An ultra-short-period transiting super-Earth orbiting the M3 dwarf TOI-1685

Abstract

Dynamical histories of planetary systems, as well as atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685 (2MASS J04342248+4302148). We confirm the planetary nature of the transit signal, which has a period of P_b=0.6691403+0.0000023-0.0000021 d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of M_b=3.78+/-0.63 M_Earth, a radius of R_b=1.70+/-0.07 R_Earth, which together result in a bulk density of rho_b=4.21+0.95-0.82 g/cm3, and an equilibrium temperature of Teq_b=1069+/-16 K. TOI-1685 b is the least dense ultra-short period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting Earth-size planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report a further non-transiting planet candidate in the system, TOI-1685[c], with an orbital period of P_[c]=9.02+0.10-0.12 d.

18 pages, 15 figures

References in corpus (31)

• The Transiting Exoplanet Survey Satellite
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• The K2 Mission: Characterization and Early results
• Bayes in the sky: Bayesian inference and model selection in cosmology
• Gaia Early Data Release 3: The astrometric solution
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Growth Model Interpretation of Planet Size Distribution
• Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators
• Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
• A stellar-mass-dependent drop in planet occurrence rates
• A Study of the Shortest-Period Planets Found With Kepler
• The CARMENES search for exoplanets around M dwarfs: Different roads to radii and masses of the target stars
• Calibrating Gyrochronology using Kepler Asteroseismic targets
• CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS
• CARMENES input catalogue of M dwarfs V. Luminosities, colours, and spectral energy distributions
• Transiting extrasolar planetary candidates in the Galactic bulge
• AMD-stability and the classification of planetary systems
• High-resolution imaging of $Kepler$ planet host candidates. A comprehensive comparison of different techniques
• The CARMENES search for exoplanets around M dwarfs. Activity indicators at visible and near-infrared wavelengths
• The CARMENES search for exoplanets around M dwarfs -- Photospheric parameters of target stars from high-resolution spectroscopy. II. Simultaneous multiwavelength range modeling of activity insensitive lines
• MuSCAT2 multicolour validation of TESS candidates: an ultra-short-period substellar object around an M dwarf
• The CARMENES search for exoplanets around M dwarfs. Three temperate to warm super-Earths
• GJ 1252 b: A 1.2 $R_{\oplus }$ planet transiting an M3-dwarf at 20.4 pc
• Exoplanet Imitators: A test of stellar activity behavior in radial velocity signals
• Exomoons in the habitable zones of M dwarfs
• Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488)
• Can Kozai-Lidov cycles explain Kepler-78b?
• The role of clouds on the depletion of methane and water dominance in the transmission spectra of irradiated exoplanets
• On the Stability of Extrasolar Planetary Systems and other Closely Orbiting Pairs
• Two Bright M Dwarfs Hosting Ultra-Short-Period Super-Earths with Earth-like Compositions

Cited by in corpus (27)

• Density, not radius, separates rocky and water-rich small planets orbiting M dwarf stars
• The CARMENES search for exoplanets around M dwarfs. Guaranteed time observations Data Release 1 (2016-2020)
• TOI-1452 b: SPIRou and TESS reveal a super-Earth in a temperate orbit transiting an M4 dwarf
• A detailed analysis of the Gl 486 planetary system
• Validation of 13 Hot and Potentially Terrestrial TESS Planets
• A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096
• Water absorption in the transmission spectrum of the water-world candidate GJ9827d
• TOI-1468: A system of two transiting planets, a super-Earth and a mini-Neptune, on opposite sides of the radius valley
• TOI-1695 b: A Water World Orbiting an Early M Dwarf in the Planet Radius Valley
• Discovery and mass measurement of the hot, transiting, Earth-sized planet GJ 3929 b
• Gaussian processes for radial velocity modeling Better rotation periods and planetary parameters with the quasi-periodic kernel and constrained priors
• Longitudinally asymmetric stratospheric oscillation on a tidally locked exoplanet
• Precise mass determination for the keystone sub-Neptune planet transiting the mid-type M dwarf G 9-40
• GJ 806 (TOI-4481): A bright nearby multi-planetary system with a transiting hot, low-density super-Earth
• The LHS 1678 System: Two Earth-Sized Transiting Planets and an Astrometric Companion Orbiting an M Dwarf Near the Convective Boundary at 20 pc
• TOI-1075 b: A Dense, Massive, Ultra-Short Period Hot Super-Earth Straddling the Radius Gap
• TOI-1801 b: A temperate mini-Neptune around a young M0.5 dwarf
• A multi-planetary system orbiting the early-M dwarf TOI-1238
• TOI-1442 b and TOI-2445 b: two potentially rocky ultra-short period planets around M dwarfs
• A hot Mars-sized exoplanet transiting an M dwarf
• The CARMENES search for exoplanets around M dwarfs. Revisiting the GJ 581 multi-planetary system with new Doppler measurements from CARMENES, HARPS, and HIRES
• Two sub-Neptunes around the M dwarf TOI-1470
• Searching for Hot Water World Candidates with CHEOPS: Refining the radii and analysing the internal structures and atmospheric lifetimes of TOI-238 b and TOI-1685 b
• The CARMENES search for exoplanets around M dwarfs. A sub-Neptunian mass planet in the habitable zone of HN Lib
• Two Bright M Dwarfs Hosting Ultra-Short-Period Super-Earths with Earth-like Compositions
• TOI-4552 b: A new ultra-short period rocky world revealed by NIRPS and TESS
• TOI-1634 b: an Ultra-Short Period Keystone Planet Sitting Inside the M Dwarf Radius Valley