- 1University of Bern, Center for Space and Habitability, Physics, Switzerland (francis.zong@unibe.ch)
- *A full list of authors appears at the end of the abstract
Context. The population of rocky exoplanets is abundant, and cool stars such as M dwarfs provide a unique
opportunity to detect these objects, which could have implications for the study of astrobiology. Both theoretical models
and observations have shown that these tend to lie in the host stars’ habitable zone. The proximity of such planets
to their host star also provides an opportunity for atmospheric studies.
SAINT-EX (Searching And characterisINg Transiting EXoplanets) consists of a one-meter telescope optimized to
obtain high-precision light curves of transiting planets orbiting ultracool stars. The two main objectives of SAINT-
EX are: -The search for terrestrial exoplanets orbiting ultra-cool stars, and -To give ground-based support to the
ESA CHEOPS mission. Another outcome of this mission is the characterization of orbital periods and stellar
variability in brown dwarfs and ultra-cool stars.
Aims. TOI4616, a system with a planet of size 1.22R and an orbital period of 1.554 days, was detected by the
NASA TESS mission and later characterized with the SAINT-EX telescope. We study this system to characterize
the properties of the planet and its host star and use transit photometry to constrain critical parameters of the planet,
such as its mass and orbital dynamics. Employing a series of aperture and PSF photometry methods to determine
the crowding metric and the flux fraction to compute an accurate transit depth obtained from the SAINT-EX light
curves and constrain the necessary planetary parameters.
Methods. We make use of the Monte-Carlo technique to compare the transit depth with the data from SAINT-EX
and those from the TESS
Results. The validation of an orbital period of 1.554 days reinforces our understanding of rocky exoplanets around
low-mass stars. We expect TOI4616 to be a rocky exoplanet with the possibility of hosting an atmosphere. Transmission spectroscopy analysis might offer insights into the exoplanet’s atmosphere, revealing potential
molecular constituents. Investigating the planet’s stability in this system would reveal potential interactions with
other bodies and the system’s long-term stability.
F. Zong Lang, B.O. Demory, Yanick Schmidt, Y. Gómez Maqueo Chew, N.N. Urs, K. G., Mathilde Timmermans, Erik Mayer V., Stassun, Amaury Triaud, Artem Budanov, Benjamin Rackham, Karen Collins, Cristilyn, Khalid B., Watkins, Elsa Ducrot, and Ils Plauchu Frayn
How to cite: Zong Lang, F. and Demory, B.-O. and the TOI4616: Constraining The Parameters of an Earth-Sized Exoplanet Orbiting an M3 Star, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–12 Sep 2025, EPSC-DPS2025-857, https://doi.org/10.5194/epsc-dps2025-857, 2025.
