100 citations · 143 across the 24 of their papers we have counts for
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A JWST Study of Stardust. II. Polycyclic Aromatic Hydrocarbons in Comet 81P/Wild 2 and Implications for Primitive Solar System Carbon
Nathan X. Roth, Stefanie N. Milam, Diane H. Wooden +11
We report observations of comet 81P/Wild 2, target of the Stardust sample return mission, on UT 2023 March 20 and 24 at a heliocentric distance () of 1.85 au using the NIRSpec…
Tails and Trails: Comets and NEOs Survive Co-addition in Rubin Early Data Preview 2
Colin Orion Chandler, Joseph Murtagh, Ian Chow +11
We identify effectively single-visit imaging hidden within the deep co-added images of the NSF-DOE Vera C. Rubin Observatory Early Data Preview 2 (EDP2). These shallow regions cont…
JWST Reveals Refractory-Rich Water Ice in Interstellar Comet 3I/ATLAS: Evidence for a Continuum of Grain Properties across Protoplanetary Disks
Silvia Protopapa, Michael S. P. Kelley, Martin A. Cordiner +12
We present JWST/NIRSpec PRISM observations of the interstellar comet 3I/ATLAS obtained on 2025 August 6 (Epoch 1), 2025 December 22 (Epoch 2), and 2026 April 1 (Epoch 3), spanning…
The Highly Unusual Behavior and Chemical Composition of Interstellar Comet 2I/Borisov
Allison N. Bair, David G. Schleicher, Theodore Kareta +2
We report on imaging, spectroscopy, and narrowband photometry of interstellar comet 2I/Borisov obtained at Lowell Observatory from 2019 September 13 to December 16. We measured che…
JWST Spatial-Spectral Mapping of Green Comet C/2022 E3 (ZTF)
Stefanie N. Milam, Nathan X. Roth, Geronimo L. Villanueva +9
We report a survey of molecular emission from cometary volatiles using the James Webb Space Telescope (JWST) toward Oort cloud comet C/2022 E3 (ZTF) carried out on UT 2023 February…
A JWST Study of Stardust. I. Infrared Spectroscopy of Comet 81P/Wild 2 and Overall Composition
Nathan X. Roth, Stefanie N. Milam, Diane H. Wooden +11
We report observations of comet 81P/Wild 2, target of the Stardust sample return mission, on UT 2023 March 20 and 24 at a heliocentric distance () of 1.85 au using the NIRSpec…
Multi-year Ground-Based Survey Photometry of Active Comet 103P/Hartley 2 and Centaur (2060) Chiron: A Tale of Two Comets in the Pre-LSST Era
Joseph Murtagh, Megan E. Schwamb, Michael S. P. Kelley +22
Comets and Centaurs trace the evolution of trans-Neptunian objects (TNOs) into the inner solar system. Their activity reflects the interplay between volatile sublimation, dust dyna…
A Look at Eight Outbursts of Comet 7P/Pons-Winnecke
Ky Huynh, Michael S. P. Kelley, Jessica M. Sunshine +6
Cometary outbursts may be used as a means to infer the physical processes occurring on cometary nuclei. To that end, we studied eight outbursts of comet 7P/Pons-Winnecke identified…
Characterization of the Volatile Properties of 133P/Elst-Pizarro and Other Main-Belt Comets with JWST and Ground-Based Observations
Henry H. Hsieh, John W. Noonan, Michael S. P. Kelley +10
We report results from an analysis of the volatile composition and evolution of main-belt comet (MBC) 133P/Elst-Pizarro using JWST NIRSpec and NIRCam observations and ground-based…
Emerging Diversity Among the Main-Belt Comets: Insights from JWST and Ground-Based Observations of 457P/Lemmon-PANSTARRS
John W. Noonan, Henry H. Hsieh, Michael S. P. Kelley +10
We present JWST NIRSpec and NIRCam observations of 457P/Lemmon-PANSTARRS, a main-belt comet that displayed activity around its 2020 perihelion and that was observed to regain activ…
Isotopic Evidence for a Cold and Distant Origin of the Interstellar Object 3I/ATLAS
Martin Cordiner, Nathan X. Roth, Marco Micheli +16
Interstellar objects provide the only directly observable samples of icy planetesimals formed around other stars, and can therefore provide insight into the diversity of physical a…
Time-Domain Photometry and Activity Evolution of Interstellar Comet 3I/ATLAS with BHTOM
A. Fraser Gillan, Łukasz Wyrzykowski, Przemysław J. Mikołajczyk +69
