Research

Time-resolved Retrievals

Brown dwarfs and exoplanets exhibit complex atmospheric phenomena, including clouds, storms, auroral activity, and chemical inhomogeneities, which can drive strong spectral variability. The advent of JWST time-series spectroscopy has opened a new window into studying these processes in unprecedented detail.

To exploit these observations, I am developing Tempawral, a data-driven time-resolved atmospheric retrieval framework based on eigen-spectra inversion. This approach enables robust and generalizable characterization of atmospheric variability, allowing us to identify the physical mechanisms responsible for observed spectral changes.

Brown Dwarf Variability

I analyze JWST/NIRISS-SOSS time-series spectroscopy of variable brown dwarfs, including the auroral objects SIMP J0136 and LSR J1835+3259. By performing time-resolved atmospheric retrievals, I investigate the relative roles of clouds, chemistry, temperature structure, and auroral processes in driving rotational variability.

These studies provide new constraints on the atmospheric dynamics and physical processes operating in substellar atmospheres.

Spectropolarimetry of Brown Dwarfs

Polarized thermal emission provides a complementary probe of atmospheric structure that is inaccessible through flux spectroscopy alone.

My work explores how cloud properties, atmospheric temperature gradients, and scattering processes shape the spectropolarimetric signatures of brown dwarfs. Broadband polarization is primarily sensitive to cloud optical thickness, while characteristic wavelength-dependent features can constrain cloud particle sizes. Polarization signals within molecular absorption bands can additionally probe local temperature gradients near the photosphere.

Future near-infrared spectropolarimeters with moderate spectral resolution and sensitivities below 10⁻⁵ could detect these signatures and help break degeneracies present in traditional flux-only atmospheric retrievals.

Detecting Surface Biosignatures on Earth-like Exoplanets

Direct-imaging observations of Earth-like exoplanets contain information about both atmospheric composition and surface properties.

I simulate time-series observations of Earth analogues using future direct-imaging mission concepts such as the Habitable Worlds Observatory (HWO). By combining atmospheric retrieval techniques with reflected-light spectroscopy, I investigate our ability to constrain surface albedo, cloud properties, and potential biosignatures.

Our studies show that combining ultraviolet and visible-wavelength spectra can significantly improve constraints on wavelength-dependent surface reflectance and water-cloud properties, providing a pathway toward characterizing potentially habitable worlds.