97 citations · 999 across the 70 of their papers we have counts for
71 papers
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…
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…
The Fe I 4377 Å Line as a Solar Faculae Indicator: Insights from Spectral Ratio Analysis
Katlyn L. Hobbs, Christopher A. Watson, Jean C. Costes +21
Faculae are a dominant source of stellar activity noise in radial velocity measurements, yet their low contrast and broad surface distribution make them difficult to track in disc-…
The KPF-SLOPE Survey - Small, Compact Multi-Planet Systems Appear Spin-Orbit Aligned
Luke B. Handley, Andrew W. Howard, Fei Dai +16
The angle between stellar spin axes and planetary orbits -- stellar obliquity -- probes the dynamics of planetary migration and evolution. The obliquities of giant planets have bee…
Evidence for a Peak at 0.3 in the Eccentricity Distribution of Typical Super-Jovian Exoplanets
Sarah Blunt, Jason Wang, Ruth Murray-Clay +3
In this study, we compute completeness-corrected occurrence rates of giant exoplanets as a function of mass, semimajor axis, and eccentricity, using the approximately uniform Calif…
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…
Scalable Gaussian Processes for Integrated and Overlapping Measurements Via Augmented State Space Models
Ryan A. Rubenzahl, Soichiro Hattori, Simo Särkkä +4
Astronomical measurements are often integrated over finite exposures, which can obscure latent variability on comparable timescales. Correctly accounting for exposure integration w…
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…
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…
A Link Between Rocky Planet Density and Host Star Chemistry
Aida Behmard, Casey L. Brinkman, Soichiro Hattori +2
Planets and their host stars form from the same cloud of gas and dust, so we assume that their chemical compositions are linked. However, a clear correlation between rocky planet i…
TOI-880 is an Aligned, Coplanar, Multi-planet System
Elina Y. Zhang, Huan-Yu Teng, Fei Dai +22
Although many cases of stellar spin-orbit misalignment are known, it is usually unclear whether a single planet's orbit was tilted or if the entire protoplanetary disk was misalign…
A Hot Jupiter with a Retrograde Orbit around a Sun-like Star and a Toy Model of Hot Jupiters in Wide Binary Star Systems
Steven Giacalone, Andrew W. Howard, Ryan A. Rubenzahl +21
We report an observation of a transit of the hot Jupiter (HJ) KELT-23A b with the Keck Planet Finder spectrograph and a measurement of the sky-projected obliquity () of its Sun-…
Stellar Obliquity of the Ultra-Short-Period Planet System HD 93963
Huan-Yu Teng, Fei Dai, Andrew W. Howard +24
We report an observation of the Rossiter-McLaughlin (RM) effect of the transiting planet HD 93963 Ac, a mini-Neptune planet orbiting a G0-type star with an orbital period of $P_{\r…
TOI-6324b: An Earth-Mass Ultra-Short-Period Planet Transiting a Nearby M Dwarf
Rena A. Lee, Fei Dai, Andrew W. Howard +71
We report the confirmation of TOI-6324 b, an Earth-sized (1.059 0.041 R) ultra-short-period (USP) planet orbiting a nearby (20 pc) M dwarf. Using the newly com…
Planet Masses, Radii, and Orbits from NASA's K2 Mission
Andrew W. Howard, Evan Sinukoff, Sarah Blunt +50
We report the masses, sizes, and orbital properties of 86 planets orbiting 55 stars observed by NASA's K2 Mission with follow-up Doppler measurements by the HIRES spectrometer at t…
The TESS-Keck Survey XXIV: Outer Giants may be More Prevalent in the Presence of Inner Small Planets
Judah Van Zandt, Erik A. Petigura, Jack Lubin +38
We present the results of the Distant Giants Survey, a three-year radial velocity (RV) campaign to search for wide-separation giant planets orbiting Sun-like stars known to host an…
An Obliquity Measurement of the Hot Neptune TOI-1694b
Luke B. Handley, Andrew W. Howard, Ryan A. Rubenzahl +9
We present spectral observations of the multiplanet host TOI-1694 during the transit of TOI-1694b, a 26.1 hot Neptune with a 3.77-day orbit. By analyzing radial velociti…
The Compositions of Rocky Planets in Close-in Orbits Tend to be Earth-Like
Casey L. Brinkman, Lauren M. Weiss, Daniel Huber +54
Hundreds of exoplanets between 1-1.8 times the size of the Earth have been discovered on close in orbits. However, these planets show such a diversity in densities that some appear…
The HD 191939 Exoplanet System is Well-Aligned and Flat
Jack Lubin, Erik A. Petigura, Judah Van Zandt +25
We report the sky-projected spin-orbit angle for HD 191939 b, the innermost planet in a 6 planet system, using Keck/KPF to detect the Rossiter-McLaughlin (RM) effect. Planet b…
Asteroseismology of the Nearby K-Dwarf Draconis using the Keck Planet Finder and TESS
Marc Hon, Daniel Huber, Yaguang Li +76
Asteroseismology of dwarf stars cooler than the Sun is very challenging due to the low amplitudes and rapid timescales of oscillations. Here, we present the asteroseismic detection…
The 50-Myr-Old TOI-942c is Likely on an Aligned, Coplanar Orbit and Losing Mass
Huan-Yu Teng, Fei Dai, Andrew W. Howard +4
We report the observation of the transiting planet TOI-942c, a Neptunian planet orbiting a young K-type star approximately 50 Myr years old. Using Keck/HIRES, we observed a partial…
TESS Giants Transiting Giants. VI. Newly Discovered Hot Jupiters Provide Evidence for Efficient Obliquity Damping after the Main Sequence
Nicholas Saunders, Samuel K. Grunblatt, Ashley Chontos +53
The degree of alignment between a star's spin axis and the orbital plane of its planets (the stellar obliquity) is related to interesting and poorly understood processes that occur…
KPF Confirms a Polar Orbit for KELT-18 b
Ryan A. Rubenzahl, Fei Dai, Samuel Halverson +24
We present the first spectroscopic transit results from the newly commissioned Keck Planet Finder on the Keck-I telescope at W. M. Keck Observatory. We observed a transit of KELT-1…
Obliquity Constraints for the Extremely Eccentric Sub-Saturn Kepler-1656 b
Ryan A. Rubenzahl, Andrew W. Howard, Samuel Halverson +25
The orbits of close-in exoplanets provide clues to their formation and evolutionary history. Many close-in exoplanets likely formed far out in their protoplanetary disks and migrat…