Tracing the Top-of-the-atmosphere and Vertical Cloud Structure of a fast-rotating late T-dwarf

Abstract

Only a handful of late-T brown dwarfs have been monitored for spectro-photometric variability, leaving incomplete the study of the atmospheric cloud structures of the coldest brown dwarfs, that share temperatures with some cold, directly-imaged exoplanets. 2MASSJ00501994-332240 is a T7.0 rapidly rotating, field brown dwarf that showed low-level photometric variability in data obtained with the Spitzer Space telescope. We monitored 2MASSJ00501994-332240 during ~2.6 hr with MOSFIRE, installed at the Keck I telescope, with the aim of constraining its near-infrared spectro-photometric variability. We measured fluctuations with a peak-to-peak amplitude of 1.48+\-0.75% in the J-band photometric light curve, an amplitude of 0.62+/-0.18% in the J-band spectro-photometric light curve, and an amplitude of 1.26+/-0.93% in the H-band light curve, and an amplitude of 5.33+/-2.02% in the CH_4-H_2O band light curve. Nevertheless, the Bayesian Information Criterion does not detect significant variability in any of the light curves. Thus, given the detection limitations due to the MOSFIRE sensitivity, we can only claim tentative low-level variability for 2M0050-3322 in the best-case scenario. The amplitudes of the peak-to-peak fluctuations measured for 2MASSJ00501994-332240 agree with the variability amplitude predictions of General Circulation Models for a T7.0 brown dwarf for an edge on object. Radiative-transfer models predict that the Na_2S and KCl clouds condense at pressures lower than that traced by the CH_4-H_2O band, which might explain the higher peak-to-peak fluctuations measured for this light curve. Finally, we provide a visual recreation of the map provided by General Circulation Models and the vertical structure of 2MASSJ00501994-332240 provided by radiative-transfer models.

arXiv commentAccepted at AJ June 13 2022

References in corpus (44)

• Astropy: A Community Python Package for Astronomy
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• Optimal Techniques in Two-dimensional Spectroscopy: Background Subtraction for the 21st Century
• The Hawaii Infrared Parallax Program. I. Ultracool Binaries and the L/T Transition
• Discovery and spectroscopy of the young Jovian planet 51 Eri b with the Gemini Planet Imager
• A Unified Near Infrared Spectral Classification Scheme for T Dwarfs
• Neglected Clouds in T and Y Dwarf Atmospheres
• Gaseous Mean Opacities for Giant Planet and Ultracool Dwarf Atmospheres over a Range of Metallicities and Temperatures
• Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime
• Atmospheric Chemistry in Giant Planets, Brown Dwarfs, and Low-Mass Dwarf Stars II. Sulfur and Phosphorus
• Weather on Other Worlds. II. Survey Results: Spots Are Ubiquitous on L and T Dwarfs
• Fingering convection and cloudless models for cool brown dwarf atmospheres
• Photometric Variability of the T2.5 Brown Dwarf SIMP J013656.5+093347; Evidence for Evolving Weather Patterns
• HST Spectral Mapping of L/T Transition Brown Dwarfs Reveals Cloud Thickness Variations
• Strong Brightness Variations Signal Cloudy-to-Clear Transition of Brown Dwarfs
• Magnetospherically driven optical and radio aurorae at the end of the stellar main sequence
• Vertical Atmospheric Structure in a Variable Brown Dwarf: Pressure-dependent Phase Shifts in Simultaneous Hubble Space Telescope-Spitzer Light Curves
• Brown Dwarf Photospheres are Patchy: A Hubble Space Telescope Near-infrared Spectroscopic Survey Finds Frequent Low-level Variability
• Characterizing 51 Eri b from 1-5 $\mu$m: a partly-cloudy exoplanet
• The 2MASS Wide-Field T Dwarf Search. IV Unting out T dwarfs with Methane Imaging
• The Viewing Geometry of Brown Dwarfs Influences Their Observed Colours and Variability Properties
• $ExtrasolarStorms$: Pressure-dependent Changes In Light Curve Phase In Brown Dwarfs From Simultaneous $Hubble$ and $Spitzer$ Observations
• Let the Great World Spin: Revealing the Stormy, Turbulent Nature of Young Giant Exoplanet Analogs with the Spitzer Space Telescope
• Rotation and variability of very low mass stars and brown dwarfs near Epsilon Ori
• Atmospheric circulation of brown dwarfs and directly imaged exoplanets driven by cloud radiative feedback: effects of rotation
• Simultaneous, Multi-Wavelength Variability Characterization of the Free-Floating Planetary Mass Object PSO J318.5-22
• Atmospheric circulation of brown dwarfs and directly imaged exoplanets driven by cloud radiative feedback: global and equatorial dynamics
• Cloud Atlas: Discovery of Patchy Clouds and High-amplitude Rotational Modulations In a Young, Extremely Red L-type Brown Dwarf
• Photometric variability of young brown dwarfs in the sigma Orionis open cluster
• Spitzer Variability Properties of Low-Gravity L Dwarfs
• Weather on Other Worlds. V. The Three Most Rapidly Rotating Ultra-Cool Dwarfs
• Spectral Variability of VHS J1256-1257 b from 1 to 5 $\mu$m
• A Search for Variability in Exoplanet Analogues and Low-Gravity Brown Dwarfs
• A mini-survey for variability in early L dwarfs
• Photometric variability of a young, low-mass brown dwarf
• Cloud Atlas: Rotational Spectral Modulations and potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C
• The Second Arecibo Search for 5 GHz Radio Flares from Ultracool Dwarfs
• Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star
• A search for photometric variability in the young T3.5 planetary-mass companion GU Psc b
• Characterizing The Cloud Decks of Luhman 16AB with Medium-Resolution Spectroscopic Monitoring
• Revealing the Vertical Cloud Structure of a young low-mass Brown Dwarf, an analog to the beta-Pictoris b directly-imaged exoplanet, through Keck I/MOSFIRE spectro-photometric variability
• Modeling Polarization Signals from Cloudy Brown Dwarfs: Luhman 16 A and B in Three Dimensions
• Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010
• Weather on Other Worlds. VI. Optical Spectrophotometry of Luhman 16B Reveals Large-amplitude Variations in the Alkali Lines

Cited by in corpus (3)

• Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry
• Exploring the directly imaged HD 1160 system through spectroscopic characterization and high-cadence variability monitoring
• Informed systematic method to identify variable mid and late-T dwarfs