My work on Prof. Edwin Bergin's group focuses on the study of the chemical content of protoplanetary disks, which plays a crucial role in determining the composition of planets forming within them. We use the carbon to oxygen ratio (C/O) as a tracer of disk chemistry since variations in this ratio can inform us about the types of molecules present in the disk. Understanding the C/O ratio is vital for unraveling the complex processes involved in planetary formation and composition. I'm currently part of the JDISCS collaboration, which uses MIRI observations from JWST to understand the evolution of the chemistry in inner protoplanetary disks.

In my latest paper, Colmenares et al. (2024b), we analyzed MIRI-MRS observations of DoAr 33, a T Tauri star with a hydrocarbon-rich disk. Through detailed analysis using LTE slab models, we retrieved the temperature, column density, and emitting area of nine detected species, then applied thermochemical models to explore carbon and oxygen distributions across the inner disk. We found the observed column densities and emitting temperature of C₂H₂ best matched models with carbon enrichment, specifically with C/O ratios of 2–4 inside the 500 K dust sublimation line. This suggests that the carbon-rich chemistry originates from carbon grain sublimation near the soot line, consistent with crystalline silicate detections indicating dust processing. 

We propose that this sustained hydrocarbon-rich chemistry around a solar-mass star results from the central star's unusually low accretion rate, which extends the radial mixing timescale, allowing carbon-rich chemistry from grain destruction to persist, similar to very low mass stars. This can also be extended to explain the carbon-poor rich of higher mass T Tauris, that accrete the carbon-rich gas before it can be mixed into the surface layers and observed with JWST. 

Solar System meteorites exhibit a fundamental isotopic dichotomy between non-carbonaceous (NC) and carbonaceous (CC) groups. The existence of this dichotomy hints at two separate reservoirs from which planets could accrete material during the formation of the Solar System. In Colmenares et al. (2024a), we studied how an accretion outburst can set a thermal gradient in the protoplanetary disk and impart an isotopic signature.  We modeled how these two distinct reservoirs evolve, and found that the combination of viscous mixing and radial drift of the pebble populations is consistent with isotopic signatures in the current-day meteorites, specifically in supernovae-origin isotopes like 54Cr, 30Si,48Ca, among others.  This contrasts the idea that Jupiter formed in-situ and served as a barrier between the two reservoirs. 

Credit: NASA/JPL-Caltech

Magnetospheric accretion is a key process in the formation of T Tauri stars, where material from the surrounding disk accretes onto the star's surface along magnetic field lines. It influences the stellar mass and rotation, but also plays a crucial role in the evolution of its protoplanetary disk. The study of magnetospheric accretion is essential for comprehending the interplay between stellar accretion and the development of planetary systems around young stars. During my undergrad, I studied the Hydrogen lines of accreting stars from X-shooter spectra to find a relation between the flux and the geometry of the magnetosphere. Most recently, Micolta et al. (2022) found that refractory abundances measured from accretion flows might reflect substructures in the protoplanetary disk.