activity
20232026
collaborators

10 papers

astro-ph.SR2026

Predicting Macroturbulence in F/G/K Dwarfs to 100 m/s Precision

Jack Lubin, Erik Petigura, Kento Masuda +6

We leverage the high resolution and spectral stability of the Keck Planet Finder (KPF) spectrograph to investigate macroturbulence broadening via the stellar cross-correlation func…

astro-ph.EP2026

POSEIDON III: The Aligned Orbit of the Hot Neptune Around the Hot Star WASP-195

Juan I. Espinoza-Retamal, Joshua N. Winn, Rafael Brahm +33

Stellar obliquities provide important clues as to the formation and migration histories of planetary systems, but measurements remain scarce for Neptune-mass planets, especially th…

astro-ph.EP2026

Spin-Orbit Alignment of Two Neptune-size Planets Younger than 500 Myr: TOI-560 b and TOI-5082 b

Elina Y. Zhang, Fei Dai, Andrew W. Howard +25

Stellar obliquity measurements provide a direct probe of planetary system dynamics, but remain sparse for Neptune-size planets, particularly at young ages. We present Rossiter-McLa…

astro-ph.EP2026

TOI-4495: A Pair of Aligned, Near-Resonant Sub-Neptunes that Likely Experienced Overstable Migration

Mu-Tian Wang, Fei Dai, Hui-Gen Liu +24

We report the discovery of a sub-Neptune and a Neptune-like planet (, ) orbiting the F-type star TOI-449…

astro-ph.IM2026

Exposure-averaged Gaussian Processes for Combining Overlapping Datasets

Jacob K. Luhn, Ryan A. Rubenzahl, Samuel Halverson +1

Physically motivated Gaussian process (GP) kernels for stellar variability, like the commonly used damped, driven simple harmonic oscillators that model stellar granulation and p-m…

astro-ph.EP2025

Precise Radial Velocities

Jennifer A. Burt, Xavier Dumusque, Samuel Halverson

Precise measurements of a star's radial velocity (RV) made using extremely stable, high resolution, optical or near infrared spectrographs can be used to determine the masses and o…

astro-ph.EP2025

The KPF SURFS-UP Survey I: Transmission Spectroscopy of WASP-76 b

Aaron Householder, Fei Dai, Aurora Kesseli +25

We introduce the KPF SURFS-UP (Spectroscopy of the Upper-atmospheres and ReFractory Species in Ultra-hot Planets) Survey, a high-resolution survey to investigate the atmospheric co…

astro-ph.EP2025

An Hα Transit of HD 189733b to Assess Stellar Activity Across the Transit Chord Close to JWST Observations

Kingsley E. Ehrich, Jason A. Dittmann, Samuel P. Halverson +1

Transmission spectroscopy allows us to detect molecules in planetary atmospheres, but is subject to contamination from inhomogeneities on the stellar surface. Quantifying the exten…

astro-ph.IM2023

Calibration Unit Design for High-Resolution Infrared Spectrograph for Exoplanet Characterization (HISPEC)

Ben Sappey, Quinn Konopacky, Nemanja Jovanovic +13

The latest generation of high-resolution spectrograph instruments on 10m-class telescopes continue to pursue challenging science cases. Consequently, ever more precise calibration…

astro-ph.IM2023

Staring at the Sun with the Keck Planet Finder: An Autonomous Solar Calibrator for High Signal-to-Noise Sun-as-a-Star Spectra

Ryan A. Rubenzahl, Samuel Halverson, Josh Walawender +11

Extreme precision radial velocity (EPRV) measurements contend with internal noise (instrumental systematics) and external noise (intrinsic stellar variability) on the road to 10 cm…