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Record 21 of 1681
MIRO Observation of Comet C/2002 T7 (LINEAR) Water Line Spectrum
External Online Source: hdl:2014/43751
Author and Affiliation:
Lee, Seungwon(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Frerking, Margaret(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Hofstadter, Mark(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Gulkis, Samuel(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
von Allmen, Paul(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Crovisier, Jaques(Observatoire de Paris-Meudon, France)
Biver, Nicholas(Observatoire de Paris-Meudon, France)
Bockelee-Morvan, Dominique(Observatoire de Paris-Meudon, France)
et al.
Abstract: Comet C/2002 T7 (LINEAR) was observed with the Microwave Instrument for Rosetta Orbiter (MIRO) on April 30, 2004, between 5 hr and 16 hr UT. The comet was 0.63AU distance from the Sun and 0.68AU distance from the MIRO telescope at the time of the observations. The water line involving the two lowest rotational levels at 556.936 GHz is observed at 557.070 GHz due to a large Doppler frequency shift. The detected water line spectrum is interpreted using a non local thermal equilibrium (Non-LTE) molecular excitation and radiative transfer model. Several synthetic spectra are calculated with various coma profiles that are plausible for the comet at the time of observations. The coma profile is modeled with three characteristic parameters: outgassing rate, a constant expansion velocity, and a constant gas temperature. The model calculation result shows that for the distant line observation where contributions from a large coma space is averaged, the combination of the outgassing rate and the gas expansion velocity determines the line shape while the gas temperature has a negligible effect. The comparison between the calculated spectra and the MIRO measured spectrum suggests that the outgassing rate of the comet is about 2.0x1029 molecules/second and its gas expansion velocity about 1.2 km/s at the time of the observations.
Publication Date: Oct 02, 2011
Document ID:
20150006615
(Acquired Apr 24, 2015)
Subject Category: ASTRONOMY
Document Type: Conference Paper
Meeting Information: European Planetary Science Congress (EPSC) Joint Meeting ; 2-7 Oct. 2011; Nantes; France
Meeting Sponsor: European Planetary Science Congress; Cascais, Portugal
Financial Sponsor: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA, United States
Description: 3p; In English; Original contains color illustrations
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: COMETS; OUTGASSING; GAS TEMPERATURE; GAS EXPANSION; RADIATIVE TRANSFER; LOCAL THERMODYNAMIC EQUILIBRIUM; MICROWAVE SENSORS; FREQUENCY SHIFT; TELESCOPES; WATER; ROSETTA MISSION
Other Descriptors: COMET; SPECTRAL LINE; ROSETTA; MICROWAVE INSTRUMENT FOR ROSETTA ORBITER (MIRO)
Availability Source: Other Sources
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