papers

Publications (29)

astro-ph.IM2023

Eureka!: An End-to-End Pipeline for JWST Time-Series Observations

Taylor J. Bell, Eva-Maria Ahrer, Jonathan Brande +12

is a data reduction and analysis pipeline for exoplanet time-series observations, with a particular focus on JWST data. Over the next 1-2 decades, JWST will purs…

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…

astro-ph.EP2025

On Linking Planet Formation Models, Protoplanetary Disk Properties, and Mature Gas Giant Exoplanet Atmospheres

Adina D. Feinstein, Richard A. Booth, Jennifer B. Bergner +34

Measuring a single elemental ratio (e.g., carbon-to-oxygen) provides insufficient information for understanding the formation mechanisms and evolution that affect our observations…

astro-ph.EP2023

Elemental Abundances of the Super-Neptune WASP-107b's Host Star Using High-resolution, Near-infrared Spectroscopy

Neda Hejazi, Ian Crossfield, Thomas Nordlander +8

We present the first elemental abundance measurements of the K dwarf (K7V) exoplanet-host star WASP-107 using high-resolution (R = 45,000), near-infrared (H- and K-band) spectra ta…

astro-ph.EP2022

Identification of carbon dioxide in an exoplanet atmosphere

The JWST Transiting Exoplanet Community Early Release Science Team, Eva-Maria Ahrer, Lili Alderson +129

Carbon dioxide (CO2) is a key chemical species that is found in a wide range of planetary atmospheres. In the context of exoplanets, CO2 is an indicator of the metal enrichment (i.…

astro-ph.EP2022

The TESS Triple-9 Catalog: 999 uniformly vetted candidate exoplanets

Luca Cacciapuoti, Veselin B. Kostov, Marc Kuchner +20

The Transiting Exoplanet Survey Satellite (TESS) has detected thousands of exoplanet candidates since 2018, most of which have yet to be confirmed. A key step in the confirmation p…

astro-ph.EP2024

Clouds and Clarity: Revisiting Atmospheric Feature Trends in Neptune-size Exoplanets

Jonathan Brande, Ian J. M. Crossfield, Laura Kreidberg +12

Over the last decade, precise exoplanet transmission spectroscopy has revealed the atmospheres of dozens of exoplanets, driven largely by observatories like the Hubble Space Telesc…

astro-ph.EP2025

Mapping the SO2 Shoreline in Gas Giant Exoplanets

Ian J. M. Crossfield, Eva-Maria Ahrer, Jonathan Brande +8

JWST has revealed sulfur chemistry in giant exoplanet atmospheres, where molecules such as SO2 trace photochemistry, metallicity, and formation and migration. To ascertain the cond…

astro-ph.EP2019

The L 98-59 System: Three Transiting, Terrestrial-Sized Planets Orbiting a Nearby M-dwarf

Veselin B. Kostov, Joshua E. Schlieder, Thomas Barclay +112

We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-sized planets transiting L 98-59 (TOI-175, TIC 307210830) -- a bright M dwarf at a distanc…

astro-ph.IM2019

Absolute Prioritization of Planetary Protection, Safety, and Avoiding Imperialism in All Future Science Missions: A Policy Perspective

Monica Vidaurri, Alia Wofford, Jonathan Brande +3

The prioritization and improvement of ethics, planetary protection, and safety standards in the astro-sciences is the most critical priority as our scientific and exploratory capab…

astro-ph.EP2026

Glossy Silicate Clouds on the Scorched Dayside of LTT9779b

Suman Saha, James S. Jenkins, Jonathan Brande +10

Discovered deep within the "Neptunian desert", LTT9779b remains the only known ultra-hot Neptune, prompting significant speculation regarding its unique formation and evolutionary…

astro-ph.EP2025

The transmission spectrum of the potentially rocky planet L 98-59 c

Thomas Barclay, Kyle B. Sheppard, Natasha Latouf +32

We present observations of the 1.35+/-0.07 Earth-radius planet L 98-59 c, collected using Wide Field Camera 3 on the Hubble Space Telescope. L 98-59 is a nearby (10.6 pc), bright (…

astro-ph.EP2024

OrCAS: Origins, Compositions, and Atmospheres of Sub-neptunes. I. Survey Definition

Ian J. M. Crossfield, Alex S. Polanski, Paul Robertson +61

Sub-Neptunes - volatile-rich exoplanets smaller than Neptune - are intrinsically the most common type of planet known. However, the formation and nature of these objects, as well a…

astro-ph.EP2023

Water absorption in the transmission spectrum of the water-world candidate GJ9827d

Pierre-Alexis Roy, Björn Benneke, Caroline Piaulet +16

Recent work on the characterization of small exoplanets has allowed us to accumulate growing evidence that the sub-Neptunes with radii greater than often host H…

astro-ph.EP2024

High-resolution Elemental Abundance Measurements of Cool JWST Planet Hosts Using AutoSpecFit: An Application to the Sub-Neptune K2-18b's Host M dwarf

