Methane Detected in Atmosphere of Closest T Dwarf to Earth
Posted: Tue Apr 08, 2025 10:16 am
Using the 10.4-meter Gran Telescopio Canarias (GTC), a team of European astronomers has detected methane in the atmosphere of WISEA J181006.18−101000.5—the closest known T dwarf to Earth. The results were presented in a study published on March 28 via the arXiv preprint server.
Brown dwarfs are celestial bodies that fall between planets and stars in terms of mass, typically ranging from 13 to 80 times the mass of Jupiter. Among these are T dwarfs, a subclass characterized by effective temperatures between 500 and 1,500 K. These objects are considered the coolest and least luminous among known substellar types. Though numerous brown dwarfs have been discovered, T dwarfs remain relatively rare, with only about 400 identified so far.
WISEA J181006.18−101000.5, commonly referred to as WISE1810, is a metal-poor T dwarf situated approximately 29 light years from Earth. It has a radius of around 0.65 Jupiter radii and is estimated to be about 17 times more massive than Jupiter. Its effective temperature is thought to lie between 800 and 1,300 K.
Earlier low-resolution observations in the near- and mid-infrared suggested WISE1810's atmosphere was dominated by hydrogen and water vapor but lacked detectable methane—a molecule typically used to identify T-type dwarfs. That changed with a new study led by Jerry Zhang of the University of La Laguna in Spain. Using GTC's Espectrógrafo Multiobjeto Infra-Rojo (EMIR), the team captured new near-infrared photometry of WISE1810, successfully detecting methane in its atmosphere.
https://github.com/BrentGNT/Arch2
https://github.com/TomGMN/ffkoa
https://github.com/BryanEMD/kkstb
https://github.com/CodyEGT/Sfumm
https://github.com/ErikBDT/Fcumg
https://github.com/DorianKVT/Mwum
https://github.com/JeremyEGT/Ahum9
https://github.com/AidenBMT/Wmumd
https://github.com/BlakeTNS/S2ugm
https://github.com/BrettKNO/Zadzmg
https://github.com/BrodyTNN/Cscofps
https://github.com/CalebSNT/Bmumg
https://github.com/CarterSMN/KtbsK
https://github.com/ChaseDNT/Trucg
https://github.com/CooperTRN/Sf2ueg
https://github.com/DaltonYNT/Ssumg
https://github.com/EthanGNM/Wwhug
https://github.com/JacksonMRT/Bwum
https://github.com/AtevenKLD/Wtmum
https://github.com/JoshBDO/Coum5
This discovery solidifies the object's classification as a T-type brown dwarf rather than an L-type, as had been previously debated. The team also reported no signs of carbon monoxide or atomic potassium in the atmosphere.
Based on their analysis, the researchers estimated WISE1810’s carbon abundance at -1.5 dex, suggesting an overall metallicity of about -1.7 dex. The object’s temperature was further constrained to approximately 1,000 K. The low metallicity likely explains the absence of atomic potassium, although a cooler temperature may also contribute.
Additionally, the team measured WISE1810’s heliocentric velocity at -83 km/s. This velocity aligns more closely with membership in the Milky Way’s thick disk rather than the halo, despite the object's extremely low metallicity.
Brown dwarfs are celestial bodies that fall between planets and stars in terms of mass, typically ranging from 13 to 80 times the mass of Jupiter. Among these are T dwarfs, a subclass characterized by effective temperatures between 500 and 1,500 K. These objects are considered the coolest and least luminous among known substellar types. Though numerous brown dwarfs have been discovered, T dwarfs remain relatively rare, with only about 400 identified so far.
WISEA J181006.18−101000.5, commonly referred to as WISE1810, is a metal-poor T dwarf situated approximately 29 light years from Earth. It has a radius of around 0.65 Jupiter radii and is estimated to be about 17 times more massive than Jupiter. Its effective temperature is thought to lie between 800 and 1,300 K.
Earlier low-resolution observations in the near- and mid-infrared suggested WISE1810's atmosphere was dominated by hydrogen and water vapor but lacked detectable methane—a molecule typically used to identify T-type dwarfs. That changed with a new study led by Jerry Zhang of the University of La Laguna in Spain. Using GTC's Espectrógrafo Multiobjeto Infra-Rojo (EMIR), the team captured new near-infrared photometry of WISE1810, successfully detecting methane in its atmosphere.
https://github.com/BrentGNT/Arch2
https://github.com/TomGMN/ffkoa
https://github.com/BryanEMD/kkstb
https://github.com/CodyEGT/Sfumm
https://github.com/ErikBDT/Fcumg
https://github.com/DorianKVT/Mwum
https://github.com/JeremyEGT/Ahum9
https://github.com/AidenBMT/Wmumd
https://github.com/BlakeTNS/S2ugm
https://github.com/BrettKNO/Zadzmg
https://github.com/BrodyTNN/Cscofps
https://github.com/CalebSNT/Bmumg
https://github.com/CarterSMN/KtbsK
https://github.com/ChaseDNT/Trucg
https://github.com/CooperTRN/Sf2ueg
https://github.com/DaltonYNT/Ssumg
https://github.com/EthanGNM/Wwhug
https://github.com/JacksonMRT/Bwum
https://github.com/AtevenKLD/Wtmum
https://github.com/JoshBDO/Coum5
This discovery solidifies the object's classification as a T-type brown dwarf rather than an L-type, as had been previously debated. The team also reported no signs of carbon monoxide or atomic potassium in the atmosphere.
Based on their analysis, the researchers estimated WISE1810’s carbon abundance at -1.5 dex, suggesting an overall metallicity of about -1.7 dex. The object’s temperature was further constrained to approximately 1,000 K. The low metallicity likely explains the absence of atomic potassium, although a cooler temperature may also contribute.
Additionally, the team measured WISE1810’s heliocentric velocity at -83 km/s. This velocity aligns more closely with membership in the Milky Way’s thick disk rather than the halo, despite the object's extremely low metallicity.