TOI-1452 b: SPIRou and TESS Reveal a Super-Earth in a Temperate Orbit Transiting an M4 Dwarf

September 2022 • 2022AJ....164...96C

Authors • Cadieux, Charles • Doyon, René • Plotnykov, Mykhaylo • Hébrard, Guillaume • Jahandar, Farbod • Artigau, Étienne • Valencia, Diana • Cook, Neil J. • Martioli, Eder • Vandal, Thomas • Donati, Jean-François • Cloutier, Ryan • Narita, Norio • Fukui, Akihiko • Hirano, Teruyuki • Bouchy, François • Cowan, Nicolas B. • Gonzales, Erica J. • Ciardi, David R. • Stassun, Keivan G. • Arnold, Luc • Benneke, Björn • Boisse, Isabelle • Bonfils, Xavier • Carmona, Andrés • Cortés-Zuleta, Pía • Delfosse, Xavier • Forveille, Thierry • Fouqué, Pascal • Gomes da Silva, João • Jenkins, Jon M. • Kiefer, Flavien • Kóspál, Ágnes • Lafrenière, David • Martins, Jorge H. C. • Moutou, Claire • do Nascimento, J. -D. • Ould-Elhkim, Merwan • Pelletier, Stefan • Twicken, Joseph D. • Bouma, Luke G. • Cartwright, Scott • Darveau-Bernier, Antoine • Grankin, Konstantin • Ikoma, Masahiro • Kagetani, Taiki • Kawauchi, Kiyoe • Kodama, Takanori • Kotani, Takayuki • Latham, David W. • Menou, Kristen • Ricker, George • Seager, Sara • Tamura, Motohide • Vanderspek, Roland • Watanabe, Noriharu

Abstract • Exploring the properties of exoplanets near or inside the radius valley provides insight on the transition from the rocky super-Earths to the larger, hydrogen-rich atmosphere mini-Neptunes. Here, we report the discovery of TOI-1452b, a transiting super-Earth (R p = 1.67 ± 0.07 R ) in an 11.1 day temperate orbit (T eq = 326 ± 7 K) around the primary member (H = 10.0, T eff = 3185 ± 50 K) of a nearby visual-binary M dwarf. The transits were first detected by the Transiting Exoplanet Survey Satellite, then successfully isolated between the two 3.″2 companions with ground-based photometry from the Observatoire du Mont-Mégantic and MuSCAT3. The planetary nature of TOI-1452b was established through high-precision velocimetry with the near-infrared SPIRou spectropolarimeter as part of the ongoing SPIRou Legacy Survey. The measured planetary mass (4.8 ± 1.3 M ) and inferred bulk density ( ${5.6}_{-1.6}^{+1.8}$ g cm-3) is suggestive of a rocky core surrounded by a volatile-rich envelope. More quantitatively, the mass and radius of TOI-1452b, combined with the stellar abundance of refractory elements (Fe, Mg, and Si) measured by SPIRou, is consistent with a core-mass fraction of 18% ± 6% and a water-mass fraction of ${22}_{-13}^{+21}$ %. The water world candidate TOI-1452b is a prime target for future atmospheric characterization with JWST, featuring a transmission spectroscopy metric similar to other well-known temperate small planets such as LHS 1140b and K2-18 b. The system is located near Webb's northern continuous viewing zone, implying that is can be followed at almost any moment of the year.


IPAC Authors


David Ciardi

Senior Scientist