papers

Publications (19)

astro-ph.EP2023

A Non-Detection of Iron in the First High-Resolution Emission Study of the Lava Planet 55 Cnc e

Kaitlin C. Rasmussen, Miles H. Currie, Celeste Hagee +17

Close-in lava planets represent an extreme example of terrestrial worlds, but their high temperatures may allow us to probe a diversity of crustal compositions. The brightest and m…

astro-ph.EP2024

TOI-1685 b is a Hot Rocky Super-Earth: Updates to the Stellar and Planet Parameters of a Popular JWST Cycle 2 Target

Jennifer A. Burt, Matthew J. Hooton, Eric E. Mamajek +12

We present an updated characterization of the TOI-1685 planetary system, which consists of a P = 0.69\,day USP super-Earth planet orbiting a nearby ( = 37.6\,pc) M2.5…

astro-ph.EP2022

Unifying High- and Low-resolution Observations to Constrain the Dayside Atmosphere of KELT-20b/MASCARA-2b

David Kasper, Jacob L. Bean, Michael R. Line +10

We present high-resolution dayside thermal emission observations of the exoplanet KELT-20b/MASCARA-2b using the MAROON-X spectrograph. Applying the cross-correlation method with bo…

astro-ph.EP2022

Measuring the Obliquities of the TRAPPIST-1 Planets with MAROON-X

Madison Brady, Jacob Bean, Andreas Seifahrt +6

A star's obliquity with respect to its planetary system can provide us with insight into the system's formation and evolution, as well as hinting at the presence of additional obje…

astro-ph.EP2023

TOI-561 b: A Low Density Ultra-Short Period "Rocky" Planet around a Metal-Poor Star

Casey Brinkman, Lauren M. Weiss, Fei Dai +22

TOI-561 is a galactic thick disk star hosting an ultra-short period (0.45 day orbit) planet with a radius of 1.37 R, making it one of the most metal-poor ([Fe/H] = -0.41…

astro-ph.EP2023

Time-resolved transmission spectroscopy of the ultra-hot Jupiter WASP-189 b

Bibiana Prinoth, H. Jens Hoeijmakers, Stefan Pelletier +14

Ultra-hot Jupiters are tidally locked with their host stars dividing their atmospheres into a hot dayside and a colder nightside. As the planet moves through transit, different reg…

astro-ph.EP2023

Updated Planetary Mass Constraints of the Young V1298 Tau System Using MAROON-X

James Sikora, Jason Rowe, Saugata Barat +14

The early K-type T-Tauri star, V1298 Tau (, ) hosts four transiting planets with radii ranging from . The thre…

astro-ph.EP2025

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…

astro-ph.EP2025

The JWST Rocky Worlds DDT Program reveals GJ 3929b to likely be a bare rock

Qiao Xue, Michael Zhang, Brandon P. Coy +14

We report first results from the JWST Rocky Worlds Director's Discretionary Time program. Two secondary eclipses of the terrestrial exoplanet GJ 3929b were recently observed using…

astro-ph.EP2020

Non-detection of Helium in the Upper Atmospheres of Three Sub-Neptune Exoplanets

David Kasper, Jacob L. Bean, Antonija Oklopčić +5

We present a search for helium in the upper atmospheres of three sub-Neptune size planets to investigate the origins of these ubiquitous objects. The detection of helium for a low…

astro-ph.EP2022

Non-detection of He I in the atmosphere of GJ1214b with Keck/NIRSPEC, at a time of minimal telluric contamination

Jessica J. Spake, Antonija Oklopčić, Lynne. A. Hillenbrand +7

Observations of helium in exoplanet atmospheres may reveal the presence of large gaseous envelopes, and indicate ongoing atmospheric escape. Orell-Miquel et al. (2022) used CARMENE…

astro-ph.EP2019

KELT-23Ab: A Hot Jupiter Transiting a Near-Solar Twin Close to the TESS and JWST Continuous Viewing Zones

Daniel Johns, Phillip Reed, Joseph Rodriguez +55

We announce the discovery of KELT-23Ab, a hot Jupiter transiting the relatively bright () star BD+66 911 (TYC 4187-996-1), and characterize the system using follow-up photo…

astro-ph.EP2025

Calibrating the Instrumental Drift in MAROON-X using an Ensemble Analysis

Ritvik Basant, Tanya Das, Jacob L. Bean +7

MAROON-X is a state-of-the-art extreme precision radial velocity spectrograph deployed on the 8.1-meter Gemini-N telescope on Maunakea, Hawai'i. Using a stabilized Fabry-Pérot eta…

astro-ph.EP2022

A close-in puffy Neptune with hidden friends: The enigma of TOI 620

Michael A. Reefe, Rafael Luque, Eric Gaidos +82

We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA TESS mission. We utilize photometric data from both TESS and…

astro-ph.IM2022

MAROON-X: The first two years of EPRVs from Gemini North

Andreas Seifahrt, Jacob L. Bean, David Kasper +11

MAROON-X is a fiber-fed, optical EPRV spectrograph at the 8-m Gemini North Telescope on Mauna Kea, Hawai'i. MAROON-X was commissioned as a visiting instrument in December 2019 and…

astro-ph.EP2026

Magnetic field strengths of hot giant exoplanets consistent with Solar System values

Julia V. Seidel, Vivien Parmentier, Bibiana Prinoth +29

Magnetic fields are ubiquitous in the universe. They play a key role in shaping the activity of stars, the habitability of rocky planets, and the long-term retention of planetary a…

astro-ph.EP2023

A Wolf 359 in sheep's clothing: Hunting for substellar companions in the fifth-closest system using combined high-contrast imaging and radial velocity analysis

Rachel Bowens-Rubin, Joseph M. Akana Murphy, Philip M. Hinz +16

Wolf 359 (CN Leo, GJ 406, Gaia DR3 3864972938605115520) is a low-mass star in the fifth-closest neighboring system (2.41 pc). Because of its relative youth and proximity, Wolf 359…

astro-ph.EP2023

Vanadium oxide and a sharp onset of cold-trapping on a giant exoplanet

Stefan Pelletier, Björn Benneke, Mohamad Ali-Dib +15

The abundance of refractory elements in giant planets can provide key insights into their formation histories. Due to the Solar System giants' low temperatures, refractory elements…

astro-ph.EP2025

An Aligned Sub-Neptune Revealed with MAROON-X and a Tendency Towards Alignment for Small Planets

Alex S. Polanski, Ian J. M. Crossfield, Andreas Seifahrt +9

We present the Rossiter-McLaughlin measurement of the sub-Neptune TOI-1759A b with MAROON-X. A joint analysis with MuSCAT3 photometry and nine additional TESS transits produces a s…