by Last year, using the James Webb Space Telescope (JWST), astronomers made a startling discovery of several free-floating, planetary-mass objects in the Orion nebula that cast doubt on their ideas about planet and star formation. And now, new research has further deepened the mystery of Jupiter-mass binary objects, or JuMBOs, as they are called.
JuMBOs aren’t stars, but they aren’t really planets either. Mark McCaughrean, senior science adviser at the European Space Agency (ESA), and colleagues first discovered the objects in the Orion nebula. This nebula, also known as Messier 45, is a star birth region and is located approximately 1,350 light years from Earth.
Adding to that view, a team of researchers used data collected by the Karl G. Jansky Very Large Array (VLA) at the US Science Foundation’s National Radio Astronomy Observatory to study radio signals coming from some of the JuMBOs. that. But, despite McCaughrean and his colleagues finding 40 pairs of JuMBOs, only one pair of these strange objects has been seen emitting radio waves.
“JuMBO is already difficult to account for with star and planet formation models, and now we have this strong radio emission, and it’s not clear what it’s producing,” Luis F. Rodriguez, team member and professor at the National Autonomous. University of Mexico, said Space.com.
The radio signal was seen coming from both components of “JuMBO 24.” Both components appear to be about 11 times the mass of Jupiter, making them the largest of their kind seen by the JWST, while the others are between 3 and 8 times more massive is the most massive planet in the solar system.
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The signal was much stronger than radio signals associated with objects like JuMBO, aka brown dwarfs. Brown dwarfs are objects that are born in the same way as stars, but fail to accumulate enough mass to fuel the fusion of hydrogen into helium at their cores like your standard star does. Because of this failure to initiate the process that defines a star in its main sequence life, brown dwarfs exist, with masses between 13 and 75 times that of Jupiter, earning the unfortunate nickname “failed stars.”
“With regular stars and brown dwarfs, there are mechanisms that explain radio emission. For JuMBO, we have no mechanism to explain this very strong radio emission,” said Rodriguez.
Not stars or planets
JuMBOs are hot, gassy, and relatively small bodies that exist in pairs, a combination that defies common observations of binary stars. Generally, scientists believe that the most massive stars prefer only life in binary pairs; the smaller the stellar body, the less likely it is to be found in a binary partnership.
Binary stars are born when dense patches in a disk of gas and dust fragments collapse and gather mass, forming a few stars. About 75% of massive stars are found in binaries, and this percentage drops to 50% for stars around the size of the Sun and 25% for smaller stars. Chances are you’ll find a brown dwarf in a binary close to zero. This means that JuMBOs, which are under the mass limit for brown dwarfs, should not actually be in binaries if they are indeed formed as stars.
But if JuMBOs are formed like stars, the large number of them found in Orion would suggest that the binary frequency of stellar bodies is somehow “jumping up” at masses below the brown dwarf. This is something that cannot yet be accounted for in star formation models.
So if these planetary mass objects cannot form according to current star formation models, they were born like planets, surely? Well, maybe, but it is equally difficult to explain JuMBO pairs if they are created like planets, which form from material left in the same disks of gas and dust that gave birth to their parent stars.
Some planets are known to be ejected from their host star as a result of internal or external gravitational effects, such as encounters with other star systems. From there, those worlds become “rogue planets” and wander the cosmos without a parent star, just as JuMBOs appear to be orphans in Orion. However, the process that creates these orphan planets is so violent that it should split any pairs of planets that are gravitationally bound.
The ejection mechanism cannot account for why planets like Jupiter would have been ejected from each other. That means the planetary evolution pathway can explain how JuMBO came to be, but not why they still have their binary partners. Even if such a thing could happen on certain occasions, there is not a pair or two of JuMBO in Orion. There are 42.
These JuMBOs are probably not the result of a single freak eviction incident.
JuMBOs in Orion become even more challenging to explain when you consider the fact that some of the binaries they inhabit are very widely spaced. A few JuMBOs appear to be separated by up to 300 times the distance between Earth and the sun. Others fall as far apart as the width of the entire solar system, meaning they are very weakly gravitationally bound.
Radio signals from JuMBO24 are different from life
Rodriguez and his colleagues knew Orion well, having previously studied the nebula with the VLA. So, when JuMBOS showed the infrared data of the JWST, they decided to follow up by searching archival data of radio wave observations to search for radio wave counterparts in these detections.
“We said, ‘Hey, let’s go and see if one of the JuMBOs has been detected before.’ We took archival VLA data and calibrated it, finding JuMBO 24 in all three ‘ranges’ of data,” said Rodriguez. “We detected radio wave emissions from the most massive JuMBO binary, but it is not clear why the others were not detected in radio waves.”
He explained that the team thinks the other JuMBOs may also be emitting radio waves because their components are smaller than the two 11-Jupiter mass objects in the JuMBO 24 binary.
“We are looking for time with the VLA to create deeper images with the hope of possibly finding a few more, and this will allow us to better understand the process that is creating radio waves from JuMBOs,” said Rodriguez.
These deeper observations may also reveal the velocity of the JuMBOs in the sky in relation to the Orion nebula. Rodriguez explained that if the JuMBOs are moving fast, this would suggest that they formed like planets around stars and were expelled from these systems. On the other hand, he pointed out that if these strange celestial bodies are almost stationary in relation to Orion, this would suggest that they are formed from huge clouds of gas and dust that are collapsing like stars.
Either explanation would prompt a rethinking of how stars and planets form and evolve in their respective systems.
Radio signals may also be an indicator of intelligent life on Earth, but Rodriguez is quick to dispel speculation that this is the case for JuMBO 24.
“Life in Jupiter-like objects without a solid surface is not considered, and JuMBOs would be pretty cool since there are no stars associated with them,” he said. “If JuMBOs had Moons, one could speculate that life could exist in a subsurface ocean as is suspected in Europa, Ganymede, and Enceladus. However, the objects in young Orion are only a few million years old. [compared to our 4.6 billion-year-old solar system]meaning that there is unlikely to be enough time for life to appear on these moons if they exist.”
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Rodriguez added that in the unlikely event that these objects or moons around them could support life, researchers hunting for alien organisms on JuMBO 24 would also need to explain why radio emissions are coming from both components of the This strange binary, not just one.
So, while JuMBOs may be the astronomical discovery of the 2020s and are interesting targets for scientists who want to better understand the formation of stars and planets, they may not be great targets for scientists investigating the possibility of extraterrestrial life of the solar system.
The team’s research was published in January in the Astrophysical Journal Letters.
