Kavli Affiliate: David Charbonneau | Summary:Complex periodic variables (CPVs) are young low-mass stars whose light curves show periodic dips indicative of transiting corotating material. The origin and composition of this material are unclear. Here we present new optical and near-infrared spectroscopy and photometry of four CPVs from Magellan, Keck, Hale, MuSCAT1, MuSCAT2, Tierras, KeplerCam, and […]

Kavli Affiliate: David Charbonneau | Summary:We present the optical design of VIPER: a high-resolution, multimode fiber-fed, narrowband, cross-dispersed, seeing-limited spectrograph based on a Virtually Imaged Phased Array (VIPA), a spectral disperser that provides higher dispersion and a more compact form factor than conventional diffraction gratings. VIPER is specifically designed to probe exoplanet atmospheric escape through […]

Kavli Affiliate: David Charbonneau | Summary:Observations of highly irradiated gas giant exoplanets have shown helium escaping from their atmospheres. There is limited evidence for atmospheres on rocky exoplanets, perhaps because they have already escaped. We report spectroscopic observations of LHS 1140b, a rocky exoplanet that orbits in the habitable zone of a nearby low-mass star. […]

Kavli Affiliate: David Charbonneau | Summary:The Virtually Imaged Phased Array (VIPA) is a spectral disperser that has seen increasing adoption across various applications, including optical telecommunications, high-resolution spectroscopy, and LiDAR. Although VIPAs are typically fed by single-mode optical fiber in these applications, there is growing interest in using a multimode optical fiber feed to enable […]

Kavli Affiliate: David Charbonneau | Summary:We present a uniform spectroscopic characterization of 625 F, G, and K stars hosting 859 confirmed exoplanets using high-resolution archival optical spectra from the Tillinghast Reflector Echelle Spectrograph (TRES). We use the neural network spectral code uberMS, which combines spectra with broadband photometry to estimate precise and accurate stellar parameters. […]

Kavli Affiliate: David Charbonneau | Summary:TOI-4600b and c, originally identified by the Transiting Exoplanet Survey Satellite (TESS) and reported by I. Mireles et al. (2023), are a rare pair of transiting long-period giant planets ($rm P_b=82.7$ days, $rm P_c=482.8$ days) orbiting an early K dwarf. In this work, we refine the orbital parameters of the […]

Kavli Affiliate: David Charbonneau | Summary:We present the results from a five-year campaign to gather multi-epoch, high-resolution spectra of a volume-complete sample of 413 M dwarfs with masses 10-30% that of the Sun that lie within 15 parsecs. We report weighted mean systemic radial velocities (RV) and rotational broadening measurements ($v sin i$) for our […]

Kavli Affiliate: David Charbonneau | Summary:We present an updated characterization of the planetary system orbiting the nearby M2 dwarf GJ 3090 (TOI-177; $d = 22$ pc), based on new high-precision radial velocity (RV) observations from NIRPS and HARPS. With an orbital period of 2.85 d, the transiting sub-Neptune GJ 3090 b has a mass we […]

Kavli Affiliate: David Charbonneau | Summary:We present an updated characterization of the planetary system orbiting the nearby M2 dwarf GJ 3090 (TOI-177; $d = 22$ pc), based on new high-precision radial velocity (RV) observations from NIRPS and HARPS. With an orbital period of 2.85 d, the transiting sub-Neptune GJ 3090 b has a mass we […]

Kavli Affiliate: David Charbonneau | Summary:We report the discovery of TOI-7019b, the first transiting brown dwarf (BD) known to orbit a star that is part of the Milky Way’s ancient thick disk, as defined chemically ([Fe/H] $= -0.79 pm 0.05$ dex, [$α$/Fe] $= +0.26 pm 0.05$ dex, [M/H] $= -0.59 pm 0.06$ dex) and kinematically […]