Evolution of H${}_2$O, CO, and CO${}_2$ Production in Comet C/2009 P1 Garradd During the 2011-2012 Apparition

Abstract

We present analysis of high spectral resolution NIR spectra of CO and H${}_2$O in comet C/2009 P1 (Garradd) taken during its 2011-2012 apparition with the CSHELL instrument on NASA's Infrared Telescope Facility (IRTF). We also present analysis of observations of atomic oxygen in comet Garradd obtained with the ARCES echelle spectrometer mounted on the ARC 3.5-meter telescope at Apache Point Observatory and the Tull Coude spectrograph on the Harlan J. Smith 2.7-meter telescope at McDonald Observatory. The observations of atomic oxygen serve as a proxy for H${}_2$O and CO${}_2$. We confirm the high CO abundance in comet Garradd and the asymmetry in the CO/H${}_2$O ratio with respect to perihelion reported by previous studies. From the oxygen observations, we infer that the CO${}_2$/H${}_2$O ratio decreased as the comet moved towards the Sun, which is expected based on current sublimation models. We also infer that the CO${}_2$/H${}_2$O ratio was higher pre-perihelion than post-perihelion. We observe evidence for the icy grain source of H${}_2$O reported by several studies pre-perihelion, and argue that this source is significantly less abundant post-perihelion. Since H${}_2$O, CO${}_2$, and CO are the primary ices in comets, they drive the activity. We use our measurements of these important volatiles in an attempt to explain the evolution of Garradd's activity over the apparition.

35 pages, 10 figures, 9 tables, accepted for publication in Icarus

References in corpus (5)

• The Evolving Activity of the Dynamically Young Comet C/2009 P1 (Garradd)
• Coupled Chemistry-Emission Model for Atomic Oxygen Green and Red-doublet Emissions in Comet C/1996 B2 Hyakutake
• Ground-based Optical and SPITZER Infrared Imaging Observations of Comet 21P/Giacobini-Zinner
• Atomic Oxygen in the Comae of Comets
• Photochemistry of atomic oxygen green and red-doublet emissions in comets at larger heliocentric distances

Cited by in corpus (10)

• CO in distantly active comets
• Evolution of CO${}_2$, CH${}_4$, and OCS abundances relative to H${}_2$O in the coma of comet 67P around perihelion from Rosetta/VIRTIS-H observations
• Detection of a Water Tracer in Interstellar Comet 2I/Borisov
• High resolution optical spectroscopy of the ${\mathrm{N}}_2$-rich comet C/2016 R2 (PanSTARRS)
• The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission
• Polarimetry, photometry, and spectroscopy of comet C/2009 P1(Garradd)
• Observational Constraints on Water Sublimation from 24 Themis and 1 Ceres
• The pre-perihelion activity of dynamically new comet C/2013 A1 (Siding Spring) and its close encounter with Mars
• High-resolution optical spectroscopic observations of comet 21P/Giacobini-Zinner in Its 2018 apparition
• Carbon dioxide clathrate hydrate formation at low temperature. Diffusion-limited kinetics growth as monitored by FTIR