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.
Comae
Astrophysics - Earth and Planetary Astrophysics
Centaur group
1338
High resolution spectroscopy
271
Radio astronomy
Molecular spectroscopy
215
Comets
1093
Near infrared astronomy
280
2095
2096
Author
Nathan X. Roth
NASA Goddard Space Flight Center
University of Hawaii
Catholic University of America
S.N. Milam
NASA Goddard Space Flight Center
Michael A. DiSanti
NASA Goddard Space Flight Center
Geronimo L. Villanueva
NASA Goddard Space Flight Center
Sara Faggi
American University
NASA Goddard Space Flight Center
B. P. Bonev
American University
Martin A. Cordiner
NASA Goddard Space Flight Center
Catholic University of America
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
NASA Goddard Space Flight Center
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
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
Infrastructure
Onsala Space Observatory
DOI
10.3847/PSJ/ace1e9