Study Reveals Atmospheric Chemistry of Planetary-Mass Object at Planet-Brown Dwarf Boundary
Astronomers used high-resolution spectroscopy to measure the atmospheric composition of 2MASS J0249-0557 c, a ~12 Jupiter-mass object orbiting brown dwarfs in the β Pictoris young moving group. The measurements show a C/O ratio of 0.57, metallicity of [M/H] = 0.18, and a 12CO/13CO ratio of 95, with compositions consistent with benchmark brown dwarfs in the same region. These findings support gravitational collapse as the likely formation mechanism for this object and provide a baseline for understanding how planets and brown dwarfs form at the boundary between these two categories.
Researchers conducted a detailed atmospheric analysis of 2MASS J0249-0557 c, a planetary-mass companion with a mass of approximately 12 Jupiter masses orbiting a pair of brown dwarfs. Using CRIRES+ spectroscopic data from the Very Large Telescope, they employed atmospheric retrieval techniques with radiative transfer modeling to determine precise chemical and isotopic abundances. The retrieved values include a C/O ratio of 0.57±0.01, solar-like metallicity of [M/H] = 0.18±0.05, and a 12CO/13CO ratio of 95+23−17. The team also analyzed two benchmark brown dwarfs in the same young moving group for comparison. The compositional consistency across all three substellar objects, combined with the wide orbital separation of 2MASS J0249-0557 c from its host system, supports formation through gravitational collapse rather than disk-based planetary assembly. These results establish a compositional baseline for comparing other planetary members of the β Pictoris young moving group and help constrain formation mechanisms at the planet-brown dwarf boundary.
What different sources said
- arXiv astro-phCenter
Chemistry and Isotope Ratios of Substellar Atmospheres in the $\beta$ Pictoris Young Moving Group and Vicinity
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