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TOI-2015 is a known exoplanetary system around an M4 dwarf star, consisting of a transiting sub-Neptune planet in a 3.35-day orbital period, TOI-2015 b, accompanied by a non-transiting companion, TOI-2015 c. High-precision radial-velocity measurements were taken with the MAROON-X spectrograph, and high-precision photometric data were collected, primarily using the SPECULOOS, MUSCAT, TRAPPIST and LCOGT networks. We collected 63 transit light curves and 49 different transit epochs for TOI-2015 b. We recharacterized the target star by combining optical spectra obtained by the MAROON-X, Shane/KAST and IRTF/SpeX spectrographs, Bayesian model averaging (BMA) and spectral energy distribution (SED) analysis. The TOI-2015 host star is aK= 10.3 mag M4-type dwarf with a subsolar metallicity of [Fe/H] = −0.31 ± 0.16, and an effective temperature ofT_eff≈ 3200 K. Our photodynamical analysis of the system strongly favors the 5:3 mean-motion resonance and in this scenario the planet b (TOI-2015 b) has an orbital period ofP_b= 3.34 days, a mass ofM_p= 9.02_-0.36^+0.32M_⊕, and a radius ofR_p= 3.309_-0.011^+0.013R_⊕, resulting in a density ofρ_p= 0.25 ± 0.01ρ_⊕= 1.40 ± 0.06 g cm⁻³; this is indicative of a Neptune-like composition. Its transits exhibit large (> 1 hr) timing variations characteristic of an outer perturber in the system. We performed a global analysis of the high-resolution radial-velocity measurements, the photometric data, and the TTVs, and inferred that TOI-2015 hosts a second planet, TOI-2015 c, in a non-transiting configuration. Our analysis places it near a 5:3 resonance with an orbital period ofP_c= 5.583 days and a mass ofM_p= 8.91_-0.40^+0.38M_⊕. The dynamical configuration of TOI-2015 b and TOI-2015 c can be used to constrain the system’s planetary formation and migration history. Based on the mass-radius composition models, TOI-2015 b is a water-rich or rocky planet with a hydrogen-helium envelope. Moreover, TOI-2015 b has a high transmission-spectroscopic metric (TSM=149), making it a favorable target for future transmission spectroscopic observations with theJWSTto constrain the atmospheric composition of the planet. Such observations would also help to break the degeneracies in theoretical models of the planet’s interior structure. 

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 ( P b = 1.88 d), has a planetary mass of M b = 3.21 ± 0.24 M ⊕ and a radius of R b = 1.280 −0.039 +0.038 R ⊕ , resulting in a density of ρ b = 8.39 −0.92 +1.05 g cm −3 , which is consistent with a mostly rocky composition. For the outer planet, TOI-1468 c ( P c = 15.53 d), we derive a mass of M c = 6.64 −0.68 +0.67 M ⊕ ,aradius of R c = 2.06 ± 0.04 R ⊕ , and a bulk density of ρ c = 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. 

We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, m b = 30.8 ± 1.5 M ⊕ , R b = 4.7 ± 0.3 R ⊕ ) located in the “hot Neptune desert”. Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer , and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TÜBİTAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP 714-47 b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP 714-47 is a slowly rotating early M dwarf ( T eff = 3950 ± 51 K) with a mass of 0.59 ± 0.02 M ⊙ and a radius of 0.58 ± 0.02 R ⊙ . From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33 d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained.