Something is wrong in our understanding of planet formation
En las profundidades de la Nebulosa de Orión, a 1.300 años luz de la Tierra, el telescopio espacial James Webb ha encontrado algo que ninguna mente científica anticipó: cuarenta pares de objetos con masa similar a la de Júpiter que orbitan entre sí en el vacío, sin estrella que los ancle, sin teoría que los explique. Bautizados como JuMBOs —Objetos Binarios de Masa Joviana—, estos cuerpos de apenas un millón de años de antigüedad desafían décadas de modelos sobre cómo nacen los planetas y las estrellas. Su existencia no es solo un misterio astronómico; es un recordatorio de que el cosmos guarda secretos más profundos que nuestras mejores preguntas.
- Cuarenta pares de objetos flotantes, sin estrella madre, sin explicación teórica: el hallazgo sacude los cimientos de la astrofísica moderna.
- Ningún modelo existente de formación planetaria o estelar predijo ni puede explicar cómo dos objetos de tan baja masa podrían formarse juntos y permanecer gravitacionalmente unidos en el espacio abierto.
- La posibilidad de que sean planetas expulsados simultáneamente de sus sistemas de origen y que aun así se mantuvieran ligados entre sí resulta, según los propios científicos, extraordinariamente difícil de sostener.
- La visión infrarroja del Webb resultó decisiva: estos objetos, aún calientes por la energía de su formación, son invisibles para telescopios convencionales pero brillan en el espectro infrarrojo.
- Observaciones programadas para principios de 2024 buscarán revelar la composición atmosférica y la masa precisa de los JuMBOs, mientras otros equipos rastrean si existen en regiones estelares más allá de Orión.
El telescopio espacial James Webb apuntó su cámara de infrarrojo cercano al Cúmulo del Trapecio, una región de formación estelar dentro de la Nebulosa de Orión, con la intención de buscar objetos aislados de baja masa. Lo que encontraron los investigadores Samuel G. Pearson y Mark J. McCaughrean fue algo completamente distinto: cuarenta pares de objetos con masas de entre 0,6 y 13 veces la de Júpiter, orbitando entre sí a distancias equivalentes a unas 200 veces la separación entre la Tierra y el Sol, y tardando entre 20.000 y 80.000 años en completar una sola vuelta. Los llamaron JuMBOs.
Estos objetos tienen apenas un millón de años de antigüedad —infantes cósmicos, en palabras de McCaughrean, comparados con los 4.570 millones de años de nuestro sistema solar. Aún irradian calor residual de su formación, lo que los hace detectables para Webb en el infrarrojo, aunque prácticamente invisibles en luz visible. Sus temperaturas oscilan entre los 500 y los 1.300 grados Celsius.
El verdadero peso del hallazgo no está en los números, sino en lo que implican: ninguna teoría existente sobre la formación de planetas o estrellas puede explicar su origen. Los planetas nacen en los discos de gas que rodean estrellas jóvenes; las estrellas, del colapso gravitacional de nubes de gas. Los JuMBOs no encajan en ninguno de esos moldes. La hipótesis de que sean planetas errantes expulsados de sus sistemas de origen tropieza con un obstáculo insalvable: sería extraordinariamente improbable que dos objetos fueran expulsados al mismo tiempo y permanecieran ligados gravitacionalmente entre sí.
"Lo que aprendemos de esto es que algo está mal en nuestra comprensión de la formación de planetas, de estrellas, o de ambas", admitió Pearson. El equipo ha enviado dos artículos a revistas científicas, con resultados preliminares ya disponibles en arXiv. Las observaciones previstas para 2024 podrían ofrecer nuevas pistas sobre la composición y masa de estos objetos, mientras la comunidad científica comienza a preguntarse si los JuMBOs existen también en otras regiones del universo donde nacen las estrellas.
The James Webb Space Telescope has revealed something astronomers did not expect to find in the Orion Nebula: pairs of objects that look like planets, orbiting each other in the void, that no existing theory of planetary formation can explain.
The Orion Nebula sits 1,300 light-years from Earth, a luminous cloud of dust and gas visible as the sword in the constellation Orion. It has long been a favorite hunting ground for astronomers—a place where stars are born, where young stellar disks swirl around newborn suns, where brown dwarfs (objects too small to ignite nuclear fusion, yet too massive to be planets) drift in the darkness. When researchers Samuel G. Pearson and Mark J. McCaughrean pointed Webb's near-infrared camera at the Trapezium Cluster, a star-forming region roughly a million years old and crowded with thousands of young stars, they were looking for isolated objects of low mass. What they found instead was a puzzle.
