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.
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Figure 1 in Rackham et al. 2018
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.
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.
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Each marker is one exposure of a target, solid curves are highest altitude / lowest airmass during the night, and vertical dashed lines correspond to times of HST visits
I built a photometry and data management pipeline with Shell and Astropy and obtaied prelimary photometry on the eight targets.
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Prelimary light curves of eight SPACE Program host stars
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.
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RMS of photometry for all stars in the field of TOI-1759, which is indicated by the star symbol. This provide information about the instrument precision.
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.
I would love to hear your questions, comments, and suggestions! My email address is: qtian [at] jhu.edu.