A Unified Spectroscopic and Photometric Model to Infer Surface Inhomogeneity: Application to Luhman 16B
arXiv:2206.01770 · doi:10.3847/1538-4357/ac75b9
Abstract
Extremely large telescopes (ELTs) provide an opportunity to observe surface inhomogeneities for ultracool objects including M dwarfs, brown dwarfs (BDs), and gas giant planets via Doppler imaging and spectro-photometry techniques. These inhomogeneities can be caused by star spots, clouds, and vortices. Star spots and associated stellar flares play a significant role in habitability, either stifling life or catalyzing abiogenesis depending on the emission frequency, magnitude, and orientation. Clouds and vortices may be the source of spectral and photometric variability observed at the L/T transition of BDs and are expected in gas giant exoplanets. We develop a versatile analytical framework to model and infer surface inhomogeneities which can be applied to both spectroscopic and photometric data. This model is validated against a slew of numerical simulations. Using archival spectroscopic and photometric data, we infer star spot parameters (location, size, and contrast) and generate global surface maps for Luhman 16B (an early T dwarf and one of our solar system's nearest neighbors at a distance of approximately 2 pc). We confirm previous findings that Luhman 16B's atmosphere is inhomogeneous with time-varying features. In addition, we provide tentative evidence of longer timescale atmospheric structures such as dark equatorial and bright mid-latitude to polar spots. These findings are discussed in the context of atmospheric circulation and dynamics for ultracool dwarfs. Our analytical model will be valuable in assessing the feasibility of using ELTs to study surface inhomogeneities of gas giant exoplanets and other ultracool objects.
23 pages, 10 figures, 1 table. Accepted for publication in The Astrophysical Journal
References in corpus (40)
- Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere
- A Re-appraisal of the Habitability of Planets Around M Dwarf Stars
- Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs
- Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e
- Strong Brightness Variations Signal Cloudy-to-Clear Transition of Brown Dwarfs
- Ammonia as a tracer of chemical equilibrium in the T7.5 dwarf Gliese 570D
- Simultaneous Detection of Water, Methane and Carbon Monoxide in the Atmosphere of Exoplanet HR8799b
- The CARMENES search for exoplanets around M dwarfs -- Planet occurrence rates from a subsample of 71 stars
- Vertical Atmospheric Structure in a Variable Brown Dwarf: Pressure-dependent Phase Shifts in Simultaneous Hubble Space Telescope-Spitzer Light Curves
- Atmospheric Dynamics of Hot Giant Planets and Brown Dwarfs
- Physical and Spectral Characteristics of the T8 and Later-Type Dwarfs
- A Misaligned Prograde Orbit for Kepler-13 Ab via Doppler Tomography
- Atmospheric Circulation of Brown Dwarfs: Jets, Vortices, and Time Variability
- Cloud structure of the nearest brown dwarfs: Spectroscopic variability of Luhman 16AB from the Hubble Space Telescope
- 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
- Deep Thermal Infrared Imaging of HR 8799 bcde: New Atmospheric Constraints and Limits on a Fifth Planet
- Surprisingly different starspot distributions on the near equal-mass equal-rotation-rate stars in the M dwarf binary GJ 65 AB
- TESS Observations of the Luhman 16AB Brown Dwarf System: Rotational Periods, Lightcurve Evolution, and Zonal Circulation
- On the Chemical Abundance of HR 8799 and the Planet c
- Giant white-light flares on fully convective stars occur at high latitudes
- Cloud Atlas: Rotational Spectral Modulations and potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C
- Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star
- Cloud Atlas: High-Contrast Time-Resolved Observations of Planetary-Mass Companions
- Cloud Atlas: Weak color modulations due to rotation in the planetary-mass companion GU Psc b and 11 other brown dwarfs
- Detection of new strongly variable brown dwarfs in the L/T transition
- Jet Streams and Tracer Mixing in the Atmospheres of Brown Dwarfs and Isolated Young Giant Planets
- Individual, Model-Independent Masses of the Closest Known Brown Dwarf Binary to the Sun
- Ultracool Dwarfs Survey. VI. White light superflares observed on an L5 dwarf and flare rates of L dwarfs
- Hubble Space Telescope astrometry of the closest brown dwarf binary system -- I. Overview and improved orbit
- The T Tauri star V410 Tau in the eyes of SPIRou and TESS
- Cloud Atlas: Unraveling the vertical cloud structure with the time-series spectrophotometry of an unusually red brown dwarf
- Scaling K2. III. Comparable Planet Occurrence in the FGK Samples of Campaign 5 and Kepler
- KELT-9 as an eclipsing double-lined spectroscopic binary: a unique and self-consistent solution to the system
- Cloud-convection feedback in brown dwarfs atmosphere
- 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
- Magnetic field and activity phenomena of the K2 dwarf V471 Tau
- Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010
- Time-Resolved High Spectral Resolution Observation of 2MASSW J0746425+200032AB
- Weather on Other Worlds. VI. Optical Spectrophotometry of Luhman 16B Reveals Large-amplitude Variations in the Alkali Lines
Cited by in corpus (5)
- Roaring Storms in the Planetary-Mass Companion VHS 1256-1257 b: Hubble Space Telescope Multi-epoch Monitoring Reveals Vigorous Evolution in an Ultra-cool Atmosphere
- Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry
- Global weather map reveals persistent top-of-atmosphere features on the nearest brown dwarfs
- Mapping the Skies of Ultracool Worlds: Detecting Storms and Spots with Extremely Large Telescopes
- Mapping atmospheric features of the planetary-mass brown dwarf SIMP 0136 with JWST NIRISS