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Hi there :)
I'm interested in exploring the physical (and chemical) processes that drive the composition and evolution of rocky material in the inner 10 AU of protoplanetary disks during their lifetime. Specifically, I utilize observations across the electromagnetic spectrum, both from ground-based and space telescopes, and theoretical models to investigate how rocky material is transported and processed, thereby setting the fundamental building blocks of all planets.
You can find the full list of my publications on ADS
Artists concept of a protoplanetary disk.
Using the accretion flows to probe dust evolution in T Tauri stars.
Using the accretion flows to probe dust evolution in T Tauri stars.
T Tauri Stars are young (1-10Myr) low-mass stars surrounded by their protoplanetary disk. The star accretes its mass from the inner gas disk after all dust particles are sublimated at the dust wall, through magnetospheric accretion. In this process, the stellar magnetic field cuts off the disk at a few stellar radii, and matter from the disk free-falls onto the star along the field lines, in the so-called accretion flows, carrying the elements that were not trapped or lost in the outer parts of the disk.
My work uses the broad emission lines that characterize the spectra of young stars and are formed in the accretion flows to measure the chemical composition of the inner disk. With this method, we can access the bulk of the material without relying on models for the disk and complicated elementary distributions. Here are some fun results I've found:
Ca depletion in line profiles!
Ca depletion in line profiles!
The figure above shows emission lines of two T Tauri stars from the Chameleon I star-forming cloud with similar physical conditions.
Their similarities are reflected in the Hα line (which traces the gas), both having comparable fluxes and strong profiles with high-velocity wings. However, T28 shows much narrower and weaker Ca II lines. Since the densities and temperatures of the magnetospheric flows of T28 are high (as shown by Hα), the observed weakness of the Ca II lines strongly suggests an absence of Ca in the accretion flows and therefore in the inner gas disk.
Micolta et al. 2023, ApJ, 953, 177 (see full paper here)
Ca depletion is common and changes with Age!
Ca depletion is common and changes with Age!
The figure above shows the Ca abundance estimate using the Ca II lines for T Tauri Stars of three star-forming regions. A tentative trend with age can be seen, where all the older disks show high levels of depletion, but the younger disks are found everywhere.
Mg depletion and evidence for effects of sublimation fronts in rocky material!
Mg depletion and evidence for effects of sublimation fronts in rocky material!
The figure above shows the joint and marginal distributions of Ca and Mg abundance for BP Tau.
The level of refractory depletion found in BP Tau can only be explained by dust-related processes in the disk. The difference between the two elements hints at dust drift effects, with the different sublimation fronts affecting the Ca (1600K) and Mg (1400K) reservoirs differently.
Acepted in ApJ, in press. See full paper preprint here.
Connecting the accretion flows with the disk using the SED.
Connecting the accretion flows with the disk using the SED.
I used BP Tau as a test case, aiming to connect the results obtained from the accretion flows with the dust information the Spectral Energy Distribution (SED) offers. Modeling of the accretion lines found depletion of Ca in the accretion flows (and innermost gas disk). Detailed SED modeling revealed a small cavity inside 10 AU, consistent with sub-mm imaging, and a significant decrease of the Mg-to-Fe ratio with decreasing radius, consistent with the accretion flows results.
Acepted in ApJ, in press. See full paper preprint here.
Spectral energy distribution of BP Tau. In black, observational data includes photometry and an Spitzer/IRS spectra. Color lines reflect the different parts of the models.
Schematic view of the of BP Tau. Connecting the strucutre and dust composition obtained from SED with the results of he accretion flows
My next steps will involve applying this type of multi-wavelength analysis to more sources!
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