Research

Studying the Water-Pebble Dynamics Connection: Linking Water Observations in the Inner Disk and Pebble Dynamics in the Outer Disk

While ALMA observations access the outer cold disk and provide the best way to study pebble dynamics in the >10 AU region, the innermost region is invisible to ALMA. IR spectra are instead able to provide a wealth of information about the various volatiles residing here. These volatiles are usually locked up in icy bodies in the outer disk and are carried inward by drifting particles. Some mass of volatiles sublimate off these pebbles once pebbles travel inward of the snow line region. That is, if pebbles are not obstructed on their way to the inner disk. We argue that water delivered to the inner disk will carry a signature of the presence of substructure in the outer disk that may block drifting pebbles, as well as some imprint of the efficiency of planetesimal formation. Motivated by the observational correlations found by Najita+2013, Banzatti+2020, we conduct a detailed modeling study where we try to understand what effect structure in the outer disk has on the water enrichment in the inner disk.

Check out the corresponding publications under Publications:

  1. Banzatti et al. 2023b (JWST-MIRI Spectra show likely evidence of pebble drift in disks)
  2. Kalyaan et al. 2023 (Modeling work II)
  3. Kalyaan et al. 2021 (Modeling work I)

Collaborators: Andrea Banzatti, Paola Pinilla, Sebastiaan Krijt, Whittney Easterwood (undergraduate mentee, now phD student at U. Idaho), Giovanni Rosotti, Gijs Mulders, Michiel Lambrechts, Feng Long, Gregory Herczeg

(Image: Banzatti+2020 and Kalyaan+2023)

Studying The (Pre)Transitional Disk of our Solar Nebula from Meteoritic Constraints

Work by Kruijer +2017 (and earlier works before them) has revolutionized our understanding of the dynamics in the solar nebula; just as we were seeing evidence of rapid planet formation in other disks, we are seeing the same in our own solar disk, by the evidence of the creation of two separate isotopic reservoirs, one in the inner disk and one in the outer disk, with the separation likely caused by the formation of a proto-jupiter. Our solar nebula was very like a transitional disk with a planet-created gap by 1Myr. It was likely that a variety of small solid bodies that carried many chemical species (refractory material that made up calcium-aluminum inclusions (CAIs) and bulk volatiles) around, freely transporting material between the inner and outer region of the nebula before proto-jupiter formed and stopped permitting this free mass flow.

Check out Desch, Kalyaan & Alexander (2018) (under Publications) to read more about our work.

Currently, we are interested in exploring what might have been the bulk water content across a (pre)transitional solar nebula.
Building on our previous studies, Steve Desch and I are working on this question right now!

Structure, Evolution and Water Distribution in Protoplanetary Disks: Beyond the standard alpha disk

How does a typical protoplanetary disk evolve with time, with the interplay of accretionary (winds) and dispersal processes (winds, photoevaporation, planet formation)?

The knowledge of the alpha parameter (i.e., the radial transport and mixing efficiency) across the radial extent of the disk is crucial. In Kalyaan+2015, we found that the alpha(r) profile can significantly change the structure and evolution of the disk. This has an important effect on the distribution of the chemical tracers that are entrained in the bulk gas as well, as we investigate in Kalyaan & Desch (2019). We find that water can even be a proxy for determining the alpha(r) profile in disks and perhaps even the mechanism of angular momentum transport at play.

We investigated these questions with the help of a 1D/1.5D disk evolution code. See the following papers under Publications:

  1. Kalyaan & Desch (2019)
  2. Kalyaan et al. (2015)

Collaborators: Steve Desch
(Image: ALMA Partnership et al. 2015)

Numerical Model/Code

Most of the research above use a standard 1D disk evolution model written in Fortran. This original code was developed by Steve Desch. I have since further developed the code in different ways: 1) implementing non-uniform alpha viscosity (Kalyaan+2015), 2) snow line modeling, implementing radial transport of volatiles, and solids (Kalyaan & Desch 2019), 3) disk structure in the form of gaps (Desch et al. 2018, Kalyaan+2021, 2023) and 4) dust evolution (two population model of Birnstiel et al. 2012) (Kalyaan+2023) and 5) planetesimal formation. (Kalyaan+2023).

Soon to come on GitHub.

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