The star has blown their atmospheres away
A cuarenta años luz de la Tierra, una estrella pequeña y temperamental llamada TRAPPIST-1 lanza seis erupciones diarias que podrían estar despojando de atmósferas a los siete mundos que la orbitan. Un equipo de la Universidad de Colorado Boulder, valiéndose del Telescopio Espacial James Webb, ha logrado reconstruir la maquinaria interna de esas explosiones, trazando el camino desde la ruptura de campos magnéticos hasta los chorros de electrones que calientan el plasma estelar. En el horizonte de esta investigación yace una pregunta que la humanidad lleva siglos formulando: ¿puede alguno de esos mundos, en particular TRAPPIST-1e, conservar aún las condiciones necesarias para albergar vida?
- Seis veces al día, TRAPPIST-1 detona erupciones que bombardean sus planetas con radiación capaz de arrancar atmósferas enteras, convirtiendo mundos potencialmente habitables en rocas desnudas.
- Los planetas interiores del sistema ya parecen haber perdido la batalla: los científicos creen que son esferas áridas, despojadas por décadas o siglos de asalto estelar ininterrumpido.
- El obstáculo central de la investigación era invisible: Webb puede ver el calor de una erupción, pero no el mecanismo que la desencadena, lo que obligó al equipo a desarrollar modelos computacionales para reconstruir la causa a partir del efecto.
- Un hallazgo inesperado complica el panorama: los haces de electrones de TRAPPIST-1 son diez veces menos potentes que los de estrellas similares, pero eso no significa que sus planetas estén a salvo, sino que la naturaleza exacta del daño debe recalcularse.
- La investigación apunta ahora a TRAPPIST-1e, el planeta en la zona habitable, para determinar si su atmósfera ha sobrevivido y si aún podría sostener las condiciones mínimas para la vida.
A cuarenta años luz de la Tierra, la estrella TRAPPIST-1 es pequeña en masa pero enorme en furia: erupciona seis veces al día, lanzando explosiones de energía sobre los siete planetas que la orbitan, tres de ellos situados en la zona donde el agua líquida podría existir. Un nuevo estudio liderado por Ward Howard, investigador de la Universidad de Colorado Boulder y becario NASA Sagan, utilizó datos del Telescopio James Webb para adentrarse en esas explosiones y comprender el daño que infligen a los mundos cercanos.
El problema de fondo es que Webb solo puede ver el resultado de una erupción, no su origen. Para reconstruir la maquinaria interna, el equipo combinó observaciones de seis erupciones registradas entre 2022 y 2023 con simulaciones computacionales desarrolladas por el coautor Adam Kowalski. El proceso funciona como una investigación forense: se parte del rastro visible para deducir la causa. Según el modelo, cuando los campos magnéticos de la estrella alcanzan su punto de quiebre, liberan haces de electrones que atraviesan la atmósfera estelar, calientan el plasma y desencadenan el destello.
Un resultado sorprendió al equipo: los haces de electrones de TRAPPIST-1 son aproximadamente diez veces menos potentes que los detectados en estrellas similares. Lejos de ser una buena noticia, este dato obliga a recalcular con precisión qué tipo de radiación —desde luz visible hasta rayos X— alcanza cada planeta y cómo altera su química atmosférica. Los planetas interiores, según Howard, probablemente ya son rocas desnudas. Pero TRAPPIST-1e, en la zona habitable, podría conservar vestigios de una atmósfera parecida a la de la Tierra. La siguiente fase de la investigación buscará trazar, erupción por erupción, qué ha soportado cada mundo y qué podría aún ser capaz de sostener.
Forty light-years from Earth, a small star called TRAPPIST-1 is throwing tantrums. Six times a day, it erupts in violent flares—sudden explosions of energy that rake across seven orbiting worlds, three of which sit in the zone where liquid water might exist. The star itself is modest by cosmic standards: less than a tenth the mass of our Sun, barely larger than Jupiter. Yet its temperament is anything but small. A new study, led by researchers at the University of Colorado Boulder and published in The Astrophysical Journal Letters, has used data from the James Webb Space Telescope to peer inside these explosions and understand what they're doing to the planets nearby.
