Preprint article · Journal article
TOI-1749: an M dwarf with a Trio of Planets including a Near-resonant Pair
The University of Tokyo1
University of La Laguna2
Leiden University3
ESTEC4
Kyoto University5
German Aerospace Center6
National Institutes of Natural Sciences - AstroBiology Center7
Academia Sinica Taiwan8
Chinese Academy of Sciences9
Albanyà Astronomical Observatory10
George Mason University11
Chalmers University of Technology12
National Space Institute13
University of California at Santa Cruz14
Massachusetts Institute of Technology15
Astrophysics and Atmospheric Physics, National Space Institute, Technical University of Denmark16
National Space Institute, Technical University of Denmark17
Office for Study Programmes and Student Affairs, Administration, Technical University of Denmark18
Harvard-Smithsonian Center for Astrophysics19
Wesleyan University20
Princeton University21
Las Cumbres Observatory Global Telescope Network, Inc.22
SETI Institute23
CSIC-INTA - Astrobiology Center24
NASA Ames Research Center25
Instituto de Astrofísica de Canarias26
National Astronomical Observatory of Japan27
Vanderbilt University28
California Institute of Technology29
...and 19 moreWe report the discovery of one super-Earth- (TOI-1749b) and two sub-Neptune-sized planets (TOI-1749c and TOI-1749d) transiting an early M dwarf at a distance of 100 pc, which were first identified as planetary candidates using data from the TESS photometric survey. We have followed up this system from the ground by means of multiband transit photometry, adaptive optics imaging, and low-resolution spectroscopy, from which we have validated the planetary nature of the candidates.
We find that TOI-1749b, c, and d have orbital periods of 2.39, 4.49, and 9.05 days, and radii of 1.4, 2.1, and 2.5 R⊕, respectively. We also place 95% confidence upper limits on the masses of 57, 14, and 15 M⊕ for TOI-1749b, c, and d, respectively, from transit timing variations. The periods, sizes, and tentative masses of these planets are in line with a scenario in which all three planets initially had a hydrogen envelope on top of a rocky core, and only the envelope of the innermost planet has been stripped away by photoevaporation and/or core-powered mass-loss mechanisms.
These planets are similar to other planetary trios found around M dwarfs, such as TOI-175b,c,d and TOI-270b,c,d, in the sense that the outer pair has a period ratio within 1% of 2. Such a characteristic orbital configuration, in which an additional planet is located interior to a near 2:1 period-ratio pair, is relatively rare around FGK dwarfs.
