Jenny Calahan

I am an Origins of Life Fellow at the Center for Astrophysics. I primarily use thermo-chemical models to better understand the chemical and physical environment within protoplanetary disks. My models are all constrained by observations, mainly ALMA and JWST. I am generally interested in 'typical' planet formation, including tracing the water reservoir, seeing how clustered environments impact the chemistry of planet formation, and observations of FUOr which expose the volatile chemical reservoir.

You can contact me at jenny.calahan[at]cfa.harvard.edu

Five Square Images

Image of Jenny with arms crossed, hair down

Image of Jenny with walking poles, infront of the cathedral in Santiago de Compostela

Image of Jenny and her brother, holding bikes above their head after biking across Iowa

Image of Jenny holding two toy molecules: CH3CN and CH4

Thermo-chemical Models for Specific Disks

I created very well constrained models for the disks TW Hya and HD 163296 using a 2D-thermochemical model, and reproducing multiple resolved ALMA observations. These produce well constrained 2D temperature profiles of each disk, allow for estimates of disk mass, and are used to futher understand the chemical environment in these disks.

Both papers below have 2D disk models that are publically available

Resolving the Gaseous Thermal Profile of the TW Hya Disk

Determining the 2D Thermal Structure of the HD 163296 Disk

Evolved Disks Contain UV-Enriched, Carbon-Rich Chemistry

Using my thermo-chemical models of TW Hya and HD 163296, I am also able to reproduce observations of the carbon-rich species CH3CN , HCN, and HC3N. I argue the only way to reproduce this and all other previous observations are by evoking a UV-enriched radiation field due to the evoultion of small dust.

UV-driven chemistry as a signpost of late-stage planet formation

Probing the Water Resevior in the Terrestrial Planet-Forming Region

Water is unique amongst molecule for many reasons, including the way it impacts the transfer of UV photons. Once water is optically thick it will block UV photons across a wide range of wavelengths. We implemented this water self-shielding in the thermo-chemical code DALI, and I found that it enhanced the H2-18O abundance relative to H2-16O. I was then able to identify the best transitions for discovering H2-18O in JWST spectra.

Oxygen-18 Isotope Anomalies in H2-18O Infrared Emission and Meteorites

NOEMA Chemical Survey of FU Ori Objects

FUOr objects are young stellar objects that undergo extreme outbursts due to a rapid increase in accretion from the disk onto the star. This offers a 'hack' to probe the chemistry of planet formation in the gas-phase, as many volitles will sublimate from the ice-phase into the gas. I observed 5 outbursting sources with NOEMA and find that each of the disks/inner envelope contain high masses, and I detected COMs, water, and multiple sulfur-bearing species in the source V1057 Cyg.

High Mass Inner Regions Found in Five Outbursting Sourcess

A Chemical Inventory of V1057 Cyg

Outreach & DEI Activities

I am enthusiastic about sharing my passion for astronomy, and take time to inspire future generations to persue a career in STEM. I also know the only way to keep people in this field is to make astronomy accessible to all, regardless of background, resources, and opportunity. Thus, I spend a significant amount of my time in fostering community, with a focus on promoting Diversity, Equity, Inclusion, and Accessibility.

Deputy of CfA's EDIB Committee

The Center for Astrophysics has a committee on Equity, Diversity, Inclusion, and Belonging with representatives from all departments and career stages. Since I started on the committee in Fall of 2023, I have be one of two deupties, aiding in committee organiziation and dissemination of information.

LGBTQ+ Identity Group Leader

I initiated the formation of Identity Groups at the CfA, and lead the LGBTQ+ group. People who identify as LGBTQ+ are all welcome to join us for a time of networking and building community. I have procurred funding so that 10+ attendees will recive free food and coffee.

SGMA Member

I am a member of the AAS committee on Sexual and Gender-Minorities in Astronomy (SGMA) since Fall of 2023. As a member, I am creating a resource of LGBTQ+ identifying individuals who are willing to give science talks at other institutions.

AMP-UP Leader

The Astronomy Mentorship Program for Upcoming Postdocs (AMP-UP) has been acitve for three years, and I joined the leadership committee in Fall 2024 after serving as a mentor in the 2023-2024 job season. As a leader of the program, I aided in mentor-mentee pairing, and ran workshops on aspects of the postdoc application process.

Postdoc Council Member

I am a member of the CfA's Postdoc Committee, which consists of postdocs from each division. As a member, I have organizinged networking opportunities for the 100+ postdocs at the CfA and represent postdoc needs when communicating with department leaders.

Miscellaneous

I have a reputation for being very knowledgable on how to make processes more equitable and accessible. I have been called to help write a best hiring practices document for the CfA, I helped organize a JWST peer-review process, and write a code of conduct for journal clubs and collaborations.