I use a Markov Chain Monte Carlo (MCMC) forward-modeling method to model the high-resolution spectra and extract precise radial and projected rotational velocities, as well as surface temperatures and surface gravities for hundreds of nearby ultracool dwarfs.
Space motions of celestial objects tell us how their formation history and evolution. Using a forward-modeling method, I measured previse radial and projected rotational velocities of 37 T dwarfs. I compiled a local 3D kinematics sample of 172 late-M, L, and T dwarfs and found kinematic evidence of the stellar and substellar boundary.
Binaries are a direct product of star formation. They provide measurements of mass, separation, orbital period and eccentricity which can be used to constrain the star formation models. Using the precise radial velocity (RV) using the forward-modeling method, I found the first RV-verified T dwarfs J1106+2754 and J2126+7617 and the shortest-orbital-period ultracool dwarf binary LP 413-53AB. I also contributed to RV measurements of a young ultracool dwarf (likely) triple system DENIS J0630+1840.
The rotation of ultracool dwarfs tells us their angular momentum evolution. Stellar and substellar objects experience different phases of angular momentum evolution, which can be constrained using their rotational period (through photometric light curves) and projected rotational velocities (vsini) through high-resolution spectroscopy.
More recently, I am working on a high-resolution spectroscopic survey to extract the gas giant planet using the Keck Planet Imager and Characterizer (KPIC; Mawet et al. 2017). The rotation (Wang et al. 2021) and abundances (Xuan et al. 2022) of gas exoplanets can provide us with their formation and evolution. Stay tuned for our future updates!