretion to a maximum mass of less than 10 Jupiters. Furthermore, because NGC 1333 is a young galaxy, both the accretion and the gravitational interactions necessary to push the constituents out into the vast cosmic void would require time.
Consequently, Langeveld and his colleagues assumed that the six objects that JWST observed to be five to ten times the mass of Jupiter originated from gravitational collapse. This was verified when they discovered disks surrounding every one of the comparatively small objects, which resembled miniature baby stars.
“Our findings validate that planetary mass objects are created by nature through a minimum of two distinct processes – the contraction of a gas and dust cloud during star formation, and in gas and dust disks surrounding young stars, similar to Jupiter in our solar system,” notes Jayawardhana.
It’s interesting to note that the researchers did not discover any rogue worlds smaller than five Jupiters, despite the fact that JWST is sensitive enough to detect even smaller objects. This implies that this is the threshold. Planet formation via core accretion is probably required below that mass.
The results of the team’s investigation indicate that these objects are abundant, making up as much as 10% of all the objects in the cluster under investigation. Further obscuring the distinction between a planet and its moons and a star and its planets is the discovery of these worlds, which raises intriguing possibilities.
Astrophysicist Aleks Scholz of the University of St Andrews in the UK says, “Those tiny objects with masses comparable to giant planets may themselves be able to form their own planets.”. It’s possible that this is the nursery of a tiny, much smaller planetary system than our own Solar System. “.”.
