TOI-1468: A system of two transiting planets, a super-Earth and a mini-Neptune, on opposite sides of the radius valley

Chaturvedi, P.; Bluhm, P.; Nagel, E.; Hatzes, A. P.; Morello, G.; Brady, M.; Korth, J.; Molaverdikhani, K.; Kossakowski, D.; Caballero, J. A.; Guenther, E. W.; Pallé, E.; Espinoza, N.; Seifahrt, A.; Lodieu, N.; Cifuentes, C.; Furlan, E.; Amado, P. J.; Barclay, T.; Bean, J.; Béjar, V. J. S.; Bergond, G.; Boyle, A. W.; Ciardi, D.; Collins, K. A.; Collins, K. I.; Esparza-Borges, E.; Fukui, A.; Gnilka, C. L.; Goeke, R.; Guerra, P.; Henning, Th.; Herrero, E.; Howell, S. B.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kasper, D.; Kodama, T.; Latham, D. W.; López-González, M. J.; Luque, R.; Montes, D.; Morales, J. C.; Mori, M.; Murgas, F.; Narita, N.; Nowak, G.; Parviainen, H.; Passegger, V. M.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Rodriguez, E.; Rodríguez-López, C.; Schlecker, M.; Schwarz, R. P.; Schweitzer, A.; Seager, S.; Stefánsson, G.; Stockdale, C.; Tal-Or, L.; Twicken, J. D.; Vanaverbeke, S.; Wang, G.; Watanabe, D.; Winn, J. N.; Zechmeister, M.
Bibliographical reference

Astronomy and Astrophysics

Advertised on:
10
2022
Number of authors
70
IAC number of authors
10
Citations
14
Refereed citations
13
Description
We report the discovery and characterization of two small transiting planets orbiting the bright M3.0V star TOI-1468 (LSPM J0106+1913), whose transit signals were detected in the photometric time series in three sectors of the TESS mission. We confirm the planetary nature of both of them using precise radial velocity measurements from the CARMENES and MAROON-X spectrographs, and supplement them with ground-based transit photometry. A joint analysis of all these data reveals that the shorter-period planet, TOI-1468 b (Pb = 1.88 d), has a planetary mass of Mb = 3.21 ± 0.24M⊕ and a radius of Rb = 1.280−0.039+0.038 R⊕, resulting in a density of ρb = 8.39−0.92+1.05 g cm−3, which is consistent with a mostly rocky composition. For the outer planet, TOI-1468 c (Pc = 15.53 d), we derive a mass of Mc = 6.64−0.68+0.67 M⊕,aradius of Rc = 2.06 ± 0.04 R⊕, and a bulk density of ρc = 2.00−0.19+0.21 g cm−3, which corresponds to a rocky core composition with a H/He gas envelope. These planets are located on opposite sides of the radius valley, making our system an interesting discovery as there are only a handful of other systems with the same properties. This discovery can further help determine a more precise location of the radius valley for small planets around M dwarfs and, therefore, shed more light on planet formation and evolution scenarios.

Radial velocities and photometry are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/666/A155

Related projects
Discovery of a system of super-Earths orbiting the star HD 176986 with about 5.7 and 9.2 Earth masses.
Very Low Mass Stars, Brown Dwarfs and Planets
Our goal is to study the processes that lead to the formation of low mass stars, brown dwarfs and planets and to characterize the physical properties of these objects in various evolutionary stages. Low mass stars and brown dwarfs are likely the most numerous type of objects in our Galaxy but due to their low intrinsic luminosity they are not so
Rafael
Rebolo López
Projects' name image
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
Enric
Pallé Bago