76 citations · 434 across the 21 of their papers we have counts for
22 papers
CHIANTE I: Obliquity Measurements of Four High-Priority Ariel Targets in Binaries
Alex S. Polanski, Malena Rice, Catherine A. Clark +10
We present the first results from CHIANTE: a program using the EXtreme PREcision Spectrograph (EXPRES) at the Lowell Discovery Telescope to characterize potential targets of the Ar…
Uncovering Hidden Systematics in Extreme-Precision Radial Velocity Measurements
Lily L. Zhao, Debra A. Fischer, Andrew E. Szymkowiak +2
We identify and correct for small but coherent instrumental drifts in seven years of radial velocity data from the EXtreme PREcision Spectrograph (EXPRES). The systematics are most…
The He I D3 Line as a Proxy for Magnetic Activity using EXPRES Solar Observations
Momo Ellwarth, Joe Llama, Lily L. Zhao +6
Stellar activity remains one of the primary challenges in the detection and characterization of low-mass exoplanets, as it can induce radial velocity (RV) variations that mask or m…
Four sub-Earth planets orbiting Barnard's Star from MAROON-X and ESPRESSO
Ritvik Basant, Rafael Luque, Jacob L. Bean +9
Barnard's Star is an old, single M dwarf star that comprises the second-closest extrasolar system. It has a long history of claimed planet detections from both radial velocities an…
The Lowell Observatory Solar Telescope: A fiber feed into the EXtreme PREcision Spectrometer
Joe Llama, Lily L. Zhao, John M. Brewer +5
The signal induced by a temperate, terrestrial planet orbiting a Sun-like star is an order of magnitude smaller than the host stars' intrinsic variability. Understanding stellar ac…
Planet Hunters TESS V: a planetary system around a binary star, including a mini-Neptune in the habitable zone
Nora L. Eisner, Samuel K. Grunblatt, Oscar Barragán +61
We report on the discovery and validation of a transiting long-period mini-Neptune orbiting a bright (V = 9.0 mag) G dwarf (TOI 4633; R = 1.05 RSun, M = 1.10 MSun). The planet was…
The Extreme Stellar-Signals Project III. Combining Solar Data from HARPS, HARPS-N, EXPRES, and NEID
Lily L. Zhao, Xavier Dumusque, Eric B. Ford +37
We present an analysis of Sun-as-a-star observations from four different high-resolution, stabilized spectrographs -- HARPS, HARPS-N, EXPRES, and NEID. With simultaneous observatio…
Refining the Stellar Parameters of Ceti: a Pole-on Solar Analog
Maria Korolik, Rachael M. Roettenbacher, Debra A. Fischer +16
To accurately characterize the planets a star may be hosting, stellar parameters must first be well-determined. Ceti is a nearby solar analog and often a target for exoplanet s…
EXPRES IV: Two Additional Planets Orbiting Coronae Borealis Reveal Uncommon System Architecture
John M. Brewer, Lily L. Zhao, Debra A. Fischer +7
Thousands of exoplanet detections have been made over the last twenty-five years using Doppler observations, transit photometry, direct imaging, and astrometry. Each of these metho…
Measured Spin-Orbit Alignment of Ultra-Short Period Super-Earth 55 Cancri e
Lily L. Zhao, Vedad Kunovac, John M. Brewer +8
A planet's orbital alignment places important constraints on how a planet formed and consequently evolved. The dominant formation pathway of ultra-short period planets ( day)…
The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
Lily L. Zhao, Debra A. Fischer, Eric B. Ford +40
Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme precisi…
EXPRES. III. Revealing the Stellar Activity Radial Velocity Signature of Eridani with Photometry and Interferometry
Rachael M. Roettenbacher, Samuel H. C. Cabot, Debra A. Fischer +20
The distortions of absorption line profiles caused by photospheric brightness variations on the surfaces of cool, main-sequence stars can mimic or overwhelm radial velocity (RV) sh…
Mapping stellar surfaces III: An Efficient, Scalable, and Open-Source Doppler Imaging Model
Rodrigo Luger, Megan Bedell, Daniel Foreman-Mackey +3
The study of stellar surfaces can reveal information about the chemical composition, interior structure, and magnetic properties of stars. It is also critical to the detection and…
A Stellar Activity F-statistic for Exoplanet Surveys (SAFE)
Parker H. Holzer, Jessi Cisewski-Kehe, Lily Zhao +3
In the search for planets orbiting distant stars the presence of stellar activity in the atmospheres of observed stars can obscure the radial velocity signal used to detect such pl…
EXPRES. II. Searching for Planets Around Active Stars: A Case Study of HD 101501
Samuel H. C. Cabot, Rachael M. Roettenbacher, Gregory W. Henry +7
By controlling instrumental errors to below 10 cm/s, the EXtreme PREcision Spectrograph (EXPRES) allows for a more insightful study of photospheric velocities that can mask weak Ke…
Excalibur: A Non-Parametric, Hierarchical Wavelength-Calibration Method for a Precision Spectrograph
L. L. Zhao, D. W. Hogg, M. Bedell +1
Excalibur is a non-parametric, hierarchical framework for precision wavelength-calibration of spectrographs. It is designed with the needs of extreme-precision radial velocity (EPR…
EXPRES I. HD~3651 an Ideal RV Benchmark
John M. Brewer, Debra A. Fischer, Ryan T. Blackman +10
The next generation of exoplanet-hunting spectrographs should deliver up to an order of magnitude improvement in radial velocity precision over the standard 1 m/s state of the art.…
A Hermite-Gaussian Based Radial Velocity Estimation Method
Parker Holzer, Jessi Cisewski-Kehe, Debra Fischer +1
As the first successful technique used to detect exoplanets orbiting distant stars, the Radial Velocity Method aims to detect a periodic Doppler shift in a star's spectrum. We intr…
High-resolution Transmission Spectroscopy of MASCARA-2 b with EXPRES
H. Jens Hoeijmakers, Samuel H. C. Cabot, Lily Zhao +10
We report detections of atomic species in the atmosphere of MASCARA-2 b, using the first transit observations obtained with the newly commissioned EXPRES spectrograph. EXPRES is a…
Performance Verification of the EXtreme PREcision Spectrograph
Ryan T. Blackman, Debra A. Fischer, Colby A. Jurgenson +25
The EXtreme PREcision Spectrograph (EXPRES) is a new Doppler spectrograph designed to reach a radial velocity measurement precision sufficient to detect Earth-like exoplanets orbit…
An Extreme Precision Radial Velocity Pipeline: First Radial Velocities from EXPRES
Ryan R. Petersburg, J. M. Joel Ong, Lily L. Zhao +13
The EXtreme PREcision Spectrograph (EXPRES) is an environmentally stabilized, fiber-fed, , optical spectrograph. It was recently commissioned at the 4.3-m Lowell Discove…
Planet Detectability in the Alpha Centauri System
Lily L. Zhao, Debra A. Fischer, John M. Brewer +2
We use more than a decade of radial velocity measurements for Cen A, B, and Proxima Centauri from HARPS, CHIRON, and UVES to identify the and orbital periods of plan…