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Understanding the individual organic components and their distribution in comet 103P/Hartley 2’s innermost coma
Presentation #101.02 in the session Cometary Volatiles.
Published onOct 20, 2022
Understanding the individual organic components and their distribution in comet 103P/Hartley 2’s innermost coma
It has been previously presented that the Deep Impact High Resolution Instrument Infrared spectrometer (DI HRI-IR; 1.05 – 4.83 μm, λ/δλ ~ 250 [1]) detected and mapped the asymmetric spatial distribution of H2O, CO2, a spectral blend of organics (C2H6, CH3OH, CH4, etc.), and water ice in Hartley 2’s innermost coma during its 2010 flyby of the comet [2,3]. Contemporaneous high spectral resolution ground-based data of Hartley 2 [4], as well as data from comet C/1999 H1 (Lee) [5], acquired with the Keck NIRSPEC instrument (λ/δλ ~ 25,000) have been used to test and expand fluorescence models for various volatile organic molecules. These validated and empirically enhanced models are now being convolved to the HRI-IR spectral resolution and applied to the blended organic emission feature between 3 – 4 μm in the DI HRI-IR Hartley 2 spectra to best interpret the data across the full wavelength range of the spectrometer. This presentation connects the spectral content of the organic feature at high (NIRSPEC) and low (HRI-IR) spectral resolution. The systematic approach to fitting the organic blend in specific locations in the coma will be examined with special emphasis on uncertainties due to low λ/δλ. Regions of interest in the coma where the organics are spatially co-located with CO2 gas (small lobe jet), H2O sublimating from the nucleus (waist and sunward activity), and H2O sublimating from water-ice grains (extended anti-sunward water source) are studied individually for their organic composition. These results will aid in our understanding of Hartley 2’s formation, source regions, and processes at work during volatile storage and release.
This research is supported by the NASA DDAP Award 80NSSC18K1041.
[1] Hampton, D.L., et al., 2005, SSR, 117, 43.
[2] A’Hearn, M.F., et al., 2011, Science, 332, 1396.
[3] Feaga, L.F., et al., 2021, BAAS, 53, 208.02.
[4] Dello Russo, N., et al., 2013, Icarus, 222, 707.
[5] Dello Russo, N., et al., 2006, Icarus, 184, 255.
