TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with HPF

Abstract

We present the validation of two planets orbiting M dwarfs, TOI-1696b and TOI-2136b. Both planets are mini-Neptunes orbiting nearby stars, making them promising prospects for atmospheric characterization with the James Webb Space Telescope. We validated the planetary nature of both candidates using high contrast imaging, ground-based photometry, and near-infrared radial velocities. Adaptive Optics images were taken using the ShARCS camera on the 3 m Shane Telescope. Speckle images were taken using the NN-Explore Exoplanet Stellar Speckle Imager on the WIYN 3.5 m telescope. Radii and orbital ephemerides were refined using a combination of TESS, the diffuser-assisted ARC-TIC imager on the 3.5m ARC telescope at Apache Point Observatory, and the 0.6 m telescope at Red Buttes Observatory. We obtained radial velocities using the Habitable-Zone Planet Finder on the 10

Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf

“…During the submission and revision stage of this manuscript, two studies on the TOI-2136 system were announced: Gan et al (2022); Beard et al (2022). Gan et al (2022) used TESS data, ground-based follow-up observations, and the Spirou instrument on the Canada-France-Hawaii Telescope (CFHT) to obtain RV measurements; the study presents a planetary radius of 2.19±0.17 R ⊕ and a mass of 6.4±2.4 M ⊕ for the transiting planet.…”

“…Gan et al (2022) used TESS data, ground-based follow-up observations, and the Spirou instrument on the Canada-France-Hawaii Telescope (CFHT) to obtain RV measurements; the study presents a planetary radius of 2.19±0.17 R ⊕ and a mass of 6.4±2.4 M ⊕ for the transiting planet. Beard et al (2022) used TESS data, ground-based follow-up observations, and the Hobby-Eberly Telescope (HET) instrument Habitable-Zone Planet Finder (HPF) instrument to obtain RV measurements. Beard et al (2022) presents a planetary radius of 2.09 ± 0.08 R ⊕ and a mass upper limit of < 15 M ⊕ , with a median planet mass of 4.64 M ⊕ .…”

“…Beard et al (2022) used TESS data, ground-based follow-up observations, and the Hobby-Eberly Telescope (HET) instrument Habitable-Zone Planet Finder (HPF) instrument to obtain RV measurements. Beard et al (2022) presents a planetary radius of 2.09 ± 0.08 R ⊕ and a mass upper limit of < 15 M ⊕ , with a median planet mass of 4.64 M ⊕ . Our results for the planetary mass and radius of TOI-2136b are consistent with both studies (taking into account the uncertainties).…”