TOI-3984 A b and TOI-5293 A b: two temperate gas giants transiting mid-M dwarfs in wide binary systems

With a collaborator from Penn State University, we brought our little Nieves Observatory of the Soka University of America into its first published astrophysical paper. The project was to use our 0.3-meter telescope to confirm the detection of an extrasolar planet that was earlier detected by the satellite TESS. The light from the star is dimmed when the planet crosses in front of the star (or transits), and this allows measuring the size of the planet by comparing the radius of the planet with the star’s radius, which is derived from the fractional amount of light blocked during the transit. Our telescope was used remotely from PSU, and the data helps us learn more about the planets in these systems.

The paper was entitled “TOI-3984 A b and TOI-5293 A b: Two Temperate Gas Giants Transiting Mid-M Dwarfs in Wide Binary Systems” and was published in the Astronomical Journal in 2023. The paper confirms the existence of two gas giant exoplanets, TOI-3984 A b and TOI-5293 A b, orbiting M dwarf stars identified by TESS. These planets are notable for their relatively cool temperatures and their presence in wide binary systems, each with a significant stellar companion. The study utilizes a combination of TESS photometry, ground-based observations, speckle imaging, and high-precision radial velocity measurements to characterize the planets. TOI-3984 A b has a mass of approximately 0.14 Jupiter masses and an orbital period of 4.35 days, while TOI-5293 A b has a mass of 0.54 Jupiter masses and an orbital period of 2.93 days. The findings highlight the potential for these systems to provide insights into the formation and migration of gas giants around M dwarfs and their atmospheric compositions.

The light curve from the transit of the exoplanet, as taken with our Nieves Observatory at Soka University of America. the dip in the star’s brightness is caused by the planet transiting in front of the star, and the model (in blue) allows for the calculation of the size of the exoplanet.

This paper contributes significantly to our understanding of exoplanetary systems, particularly in the context of gas giants orbiting M dwarf stars. Traditionally, gas giants have been found around more massive stars, making these findings around M dwarfs relatively rare and valuable for comparative planetology. The study of TOI-3984 A b and TOI-5293 A b offers insights into the diversity of planetary systems and challenges existing models of planet formation and migration, especially in the less massive protoplanetary disks around M dwarfs. Additionally, the characterization of these planets expands our knowledge of temperate gas giants’ atmospheric properties and potential habitability. The methodologies employed in this paper, combining space-based and ground-based observations with high-precision spectroscopy, set a precedent for future studies of similar exoplanetary systems.

(note: this summary was made with the assistance of GPT 4o).