Molecular Outgassing in Centaur 29P/Schwassmann-Wachmann 1 during Its Exceptional 2021 Outburst: Coordinated Multiwavelength Observations Using nFLASH at APEX and iSHELL at the NASA-IRTF
Journal article, 2023
The extraordinary 2021 September-October outburst of Centaur 29P/Schwassmann-Wachmann 1 afforded an opportunity to test the composition of primitive Kuiper disk material at high sensitivity. We conducted nearly simultaneous multiwavelength spectroscopic observations of 29P/Schwassmann-Wachmann 1 using iSHELL at the NASA Infrared Telescope Facility (IRTF) and nFLASH at the Atacama Pathfinder EXperiment (APEX) on 2021 October 6, with follow-up APEX/nFLASH observations on 2021 October 7 and 2022 April 3. This coordinated campaign between near-infrared and radio wavelengths enabled us to sample molecular emission from a wealth of coma molecules and to perform measurements that cannot be accomplished at either wavelength alone. We securely detected CO emission on all dates with both facilities, including velocity-resolved spectra of the CO (J = 2-1) transition with APEX/nFLASH and multiple CO (v = 1-0) rovibrational transitions with IRTF/iSHELL. We report rotational temperatures, coma kinematics, and production rates for CO and stringent (3σ) upper limits on abundance ratios relative to CO for CH4, C2H6, CH3OH, H2CO, CS, and OCS. Our upper limits for CS/CO and OCS/CO represent their first values in the literature for this Centaur. Upper limits for CH4, C2H6, CH3OH, and H2CO are the most stringent reported to date, and are most similar to values found in ultra CO-rich Oort cloud comet C/2016 R2 (PanSTARRS), which may have implications for how ices are preserved in cometary nuclei. We demonstrate the superb synergy of coordinated radio and near-infrared measurements, and advocate for future small-body studies that jointly leverage the capabilities of each wavelength.
2096
Astrophysics - Earth and Planetary Astrophysics
Comae
215
280
Near infrared astronomy
High resolution spectroscopy
Radio astronomy
271
Centaur group
Molecular spectroscopy
1338
2095
Comets
1093
Author
Nathan X. Roth
University of Hawaii
National Aeronautics and Space Administration (NASA)
Catholic University of America
S.N. Milam
National Aeronautics and Space Administration (NASA)
Michael A. DiSanti
National Aeronautics and Space Administration (NASA)
Geronimo L. Villanueva
National Aeronautics and Space Administration (NASA)
Sara Faggi
National Aeronautics and Space Administration (NASA)
American University
B. P. Bonev
American University
Martin A. Cordiner
Catholic University of America
National Aeronautics and Space Administration (NASA)
A. J. Remijan
National Radio Astronomy Observatory
D. Bockelée-Morvan
Paris Descartes University
N. Biver
Paris Descartes University
J. Crovisier
Paris Descartes University
Dariusz C. Lis
California Institute of Technology (Caltech)
Steven B. Charnley
National Aeronautics and Space Administration (NASA)
Emmanuel Jehin
University of Liège
Eva Wirström
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Adam J. McKay
Appalachian State University
Planetary Science Journal
26323338 (eISSN)
Vol. 4 9 172Onsala space observatory infrastructure
Swedish Research Council (VR) (2017-00648), 2018-01-01 -- 2021-12-31.
Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
Infrastructure
Onsala Space Observatory
DOI
10.3847/PSJ/ace1e9