Utilizing new observations from the James Webb House Telescope (JWST), astronomers have found methane emission on a brown dwarf, an surprising discovering for such a chilly and remoted world. Printed within the journal Nature, the findings recommend that this brown dwarf may generate aurorae much like these seen on our personal planet in addition to on Jupiter and Saturn.
Extra large than planets however lighter than stars, brown dwarfs are ubiquitous in our photo voltaic neighborhood, with 1000’s recognized. Final 12 months, Jackie Faherty, a senior analysis scientist and senior training supervisor on the American Museum of Pure Historical past, led a group of researchers who had been awarded time on JWST to analyze 12 brown dwarfs. Amongst these was CWISEP J193518.59-154620.3 (or W1935 for brief) — a chilly brown dwarf 47 gentle years away that was co-discovered by Yard Worlds: Planet 9 citizen science volunteer Dan Caselden and the NASA CatWISE group. W1935 is a chilly brown dwarf with a floor temperature of about 400° Fahrenheit, or in regards to the temperature at which you’d bake chocolate chip cookies. The mass for W1935 is not well-known but it surely possible ranges between 6-35 occasions the mass of Jupiter.
After a variety of brown dwarfs noticed with JWST, Faherty’s group seen that W1935 seemed comparable however with one putting exception: it was emitting methane, one thing that is by no means been seen earlier than on a brown dwarf.
“Methane fuel is predicted in big planets and brown dwarfs however we normally see it absorbing gentle, not glowing,” mentioned Faherty, the lead creator of the research. “We had been confused about what we had been seeing at first however finally that reworked into pure pleasure on the discovery.”
Laptop modeling yielded one other shock: the brown dwarf possible has a temperature inversion, a phenomenon wherein the ambiance will get hotter with rising altitude. Temperature inversions can simply occur to planets orbiting stars, however W1935 is remoted, with no apparent exterior warmth supply.
“We had been pleasantly shocked when the mannequin clearly predicted a temperature inversion,” mentioned co-author Ben Burningham from the College of Hertfordshire. “However we additionally had to determine the place that additional higher ambiance warmth was coming from.”
To research, the researchers turned to our photo voltaic system. Specifically, they checked out research of Jupiter and Saturn, which each present methane emission and have temperature inversions. The possible trigger for this function on photo voltaic system giants is aurorae, subsequently, the analysis group surmised that they’d uncovered that very same phenomenon on W1935.
Planetary scientists know that one of many main drivers of aurorae on Jupiter and Saturn are high-energy particles from the Solar that work together with the planets’ magnetic fields and atmospheres, heating the higher layers. That is additionally the explanation for the aurorae that we see on Earth, generally known as the Northern or Southern Lights since they’re most extraordinary close to the poles. However with no host star for W1935, a photo voltaic wind can’t contribute to the reason.
There’s an attractive further motive for the aurora in our photo voltaic system. Each Jupiter and Saturn have energetic moons that sometimes eject materials into house, work together with the planets, and improve the auroral footprint on these worlds. Jupiter’s moon Io is essentially the most volcanically energetic world within the photo voltaic system, spewing lava fountains dozens of miles excessive, and Saturn’s moon Enceleadus ejects water vapor from its geysers that concurrently freezes and boils when it hits house. Extra observations are wanted, however the researchers speculate that one clarification for the aurora on W1935 could be an energetic, yet-to-be found moon.
“Each time an astronomer factors JWST at an object, there’s an opportunity of a brand new mind-blowing discovery,” mentioned Faherty. “Methane emission was not on my radar once we began this challenge however now that we all know it may be there and the reason for it so engaging I’m always on the look-out for it. That is a part of how science strikes ahead.”
Different authors on the research embrace Jonathan Gagne, Institute for Analysis on Exoplanets and Université de Montréal; Genaro Suarez, Dan Caselden, Austin Rothermich, and Niall Whiteford, American Museum of Pure Historical past; Johanna Vos, Trinity School Dublin; Sherelyn Alejandro Merchan, Metropolis College of New York; Caroline Morley, College of Texas; Melanie Rowland and Brianna Lacy, College of Texas, Austin; Rocio Kiman, Charles Beichman, Federico Marocco, and Christopher Gelino, California Institute of Expertise; Davy Kirkpatrick, IPAC; Aaron Meisner, NOIRLab; Adam Schneider, USNO; Marc Kuchner and Ehsan Gharib-Nezhad, NASA; Daniella Bardalez Gagliuffi, Amherst; Peter Eisenhardt, Jet Propulsion Laboratory; and Eileen Gonzales, San Francisco State College.
This work was supported partly by NASA and the House Telescope Science Institute.
