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J/ApJ/703/121  Spectroscopy of comet C/2004 Q2 (Machholz)    (Kobayashi+, 2009)

Formation conditions of icy materials in comet C/2004 Q2 (Machholz). I. Mixing ratios of organic volatiles. Kobayashi H., Kawakita H. <Astrophys. J., 703, 121-130 (2009)> =2009ApJ...703..121K
ADC_Keywords: Comets ; Line Profiles ; Spectra, infrared Keywords: comets: general - comets: individual (C/2004 Q2 Machholz) - solar system: formation Abstract: We observed comet C/2004 Q2 (Machholz) with the Keck II telescope in late 2005 January and we obtained the spectra of C/2004 Q2 including many emission lines of volatile species such as H2O, HCN, C2H2, NH3, CH4, C2H6, CH3OH, and H2CO with high-signal-to-noise ratios. Based on our observations, we determined the mixing ratios of the molecules relative to H2O in C/2004 Q2. C/2004 Q2 might be the intermediate type between Oort Cloud and Jupiter Family comets. To investigate the formation conditions of such intermediate type comet, we focused on the (C2H2+C2H6)/H2O ratios and C2H6/(C2H6+C2H2) ratios in comets from the viewpoint of conversion from C2H2 to C2H6 in the precometary ices. We employed the dynamical-evolutional model and the chemical-evolutional model to determine the formation region of C/2004 Q2 more precisely. We found that comet C/2004 Q2 might have formed in relatively inner region of the solar nebula than the typical Oort Cloud comet (but slightly further than 5AU from the proto-Sun). Description: High-resolution spectroscopic observations of comet C/2004 Q2 (Machholz) in near-infrared (the L band) were performed on 2005 January 30, using the Keck II 10m telescope with the NIRSPEC located atop Mauna Kea, Hawaii. In late 2005 January, C/2004 Q2 became as bright as about fourth magnitude in V band and heliocentric distance, geocentric distance, and geocentric velocity were 1.21AU, 0.48AU, and +15.6km/s at the observations, respectively. A photometric standard star (HR937; spectral type is G0V) was observed for flux calibration. The telescope was nodded by 12" along the slit such that the comet remained in the slit for both A and B positions. The observations were acquired in the sequence A-B-B-A. We obtained nine ABBA sequences for the comet and total integration time on the comet was 2160s. The nine ABBA sequences were divided in three sets (1st-3rd seq. for set no.1, 4th-6th seq. for set no.2, and 7th-9th seq. for set no. 3) and these three sets were reduced separately. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 112 109 Line fluxes and g-factors including transmittances
See also: J/ApJS/169/458 : Highly excited H2 in Comets (Liu+, 2007) J/PAZh/30/946 : Unidentified cometary emission lines (Simonia, 2004) J/A+A/393/1053 : 18-cm OH lines in comets (Crovisier+, 2002) J/AJ/112/1197 : Catalog of cometary emission lines (Brown+ 1996) J/A+AS/103/83 : Line identifications in a fireball spectrum (Borovicka 1994) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 A5 --- Mol Molecule name 7- 8 A2 --- f_Line [a-z ] Indicator of blended line (1) 10- 50 A41 --- Line Line assignment (3) 52- 58 F7.2 cm-1 sigma Rest wave number 60- 67 E8.3 W/m2 FSet1 ? Line flux of Set 1 (2) 69- 76 E8.3 W/m2 FSet2 ? Line flux of Set 2 (2) 78- 85 E8.3 W/m2 FSet3 ? Line flux of Set 3 (2) 87- 94 E8.3 W/s gSet1 ? g-factor of Set 1 (emission efficiency) 96-103 E8.3 W/s gSet2 ? g-factor of Set 2 (emission efficiency) 105-112 E8.3 W/s gSet3 ? g-factor of Set 3 (emission efficiency)
Note (1): Blended lines had been removed for C2H2 and NH3. If this flag is active, this line is blended with the previous line (shown just above this line and with the same letter flag). Note (2): Nine ABBA sequences were obtained and were divided in three sets (1st-3rd seq. for set no.1, 4th-6th seq. for set no.2, and 7th-9th seq. for set no. 3) and these three sets were reduced separately. Note (3): Line is written Upper state - Lower state and each state specifies the quantum numbers (v1 v2 v3) J Ka Kc
History: From electronic version of the journal References: Kawakita & Kobayashi. Paper II. 2009ApJ...693..388K
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 12-Oct-2011
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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