activity
20152026
most citedFive Decades of Chromospheric Activity in 59 Sun-like Stars and New Maunder Minimum Candidate HD 166620

54 citations · 368 across the 32 of their papers we have counts for

collaborators

33 papers

astro-ph.EP2026

The NEID Earth Twin Survey. VI. Discovery of a Low-Mass Planet Orbiting HD 126053 and RV Signals Near the Rotation Periods of HD 168009 and HD 10780

Arvind F. Gupta, Sarah E. Logsdon, Jacob K. Luhn +19

Extreme precision radial velocity (EPRV) spectrographs are making strides in extending the limits of radial velocity exoplanet detection. Perhaps the best evidence for this is how…

astro-ph.GA2026

A Galactic-scale extreme-precision radial velocity survey

Sukanya Chakrabarti, Jack Wagner, Robert J. de Rosa +8

We describe the first Galactic-scale extreme-precision radial velocity (EPRV) survey and outline our goals of measuring Galactic accelerations and deriving constraints on the dark…

astro-ph.EP2026

RVTESS I: Modeling Asteroseismic Signals with Simultaneous Photometry and RVs

Jiaxin Tang, Sharon X. Wang, Yaguang Li +22

Detecting small planets via the radial velocity method remains challenged by signals induced by stellar variability, versus the effects of the planet(s). Here, we explore using Gau…

astro-ph.IM2026★ 1 cited

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…

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★ 2 cited

Discovery of a Nearby Habitable Zone Super-Earth Candidate Amenable to Direct Imaging

Corey Beard, Paul Robertson, Jack Lubin +31

We present the discovery of GJ 251 c, a candidate super-Earth orbiting in the Habitable Zone (HZ) of its M dwarf host star. Using high-precision Habitable-zone Planet Finder (HPF)…

astro-ph.EP2025★ 2 cited

An Earth-Sized Planet in a 5.4h Orbit Around a Nearby K dwarf

Kaya Han Taş, Gudmundur Stefansson, Syarief N. M. Fariz +25

We present the discovery and confirmation of the ultra-short period (USP) planet TOI-2431 b orbiting a nearby ( pc) late K star ( = $4109 \pm 28 \, {\rm…

astro-ph.SR2025★ 1 cited

Time-resolved p-mode oscillations for subgiant HD 142091 with NEID at WIYN

Jacob K. Luhn, Paul Robertson, Samuel Halverson +22

Detections of Earth-analog planets in radial velocity observations are limited by stellar astrophysical variability occurring on a variety of timescales. Current state-of-the-art m…

astro-ph.EP2025

The NEID Earth Twin Survey. III. Survey Performance After Three Years on Sky

Arvind F. Gupta, Evan Fitzmaurice, Suvrath Mahadevan +22

The NEID Earth Twin Survey (NETS) has been delivering a rich set of precise radial velocity (RV) measurements for 41 bright, nearby main sequence stars. Here, we describe the statu…

astro-ph.EP2025★ 7 cited

The NEID Earth Twin Survey. II. Dynamical Masses in Seven High-acceleration Star Systems

Mark R. Giovinazzi, Cullen H. Blake, Paul Robertson +26

We present a set of companion dynamical masses and orbital parameters of seven star systems from the NEID Earth Twin Survey with significant absolute astrometric accelerations betw…

astro-ph.EP2025

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…

astro-ph.EP2025★ 2 cited

A Pair of Dynamically Interacting Sub-Neptunes Around TOI-6054

Maxwell A. Kroft, Thomas G. Beatty, Ian J. M. Crossfield +31

We confirm the planetary nature of a pair of transiting sub-Neptune exoplanets orbiting the bright F-type sub-giant star TOI-6054 (, ) as a part of the OrCAS radia…

astro-ph.EP2024

Origins of Super Jupiters: TOI-2145b Has a Moderately Eccentric and Nearly Aligned Orbit