They discovered 40 pairs of objects with masses between 0.6 and 13 times that of Jupiter, orbiting each other across vast distances—roughly 200 times the distance from Earth to the Sun—and taking between 20,000 and 80,000 years to complete a single orbit. The scientists named them Jupiter-Mass Binary Objects, or JuMBOs. Some have more mass than Jupiter itself, yet they will reach roughly the same size, only slightly larger. The objects are young, astronomically speaking: about a million years old. Our solar system, by contrast, is 4.57 billion years old. McCaughrean, the European Space Agency's principal science advisor, offered a vivid comparison: if the Sun is middle-aged, these objects in Orion are three-day-old infants. They still glow and radiate heat from the energy released during their formation—which is precisely why Webb can see them at all.
The discovery upends decades of theoretical work. Stars form when giant clouds of gas and dust collapse under gravity. Planets form in the disks of gas and dust that spin around young stars. But no existing model explains how JuMBOs came to be, or why they appear in such numbers in Orion. Some might argue they are rogue planets—objects of planetary mass cast adrift in space, no longer orbiting any star. Yet rogue planets typically begin their lives orbiting stars before being ejected. It would be extraordinarily difficult to explain how two rogue planets were ejected simultaneously and remained gravitationally bound to each other. "The scientists have been working on theories and models of star and planet formation for decades, but none of them anticipated finding pairs of very low-mass objects floating alone in space," Pearson said. "What we learn from this is that something is wrong in our understanding of planet formation, star formation, or both."
The temperatures of these objects range from 1,000 to 2,300 degrees Fahrenheit. They are gaseous bodies, still warm from their birth. Webb's infrared vision proved essential to their detection—these objects are faint in visible light but brighter in the infrared spectrum. "The James Webb is the most powerful infrared telescope ever built, and these observations simply would not be possible without it," Pearson noted. The research team has submitted two papers to academic journals, with preliminary findings already available on arXiv, a preprint server where scientists share work before formal publication.
Questions remain abundant. How did the JuMBOs form? Why are they present in such abundance in Orion? Might they exist elsewhere? Observations scheduled for early 2024 could reveal the atmospheric compositions of these objects and provide precise measurements of their masses. Other research teams may search for JuMBOs in different star-forming regions. For now, Pearson captured the essential bewilderment: "The main question is: 'What?! Where did that come from?' It is so unexpected that it will take many future observations and models to explain it."
Citações Notáveis
The scientists have been working on theories and models of star and planet formation for decades, but none of them anticipated finding pairs of very low-mass objects floating alone in space.— Samuel G. Pearson, European Space Agency researcher
What we learn from this is that something is wrong in our understanding of planet formation, star formation, or both.— Samuel G. Pearson
A Conversa do Hearth Outra perspectiva sobre a história
So we're looking at pairs of objects that seem to be planets, but they're not orbiting stars. What makes that so strange?
Everything we thought we understood about how planets form assumes they're born in disks of dust and gas around young stars. These JuMBOs are just... floating together in space, orbiting each other. There's no star involved. No model predicted this.
But couldn't they be planets that got kicked out of their systems?
That's the first thing astronomers thought of. But here's the problem: you'd need two planets to be ejected at exactly the same moment and somehow stay gravitationally bound to each other. The odds are vanishingly small. And we're seeing forty pairs of them, not just one or two flukes.
How old are these objects?
About a million years old. They're still glowing from the heat of their formation. Our sun is 4.5 billion years old, so these are infants—three days old in cosmic terms. That's actually how Webb can see them at all. They're still warm enough to shine in infrared.
What happens next? Do astronomers just accept that their theories are incomplete?
They have to. Pearson was direct about it: something fundamental is wrong with how we understand planet and star formation. The next step is more observations—looking at their atmospheres, measuring their masses precisely, searching for JuMBOs in other nebulae. But the real work is going to be theoretical. Someone has to figure out how these things actually form.
Does this change how we think about planets elsewhere in the universe?
It should. If we've been wrong about formation in Orion, we might be wrong about other places too. It's humbling, really. We built the most powerful infrared telescope ever made, pointed it at a nebula we've studied for decades, and found something nobody expected.