Exoplanet Spectroscopy & Telluric Corrections

Overview

Cornell University Research in Astrophysics and Planetary Science REU + SUNY New Paltz Physics Senior Project & Honors Thesis

Mentors: Dr. Adam Langeveld, Department of Astrophysics and Planetary Science, Cornell University (P.I. Prof. Ray Jayawardhana);

Dr. Amy Bartholomew, Chair of Physics & Astronomy SUNY New Paltz ;

Dr. Patricia Sullivan, Director of Honors Program SUNY New Paltz

Programs: Astrophysics and Planetary Science REU (Cornell University 2023)

Physics Senior Project & Honors Thesis (SUNY New Paltz 2024)

Conference: American Astronomical Society (AAS) - W24

Poster Award: Chambliss Astronomy Achievement Award

Presentations: Cornell University Summer Research Symposium (Talk + Poster)

Summer Research Presentations SUNY New Paltz (Talk)

Topics: Spectroscopy, telluric contamination, telluric corrections, exoplanetary atmospheres

Conclusions determine ideal airmass for observation proposals & indicate that some data in contaminated regions may be salvageable.

Highlights

Paper

Click to view full paper:

Poster & Award

Click to view on AAS website:

Process Summary

Cornell REU: Astrophysics & Planetary Science

Cornell University Student Research Symposium, August 2024

Assessing Telluric Corrections Contamination

Telluric contamination, or spectral contamination from the Earth's atmosphere, is inherent to high-resolution ground-based spectroscopy and distorts spectral signals from all celestial bodies. This interference is not uniform across the spectra and has a dependence on atmospheric parameters such as airmass, pressure, humidity, and temperature, which alter the intensity in the molecular composition of the telluric lines. Because these atmospheric features often vary over the course of observations, it is difficult to accurately remove the telluric lines from the spectra. This project assessed the quality of corrections.

Coding Language: Python (numpy, scipy, matplotlib, etc.)

An example of an atmospheric parameter graph demonstrating airmass and its parabolic nature over the course of the observation

Atmospheric Parameters

Extracted atmospheric parameters and observation related data from FITS file headers. These variables included temperature, pressure, humidity, airmass, and the signal to noise ratio.

Telluric Corrections using Molecfit. Demonstrates the model, data, and corrected flux.

Isolating Peaks and Defining a Data Set

Performed molecfit corrections (dividing out a molecular model of the Earth's atmosphere from the observations to retrieve a corrected flux). Then, individual telluric lines and groups of telluric lines were isolated based on absorption depth ranges as well as wavelength regions.

Statistically Assessing Quality

Using the Reduced Chi-Square and Residual Sum of Squares statistical assessment methods, we could compare the accuracy of the corrections done based on the peaks previously isolated. These also allowed us to compare correction quality and atmospheric parameters.

Summer Results

We found telluric depth ranges to have similar airmass dependency and that shallow tellurics correct better than deep tellurics. We also found that the Oxygen and Water molecular bands correct similarly. For ideal corrections, we determined that observations should be made at airmasses below 1.07.

However, this project does not end here! I was determined to investigate deeper into the subject and decipher my results and ideas. Therefore, I continued with my Honors Thesis and Physics Senior Project upon my return to my home institution.

Physics Senior Project & Honors Thesis

Fall 2024

During the Fall semester, I presented my research at SUNY New Paltz in a Summer Research Talk. While continuing to work on the code, data, conclusions, and paper, I also got approved for the American Astronomical Society's poster session.

Spring 2024

During the Spring semester, I continued conducting the research, working to narrow down the influence of airmass as well as distinguish the absorption quantity cutoff for ideal corrections. I was published through my Honors Thesis and completed my work on this project.

Communicating Results

Cornell REU: Astrophysics and Planetary Science

Cornell University Student Research Symposium, August 2024

I presented a talk and poster at the Cornell Student Research Symposium to conclude the REU experience that summer. To the left is a photo from the poster presentations. Above is the REU student cohort (I am pictured fourth from the left) with some non-REU Cornell students as well as the REU coordinator Patricia E. Fernandez de Castro Martinez (third from the right) and the program directors Dr. Alex Hayes (far left) and Dr. Britney Schmidt (far right)

Presentation Slides from the Symposium (August 2024)

American Astronomical Society

During the winter, I presented a poster at the AAS conference in New Orleans, LA. There, I was awarded the prestigious Chambliss Award, the highest award achievable for poster presentations.