Jiayin Dong, Ashley Chontos, George Zhou +15

Super Jupiters are giant planets with several Jupiter masses. It remains an open question whether these planets originate with such high masses or grow through collisions. Previous…

astro-ph.EP2024

The NEID Earth Twin Survey. I. Confirmation of a 31-day planet orbiting HD 86728

Arvind F. Gupta, Jacob K. Luhn, Jason T. Wright +21

With close to three years of observations in hand, the NEID Earth Twin Survey (NETS) is starting to unearth new astrophysical signals for a curated sample of bright, radial velocit…

astro-ph.EP2024

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…

astro-ph.EP2024★ 1 cited

Data-Driven Modeling of Telluric Features and Stellar Variability with StellarSpectraObservationFitting.jl

Christian Gilbertson, Eric B. Ford, Samuel Halverson +11

A significant barrier to achieving the radial velocity (RV) measurement accuracy and precision required to characterize terrestrial mass exoplanets is the existence of time-variabl…

astro-ph.SR2024

Earths within Reach: Evaluation of Strategies for Mitigating Solar Variability using 3.5 years of NEID Sun-as-a-Star Observations

Eric B. Ford, Chad F. Bender, Cullen H. Blake +15

We present the results of Sun-as-a-star observations by the NEID Solar Telescope at WIYN Observatory, spanning January 1, 2021 through June 30, 2024. We identify 117,060 observatio…

astro-ph.SR2024★ 7 cited

Quiet Please: Detrending Radial Velocity Variations from Stellar Activity with a Physically Motivated Spot Model

Jared C. Siegel, Samuel Halverson, Jacob K. Luhn +15

For solar-type stars, spots and their associated magnetic regions induce radial velocity perturbations through the Doppler rotation signal and the suppression of convective blueshi…

astro-ph.EP2024★ 13 cited

The death of Vulcan: NEID reveals the planet candidate orbiting HD 26965 is stellar activity

Abigail Burrows, Samuel Halverson, Jared C. Siegel +17

We revisit the long-studied radial velocity (RV) target HD26965 using recent observations from the NASA-NSF 'NEID' precision Doppler facility. Leveraging a suite of classical activ…

astro-ph.EP2022★ 15 cited

NEID Reveals that The Young Warm Neptune TOI-2076 b Has a Low Obliquity

Robert C. Frazier, Gudmundur Stefansson, Suvrath Mahadevan +27

TOI-2076 b is a sub-Neptune-sized planet () that transits a young () bright () K-dwarf hosting a system of three transiting…

astro-ph.SR2022★ 11 cited

Detection of p-mode Oscillations in HD 35833 with NEID and TESS

Arvind F. Gupta, Jacob K. Luhn, Jason T. Wright +15

We report the results of observations of p-mode oscillations in the G0 subgiant star HD 35833 in both radial velocities and photometry with NEID and TESS, respectively. We achieve…

astro-ph.EP2022★ 14 cited

GJ 3929: High Precision Photometric and Doppler Characterization of an Exo-Venus and its Hot, Mini-Neptune-mass Companion

Corey Beard, Paul Robertson, Shubham Kanodia +31

We detail the follow up and characterization of a transiting exo-Venus identified by TESS, GJ 3929b, (TOI-2013b) and its non-transiting companion planet, GJ 3929c (TOI-2013c). GJ 3…

astro-ph.SR2022

HD 166620: Portrait of a Star Entering a Grand Magnetic Minimum

Jacob K. Luhn, Jason T. Wright, Gregory W. Henry +2

HD 166620 was recently identified as a Maunder Minimum candidate based on nearly 50 years of Ca II H & K activity data from Mount Wilson and Keck-HIRES (Baum et al. 2022). These da…

astro-ph.EP2022★ 27 cited

Impact of Correlated Noise on the Mass Precision of Earth-analog Planets in Radial Velocity Surveys

Jacob K. Luhn, Eric B. Ford, Zhao Guo +6

Characterizing the masses and orbits of near-Earth-mass planets is crucial for interpreting observations from future direct imaging missions (e.g., HabEx, LUVOIR). Therefore, the E…