Native-resolution retrievals on 0.97-5.27 micron JWST spectra of VHS 1256 b find a ~79% cloud deck, solar-like metallicity and C/O, and depleted 18O in a partially cloudy disequilibrium atmosphere.
Constraints on the Spin Evolution of Young Planetary-Mass Companions
4 Pith papers cite this work. Polarity classification is still indexing.
abstract
Surveys of young star-forming regions have discovered a growing population of planetary-mass (<13 M_Jup) companions around young stars. There is an ongoing debate as to whether these companions formed like planets (that is, from the circumstellar disk), or if they represent the low-mass tail of the star formation process. In this study we utilize high-resolution spectroscopy to measure rotation rates of three young (2-300 Myr) planetary-mass companions and combine these measurements with published rotation rates for two additional companions to provide a look at the spin distribution of these objects. We compare this distribution to complementary rotation rate measurements for six brown dwarfs with masses <20 M_Jup, and show that these distributions are indistinguishable. This suggests that either that these two populations formed via the same mechanism, or that processes regulating rotation rates are independent of formation mechanism. We find that rotation rates for both populations are well below their break-up velocities and do not evolve significantly during the first few hundred million years after the end of accretion. This suggests that rotation rates are set during late stages of accretion, possibly by interactions with a circumplanetary disk. This result has important implications for our understanding of the processes regulating the angular momentum evolution of young planetary-mass objects, and of the physics of gas accretion and disk coupling in the planetary-mass regime.
years
2026 4representative citing papers
High-resolution M-band spectroscopy detects super-stellar SiO in TWA 5 B, implying no significant magnesium-silicate clouds and formation consistent with core accretion beyond the CO snowline or gravitational instability with solid enrichment.
Discovery of an L2 brown dwarf companion (mass 53 M_Jup, age ~280 Myr) to HIP 17453 A via proper-motion confirmed imaging and spectroscopy.
Retrievals on six isolated brown dwarfs yield near-solar C/O (0.51-0.63), metallicities, and 12C/13C ratios (91-155) supporting molecular cloud fragmentation origin.
citing papers explorer
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Native-resolution retrievals of VHS 1256-1257 b spanning the JWST/NIRSpec wavelength range: Chemical composition of a partially cloudy atmosphere
Native-resolution retrievals on 0.97-5.27 micron JWST spectra of VHS 1256 b find a ~79% cloud deck, solar-like metallicity and C/O, and depleted 18O in a partially cloudy disequilibrium atmosphere.
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The CRIMSON survey I: super-stellar SiO in the directly imaged companion TWA 5 B from high-resolution M-band spectroscopy
High-resolution M-band spectroscopy detects super-stellar SiO in TWA 5 B, implying no significant magnesium-silicate clouds and formation consistent with core accretion beyond the CO snowline or gravitational instability with solid enrichment.
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The Companions to B and A Stars Snapshot (C-BASS) Survey: I. Discovery of a Young Brown Dwarf Companion to HIP 17453
Discovery of an L2 brown dwarf companion (mass 53 M_Jup, age ~280 Myr) to HIP 17453 A via proper-motion confirmed imaging and spectroscopy.
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The ESO SupJup Survey XI. Atmospheric properties of six isolated M- and L-type dwarfs with CRIRES+
Retrievals on six isolated brown dwarfs yield near-solar C/O (0.51-0.63), metallicities, and 12C/13C ratios (91-155) supporting molecular cloud fragmentation origin.