Ward Howard, the study's lead author and a NASA Sagan Fellow, frames the problem plainly: the innermost planets orbiting TRAPPIST-1 are likely barren rock, stripped naked by the star's relentless bombardment. "We believe the inner planets of TRAPPIST-1 are just bare rocks because the star has blown their atmospheres away," he explains. For scientists trying to determine whether any world around this star could harbor life, that's a sobering reality. But understanding how the star does this damage is the first step toward figuring out which planets, if any, might have survived the onslaught.
The challenge in studying stellar flares is fundamental: you can see the explosion, but not what caused it. Webb detects the heat released during a flare, the final signature of the event. What it cannot directly observe is the machinery underneath. Howard and his team developed a new approach. All stars are wrapped in magnetic fields that twist and bend, shaping the plasma in their outer layers. Sometimes these fields reach a breaking point. When the magnetic structure snaps, it releases a beam of electrons that races through the star's atmosphere, colliding with plasma and heating it violently. That's when the star flares. "Once you have hot enough plasma, it glows," Howard says.
The researchers analyzed six flares recorded by Webb between 2022 and 2023. To work backward from the observed explosion to the electron beam that triggered it, they used new computer models developed by Adam Kowalski, a coauthor on the study. These simulations let them reverse-engineer what kind of initial process produced each observed flash. The technique is like reconstructing a crime from its aftermath—you see the result, and you work to deduce the cause.
One surprising finding emerged: TRAPPIST-1's flares are weaker than expected. The electron beams powering these explosions are roughly ten times less potent than those detected in similar stars elsewhere. This might sound like good news for the planets, but Howard and his team see it differently. The weakness itself is informative. Those electron beams generate radiation across a broad spectrum, from visible light to X-rays. Understanding the full range of that radiation is crucial for determining how flares alter the chemistry of planetary atmospheres.
One planet in particular draws attention: TRAPPIST-1e, which orbits in the habitable zone. It might retain traces of an atmosphere similar to Earth's. For Howard, reconstructing the flares is essential to testing that possibility. "If we can simulate these events using a computer model, we can reconstruct how a flare could influence the radiation environment around each of these planets," he says. That radiation environment is what determines whether an atmosphere survives or gets stripped away. The next phase of research will use these models to map out, flare by flare, what each world around TRAPPIST-1 has endured—and what it might still be capable of sustaining.
Notable Quotes
We believe the inner planets of TRAPPIST-1 are just bare rocks because the star has blown their atmospheres away.— Ward Howard, lead author of the study
If we can simulate these events using a computer model, we can reconstruct how a flare could influence the radiation environment around each of these planets.— Ward Howard
The Hearth Conversation Another angle on the story
Why does a star six times weaker than the Sun matter so much to habitability researchers?
Because TRAPPIST-1 is close enough and active enough that we can actually study it in detail. It's a laboratory. And because three of its planets sit in the habitable zone—the region where water could exist as liquid. That proximity to a violent star is the whole tension.
So the flares are stripping away atmospheres. How do you know that's what's happening?
You don't directly observe an atmosphere being stripped. You see a bare rock where there should be an atmosphere, and you see a star that flares constantly. The new work reconstructs the physics of the flares themselves—the electron beams, the magnetic breakdowns—so you can model what that radiation does to an atmosphere over time.
The flares are weaker than expected. Doesn't that help the planets?
It's complicated. Weaker flares might mean less immediate damage per event. But TRAPPIST-1 flares six times a day. The cumulative effect over billions of years is what matters. And understanding the spectrum of radiation—not just the total energy, but the mix of wavelengths—tells you which molecules in an atmosphere get destroyed first.
What happens to TRAPPIST-1e specifically?
That's the open question. It's in the habitable zone, so it's far enough from the star that some protection is possible. But whether it kept an atmosphere, or built one back, or never had one—that depends on the exact radiation environment the flares create. That's what these models are trying to map.
So this research doesn't answer whether life exists there.
No. It answers whether the conditions for life could exist there. It's the foundation question. You can't have life without an atmosphere to breathe and to shield you from radiation. This work is about whether TRAPPIST-1e could have kept one.