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Uncorrelated Volatile Behavior during the 2011 Apparition of Comet C/2009 P1 Garradd

Feaga, Lori M. and A'Hearn, Michael F. and Farnham, Tony L. and Bodewits, Dennis and Sunshine, Jessica M. and Gersch, Alan M. and Protopapa, Silvia and Yang, Bin and Drahus, Michal and Schleicher, David G. (2014) Uncorrelated Volatile Behavior during the 2011 Apparition of Comet C/2009 P1 Garradd. Astronomical Journal, 147 (1). Art. No. 24. ISSN 0004-6256.

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The High Resolution Instrument Infrared Spectrometer (HRI-IR) on board the Deep Impact Flyby spacecraft detected H2O, CO2, and CO in the coma of the dynamically young Oort Cloud comet C/2009 P1 (Garradd) post-perihelion at a heliocentric distance of 2 AU. Production rates were derived for the parent volatiles, Q_(H2O) = 4.6 ± 0.8 × 10^(28), Q_(CO2) = 3.9 ± 0.7 × 10^(27), and Q_(CO) = 2.9 ± 0.8 × 10^(28) molecules s^(–1), and are consistent with the trends seen by other observers and within the error bars of measurements acquired during a similar time period. When compiled with other observations of Garradd's dominant volatiles, unexpected behavior was seen in the release of CO. Garradd's H_2O outgassing, increasing and peaking pre-perihelion and then steadily decreasing, is more typical than that of CO, which monotonically increased throughout the entire apparition. Due to the temporal asymmetry in volatile release, Garradd exhibited the highest CO to H_2O abundance ratio ever observed for any comet inside the water snow line at ~60% during the HRI-IR observations. Also, the HRI-IR made the only direct measurement of CO_2, giving a typical cometary abundance ratio of CO_2 to H_2O of 8% but, with only one measurement, no sense of how it varied with orbital position.

Item Type:Article
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URLURL TypeDescription Paper
Farnham, Tony L.0000-0002-4767-9861
Bodewits, Dennis0000-0002-2668-7248
Additional Information:© 2014 American Astronomical Society. Received 2013 June 20; accepted 2013 November 10; published 2013 December 12. This work was funded by NASA, through the Discovery Program, via contract NNM07AA99 C to the University of Maryland and task order NMO711002 to the Jet Propulsion Laboratory. The Jet Propulsion Laboratory is operated by the California Institute of Technology. The authors want to thank all of the Garradd observers with whom we’ve had insightful discussions over the past 2 yr at various conferences and meetings. B. Yang was supported through the NASA Astrobiology Institute under Cooperative Agreement No. NNA08DA77A issued through the Office of Space Science. M. Drahus is a Jansky Fellow of the National Radio Astronomy Observatory, a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. D. Schleicher gratefully acknowledges support by NASA’s Planetary Astronomy Program.
Funding AgencyGrant Number
NASA Discovery ProgramNNM07AA99 C
NASA Discovery ProgramNMO711002
NASA Astrobiology Institute Cooperative AgreementNNA08DA77A
NASA Planetary Astronomy ProgramUNSPECIFIED
Subject Keywords: comets: general; comets: individual (C/2009 P1 Garradd); infrared: planetary systems; techniques: spectroscopic
Issue or Number:1
Record Number:CaltechAUTHORS:20140121-151556636
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Official Citation: Uncorrelated Volatile Behavior during the 2011 Apparition of Comet C/2009 P1 Garradd Lori M. Feaga et al. 2014 The Astronomical Journal 147 24
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43458
Deposited By: Ruth Sustaita
Deposited On:22 Jan 2014 17:37
Last Modified:09 Mar 2020 13:18

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