Neda Hejazi, Ian J. M. Crossfield, Diogo Souto +9

We present an in-depth, high-resolution spectroscopic analysis of the M dwarf K2-18 that hosts a sub-Neptune exoplanet in its habitable zone. We show our technique to accurately no…

astro-ph.EP2025

Heat Reveals What Clouds Conceal: Global Carbon & Longitudinally Asymmetric Chemistry on LTT 9779 b

Reza Ashtari, Sean Collins, Jared Splinter +17

LTT-9779 b is an ultra-hot Neptune (Rp ~ 4.7 Re, Mp ~ 29 Me) orbiting its Sun-like host star in just 19 hours, placing it deep within the "hot Neptune desert," where Neptunian plan…

astro-ph.EP2022

GJ 1252b: A Hot Terrestrial Super-Earth With No Atmosphere

Ian J. M. Crossfield, Matej Malik, Michelle L. Hill +16

The increasing numbers of rocky, terrestrial exoplanets known to orbit nearby stars (especially M dwarfs) has drawn increased attention to the possibility of studying these planets…

astro-ph.EP2022

Early Release Science of the Exoplanet WASP-39b with JWST NIRSpec G395H

Lili Alderson, Hannah R. Wakeford, Munazza K. Alam +89

Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems. Access to a…

astro-ph.EP2022

Early Release Science of the exoplanet WASP-39b with JWST NIRCam

Eva-Maria Ahrer, Kevin B. Stevenson, Megan Mansfield +96

Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining the dominant chemical processes at work and, if in eq…

astro-ph.EP2020

The First Habitable Zone Earth-sized Planet from TESS. I: Validation of the TOI-700 System

Emily A. Gilbert, Thomas Barclay, Joshua E. Schlieder +92

We present the discovery and validation of a three-planet system orbiting the nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). TOI-700 lies in the TESS continuous viewing zo…

astro-ph.EP2022

A Mirage or an Oasis? Water Vapor in the Atmosphere of the Warm Neptune TOI-674 b

Jonathan Brande, Ian J. M. Crossfield, Laura Kreidberg +14

We report observations of the recently discovered warm Neptune TOI-674 b (5.25 \rearth{}, 23.6 \mearth{}) with the Hubble Space Telescope's Wide Field Camera 3 instrument. TOI-674…

astro-ph.EP2022

The Exoplanet Modeling and Analysis Center at NASA Goddard

Joe P. Renaud, Eric Lopez, Jonathan Brande +8

The Exoplanet Modeling and Analysis Center (EMAC) at NASA Goddard Space Flight Center is a web-based catalog, repository, and integration platform for modeling and analysis resourc…

astro-ph.EP2025

The SPACE Program. I. The featureless spectrum of HD 86226 c challenges sub-Neptune atmosphere trends

K. Angelique Kahle, Jasmina Blecic, Reza Ashtari +26

Sub-Neptune exoplanets are the most abundant type of planet known today. As they do not have a Solar System counterpart, many open questions exist about their composition and forma…

astro-ph.EP2022

Early Release Science of the exoplanet WASP-39b with JWST NIRISS

Adina D. Feinstein, Michael Radica, Luis Welbanks +86

Transmission spectroscopy provides insight into the atmospheric properties and consequently the formation history, physics, and chemistry of transiting exoplanets. However, obtaini…

astro-ph.EP2022

A transmission spectrum of the sub-Earth planet L98-59~b in 1.1-1.7 m

Mario Damiano, Renyu Hu, Thomas Barclay +20

With the increasing number of planets discovered by TESS, the atmospheric characterization of small exoplanets is accelerating. L98-59 is a M-dwarf hosting a multi-planet system, a…

astro-ph.EP2022

First Detections of Exop(lan)ets: Observations and Follow-Ups of the Floofiest Transits on Zoom

Sabina Sagynbayeva, Briley L. Lewis, Graham M. Doskoch +16

With the proliferation of online Zoom meetings as a means of doing science in the 2020s, astronomers have made new and unexpected Target of Opportunity (ToO) observations. Chief am…

astro-ph.EP2019

The Feasibility of Directly Imaging Nearby Cold Jovian Planets with MIRI/JWST

Jonathan Brande, Thomas Barclay, Joshua E. Schlieder +2

The upcoming launch of the James Webb Space Telescope (JWST) will dramatically increase our understanding of exoplanets, particularly through direct imaging. Microlensing and radia…

astro-ph.EP2024

Sulphur dioxide in the mid-infrared transmission spectrum of WASP-39b

Diana Powell, Adina D. Feinstein, Elspeth K. H. Lee +70

The recent inference of sulphur dioxide (SO) in the atmosphere of the hot (1100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations suggests that phot…

astro-ph.EP2025

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…