TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with the Habitable-Zone Planet Finder

Corey Beard, Paul Robertson, Shubham Kanodia, Jessica Libby-Roberts, Caleb I. Cañas, Arvind F. Gupta, Rae Holcomb, Sinclaire Jones, Henry A. Kobulnicky, Andrea S.J. Lin, Jack Lubin, Marissa Maney, Brock A. Parker, Guðmundur Stefánsson, William D. Cochran, Michael Endl, Leslie Hebb, Suvrath Mahadevan, John Wisniewski, Chad F. BenderScott A. Diddams, Mark Everett, Connor Fredrick, Samuel Halverson, Fred Hearty, Andrew J. Metcalf, Andrew Monson, Joe P. Ninan, Arpita Roy, Maria Schutte, Christian Schwab, Ryan C. Terrien

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


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 (JWST). 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 the Transiting Exoplanet Survey Satellite, the diffuser-assisted Astrophysical Research Consortium (ARC) Telescope Imaging Camera (ARCTIC) imager on the 3.5 m 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 m Hobby-Eberly Telescope, which enabled us to place upper limits on the masses of both transiting planets. TOI-1696b (P = 2.5 days; R p = 3.24 R pdbl; M p < 56.6 M pdbl) falls into a sparsely populated region of parameter space considering its host star's temperature (T eff = 3168 K, M4.5), as planets of its size are quite rare around mid- to late-M dwarfs. On the other hand, TOI-2136b (P = 7.85 days; R p = 2.09 R pdbl; M p < 15.0 M pdbl) is an excellent candidate for atmospheric follow-up with the JWST.

Original languageEnglish (US)
Article number286
JournalAstronomical Journal
Issue number6
StatePublished - Jun 1 2022

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with the Habitable-Zone Planet Finder'. Together they form a unique fingerprint.

Cite this