If you are familiar with exoplanet transmission spectroscopy, you might have heard of the Transit Light Source Effect (Rackham et al. 2018, 2019). The idea is that stellar activity features, like starspots, faculae, and flares, alter the star's spectrum and introduce noise into the derived planetary atmosphere spectrum.

The SPACE Program, or the Sub-Neptune Planetary Atmosphere Characterization Experiment, is a multicycle HST program studying eight sub-Neptunes. It is led by PI Laura Kreidberg and co-PI Drake Deming.

To address the potential issue stellar activity might cause in the SPACE Program, I started monitoring the exoplanet hosts in photometry with Wesleyan University's 0.6-m automated telescope, advised by Prof. Seth Redfield. From late 2022 to April 2024, we gathered hundreds of GB of data.

I built a photometry and data management pipeline with Shell and Astropy and obtaied prelimary photometry on the eight targets.

In the coming months, I will refine the photometry. My hope is to recover rotational signals from the M dwarfs in the sample and provide a statistical measure of stellar activity for the rest. Compared with TESS photometry, my project provides a longer baseline, smaller pixel scale, and coverage in four bands (BVRI), and therefore could be complenertary to exisiting stellar activity data on these stars.

In the meantime, I am writing a paper summarizing the study, while contributing to the SPACE Program's planetary atmosphere papers.

I would love to hear your questions, comments, and suggestions! My email address is: qtian [at] jhu.edu.