Skip to main content
SearchLoginLogin or Signup

NIR Spectral Observations of 29P/Schwassmann-Wachmann 1 with JWST NIRSpec: Constraints on Water, Organics, and Ice Absorption Features

Presentation #400.04 in the session Comets: Coma (Oral Presentation)

Published onOct 23, 2023
NIR Spectral Observations of 29P/Schwassmann-Wachmann 1 with JWST NIRSpec: Constraints on Water, Organics, and Ice Absorption Features

Centaur 29P/Schwassmann-Wachmann 1 (SW1) is a continuously active object with a nearly circular orbit just beyond Jupiter. It undergoes quasi-periodic outbursts whose mechanisms are poorly understood. Hypervolatile species (e.g., CO, CO2) have been considered possible drivers of these outbursts since water sublimation is inefficient at its heliocentric distance, but crystallization of amorphous water ice is another possibility. While CO gas detections are fairly routine for SW1, only a few other molecules such as H2O and HCN have been detected in SW1 (Bockelee-Morvan et al. 2022). More detailed observations are needed to understand this enigmatic object. SW1 was observed using JWST NIRSpec on UT February 20, 2023 as part of GO Program 2416 (PI McKay), one day before an observed optical outburst. The spectra were obtained in PRISM IFU mode, with a wavelength coverage of 0.59 to 5.29µm, covering the fundamental bands of H2O, CO2, and CO, their isotopologues, CO+, as well as ice absorption features from these species. We detected both CO and CO2 in SW1, providing the first detection of CO2 in SW1. Analysis of these species will be presented in a separate presentation by Faggi et al. This presentation will focus on emission from water and organics, and absorption from water ice. We do not detect water emission, unlike previous studies with much larger fields of view (Ootsubo et al. 2012, Bockelee-Morvan et al. 2022), suggesting an icy grain source is responsible for water production in the coma of SW1, as shown by Bockelee-Morvan et al. 2022. An emission feature at 3.4 µm is detected, likely due to a mix of organic species such as C2H6, CH4, and CH3OH. We will also present analysis of the strong 3-µm absorption feature and other candidate ice absorptions in the spectrum. This work was supported by the Space Telescope Science Institute and the NASA-ISFM/FLaRe program.

Comments
0
comment
No comments here