Traditional theories suggested these objects might have been flung from their original star systems or formed close to stars but were later ejected.
A groundbreaking theory suggests that bizarre, starless Jupiter-mass planet pairs may be the remnants of failed stars, reshaped by the intense radiation of massive neighboring stars. These discoveries are changing our understanding of planet and star formation in the cosmos.
Astronomers using the James Webb Space Telescope (JWST) have discovered peculiar objects floating freely in space. Known as Jupiter-Mass Binary Objects (JuMBOs), these pairs of gas giants are unlike anything previously observed. Instead of orbiting a star, the two planetary-sized bodies orbit each other at distances ranging from 25 to 400 astronomical units (AU)—equivalent to 25 to 400 times the distance between Earth and the Sun.
Located in the Orion Nebula, JuMBOs are enormous gas giants with masses between 0.7 and 30 times that of Jupiter. Their lack of a parent star raises intriguing questions: How did they form, and what keeps them bound in such vast separations?
Traditional theories suggested these objects might have been flung from their original star systems or formed close to stars but were later ejected. However, a new study challenges this view, suggesting that JuMBOs may not be planets at all but rather failed stars shaped by their harsh environments.
Failed Stars or Planets? A Bold New Hypothesis
Stars are born within pre-stellar cores—dense clouds of gas and dust that collapse under gravity to form protostars. Occasionally, these cores fragment, giving rise to binary or triplet star systems. However, such stellar nurseries can be violent places, especially in regions like the Orion Nebula, where massive stars emit intense radiation.
Astrophysicists Anthony Whitworth and Hans Zinnecker theorized two decades ago that this radiation could strip away the outer layers of pre-stellar cores. This process compresses the core’s center, potentially turning what would have been a star into a brown dwarf or a massive planet-like object. Building on this idea, the new study suggests that JuMBOs could be the remnants of disrupted binary stars, reshaped by their extreme environments.
The researchers tested this hypothesis using computer simulations. By modeling pre-stellar cores exposed to high-energy radiation, they found that the resulting objects had masses and separations consistent with the observed JuMBOs. This suggests that intense radiation from nearby massive stars could sculpt embryonic binary stars into the rogue planet pairs we see today.
Expanding the Search Beyond Orion
While the findings offer a compelling explanation for JuMBOs, astronomers emphasize the need for further evidence. Richard Parker, senior author of the study, points to regions like the Scorpius-Centaurus association—home to thousands of stars—as potential places to confirm their hypothesis.
Despite the promising results, Parker acknowledges that multiple formation pathways for JuMBOs are likely. “We know so little about these objects that it’s entirely possible they form in several different ways,” he said.
The discovery of JuMBOs challenges conventional ideas about planet and star formation, offering new insights into the complex processes shaping our universe.