Time-domain photometric monitoring is essential for characterizing cometary evolution, particularly for rare interstellar objects with limited observing opportunities. We aimed to…
Coma Physics of an Interstellar Object: JWST Spatial-Spectral Mapping of 3I/ATLAS
Nathan X. Roth, Martin A. Cordiner, Stefanie N. Milam +17
We report a survey of molecular emission from cometary volatiles using the James Webb Space Telescope (JWST) toward interstellar object 3I/ATLAS carried out on UT 2025 December 22…
An Enriched Methane D/H Ratio in the Interstellar Object 3I/ATLAS
Nathan X. Roth, Martin Cordiner, Stefanie Milam +15
Interstellar objects are interlopers from other planetary systems, and their volatile compositions provide a glimpse into planet formation around their host star. We present near-i…
Observations of [O I] emission in Comets C/2014 Q2 (Lovejoy) and C/2007 N3 (Lulin): Possible Influence of Solar Activity on Oxygen Line Ratios
Ella J. Mayfield, Adam J. McKay, Michael S. P. Kelley +1
Observing [O I] emission to calculate an "oxygen line ratio" has been proposed as a potential proxy for direct CO measurement in comets. However, the photochemistry governing […
Sequential Fragmentation of C/2025 K1 (ATLAS) After Its Near-Sun Passage
Dennis Bodewits, John W. Noonan, Michael S. P. Kelley +6
Comet C/2025 K1 (ATLAS) reached perihelion at 0.33 au on 2025 October 8. Daily monitoring by the LCO Outbursting Objects Key Project revealed a major activity increase between Nove…
JWST detection of a carbon dioxide dominated gas coma surrounding interstellar object 3I/ATLAS
Martin A. Cordiner, Nathaniel X. Roth, Michael S. P. Kelley +10
3I/ATLAS is the third confirmed interstellar object to visit our Solar System, and only the second to display a clear coma. Infrared spectroscopy with the James Webb Space Telescop…
Optical and Near-Infrared Spectroscopy of the Outbursting Comet 12P/Pons-Brooks
Ruining Zhao, Bin Yang, Michael S. P. Kelley +4
We present optical and near-infrared (NIR) observations of the outbursting, Halley-type comet 12P/Pons-Brooks. Three NIR spectra were obtained during two outbursts in October and N…
A Large Outburst, Coma Asymmetries, and the Color of Comet 243P/NEAT
Michael S. P. Kelley, Silvia Protopapa, Dennis Bodewits +16
Water ice is a fundamental building material of comets and other bodies in the outer solar system. Yet, the properties of cometary water ice are challenging to study, due to its vo…
Sorcha: A Solar System Survey Simulator for the Legacy Survey of Space and Time
Stephanie R. Merritt, Grigori Fedorets, Megan E. Schwamb +20
The upcoming Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory is expected to revolutionize solar system astronomy. Unprecedented in scale, this ten-year wide…
First Detection of Molecular Activity in the Largest Known Oort Cloud Comet: ALMA Imaging of C/2014 UN271 (Bernardinelli-Bernstein) at 16.6 au from the Sun
Nathan X. Roth, Stefanie N. Milam, Martin A. Cordiner +12
We report observations of comet C/2014 UN271 (Bernardinelli-Bernstein) carried out on UT 2024 March 8 and 17 at a heliocentric distance () of 16.6 au using the Atac…
A JWST Study of the Remarkable Oort Cloud Comet C/2017 K2 (PanSTARRS)
Charles E. Woodward, Dominique Bockelee-Morvan, David E. Harker +4
Comets, during their journeys into the inner solar system, deliver volatile gases, organics, and particulates into their comae that provide crucial information for assessing the ph…
First JWST spectrum of distant activity in Long Period Comet C/2024 E1 (Wierzchos)
Colin Snodgrass, Carrie E. Holt, Michael S. P. Kelley +10
We observed the new Long Period Comet C/2024 E1 (Wierzchos), inbound at 7 au from the Sun, using the NIRSpec integral field unit on JWST. The spectrum shows absorption features due…
The Volatile Composition and Activity Evolution of Main-Belt Comet 358P/PANSTARRS
Henry H. Hsieh, John W. Noonan, Michael S. P. Kelley +17
We report the detection of water vapor associated with main-belt comet 358P/PANSTARRS on UT 2024 January 8-9 using the NIRSPEC instrument aboard JWST. We derive a water production…