3/13/2023 0 Comments Low gravity field trine 2We combine our new rotation periods with the literature to investigate the effects of mass on angular momentum evolution. We speculate that the observed range of amplitudes within a spectral type may be influenced by secondary effects such as viewing inclination and/or rotation period. We examine the variability amplitudes of young objects and find an enhancement in maximum amplitudes compared to field dwarfs. In contrast, the field dwarf variability occurrence rate drops for spectral types >L9. We detect variability in 13 young objects, and find that young brown dwarfs are highly likely to display variability across the L2–T4 spectral type range. The 23 objects in our sample show robust signatures of youth and share properties with directly imaged exoplanets. We present a survey for photometric variability in young, low-mass brown dwarfs with the Spitzer Space Telescope. The results are encouraging for future variability searches in directly-imaged exoplanets with facilities such as the James Webb Space Telescope and 30-meter telescopes. Within the AB Doradus group, we find a high variability occurrence rate and evidence for common angular momentum evolution. The rotation periods of companion brown dwarfs and planetary-mass objects are consistent with those of isolated objects with similar ages and masses, suggesting similar angular momentum histories. The spectra reveal resolved molecular lines from H$_$), likely due to the small number of measured periods for old, low-mass objects. The data were taken with the OSIRIS integral field spectrograph at the W.M. We present moderate-resolution ($R\sim4000$) $K$ band spectra of the planetary-mass companion VHS 1256 b.
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