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A systematic analysis of the mixing ratios with respect to H2O for eight species (CH3OH, HCN, NH3, H2CO, C2H2, C2H6, CH4, and CO) measured with high-resolution infrared spectroscopy in thirty comets between 1997 and 2013 is presented. Some trends are beginning to emerge when mixing ratios in individual comets are compared to average mixing ratios obtained for all species within the population. The...
Carbon dioxide is one of the most abundant ices present in comets and is therefore important for understanding cometary composition and activity. We present analysis of observations of CO2 and [OI] emission in three comets to measure the CO2 abundance and evaluate the possibility of employing observations of [OI] emission in comets as a proxy for CO2. We obtained NIR imaging sensitive to CO2 of comets...
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-m telescope at Apache Point Observatory...
We present analysis of high spectral resolution optical spectra of Comet 103P/Hartley taken during its Fall 2010 apparition. These spectra include transitions belonging to CN, C2, CH, NH2, and OI. We measure production rates and mixing ratios from these spectra. We find evidence for large changes in production rates (factors of a few) over the course of a nucleus rotation, in agreement with other...
We present high-resolution infrared spectroscopic measurements of the ecliptic Comet 2P/Encke, observed on 4–6 November 2003 during its close approach to the Earth, using the Near Infrared Echelle Spectrograph on the Keck II telescope. We present flux-calibrated spectra, production rates, and mixing ratios for H 2 O, CH 3 OH, HCN, H 2 CO, C 2 H 2 , C 2 ...
We obtained high-resolution (λ/Δλ∼28,000) infrared spectra of Comet 103P/Hartley 2 on UT 2010 November 4.6 using the NIRSPEC spectrometer at the W.M. Keck Observatory. Here we present spectra of Hartley 2 between 2.832 and 3.639μm (3531–2748cm −1 ), representing the most complete high-resolution infrared survey of a Jupiter-family comet to date in this wavelength region. We have tabulated...
We present analysis of observations of the forbidden oxygen lines in Comet 103P/Hartley, the target of the Deep Impact Extended Investigation (DIXI), during its Fall 2010 apparition. We obtained the observations using the ARCES echelle spectrometer mounted on the Astrophysical Research Consortium (ARC) 3.5-m telescope at Apache Point Observatory. We detected the 5577, 6300, and 6364Å lines on all...
We conducted high-dispersion spectroscopic observations of Comet 103P/Hartley 2 in the near-infrared wavelength region using the Keck II telescope with NIRSPEC. We obtained observations on four dates, with the last observations performed during the EPOXI closest approach. For this work we focus on the observations performed on UT 2010 October 17 and 21, while observations carried out on UT 2010 September...
We present observations and analysis of the forbidden oxygen lines in Comets C/2006 W3 (Christensen) and C/2007 Q3 (Siding Spring) at heliocentric distances of 3.13 and 2.96AU, respectively. We obtained the observations using the ARCES echelle spectrometer, which is mounted on the Astrophysical Research Consortium 3.5-m telescope at Apache Point Observatory. We detected the 5577, 6300, and 6364Å atomic...
C/2006 P1 McNaught is a dynamically new comet from the Oort cloud that passed very close to the Sun, driving overall volatile production rates up to about 10 31 molecules s −1 . Post-perihelion observations were obtained in a target-of-opportunity campaign using the CSHELL instrument at the NASA Infrared Telescope Facility atop Mauna Kea, Hawaii, on UT 2007 January 27 and 28. Eight...
We used the NIRSPEC instrument on the Keck-2 telescope atop Mauna Kea, HI to observe Comet C/2001 A2 (LINEAR) in a Target of Opportunity campaign on UT 2001 July 9.5, 10.5 August 4.4, 10.5. We measured seven organic parent volatiles (C 2 H 6 , C 2 H 2 , HCN, CH 4 , CO, CH 3 OH, H 2 CO) simultaneously with H 2 O. We obtained absolute production...
The nucleus of Comet C/2001 A2 (LINEAR) split several times during its recent apparition, presenting an unusual opportunity to search for chemical differences in freshly exposed material. We conducted this search using NIRSPEC at the W.M. Keck Observatory on four dates in 2001: 9.5 and 10.5 July and 4.4 and 10.5 August. We detected the R0 and R1 lines of the ν3 vibrational band of CH 4 near...
We obtained high-resolution (λ/Δλ∼25,000) spectra of Comet C/1999 H1 (Lee) on UT 1999 August 19.6 and 21.6 using the cross-dispersed Near InfraRed SPECtrometer (NIRSPEC) at the Keck Observatory atop Mauna Kea, HI. Here we present spectra of Comet Lee between 2.874 and 3.701 μm (3479–2702 cm −1 ) representing the most complete high-resolution infrared survey of a comet to date in this wavelength...
Multiple non-resonance fluorescence lines of water (H 2 O) were detected in Comet 153/P Ikeya–Zhang (2002 C1) between UT 2002 March 21.9 (R h =0.51 AU) and April 13.9 (R h =0.78 AU), using the Cryogenic Echelle Spectrometer (CSHELL) at the NASA Infrared Telescope Facility. Analysis of 2.9-μm water lines enabled accurate determination of rotational temperatures on three dates...
We present absolute abundances and latitudinal variations of ozone and water in the atmosphere of Mars during its late northern spring (L s =67.3 o ) shortly before aphelion. Long-slit maps of the a 1 Δ g state of molecular oxygen (O 2 ) and HDO, an isotopic form of water, were acquired on UT January 21.6 1997 using a high-resolution infrared spectrometer (CSHELL)...
The release of carbon monoxide from Comet C/1995 O1 Hale-Bopp was studied between June 1996 and September 1997 using high resolution infrared spectroscopy near 4.7 μm. The excitation of CO molecules in the coma was assessed through measurement of the rotational temperature on several dates at an angular resolution of ~1 arcsecond. An increase in T rot with distance from the nucleus...
Ethane (C 2 H 6 ) was detected in Comet C/1995 O1 Hale-Bopp on 13 dates between UT 1996 September 20.3 (R h =3.01 AU pre-perihelion) and 1997 September 25.7 (R h =2.83 AU post-perihelion) using high-resolution infrared spectroscopy. Production rates and rotational temperatures were measured, and the derived heliocentric dependence for ethane production was Q=(5.52+/-0...
Water (H 2 O) was detected in Comet C/1995 O1 Hale-Bopp on 10 dates between UT January 21.8 and May 1.2, 1997, using high-resolution infrared spectroscopy. This is the first study of the heliocentric dependence of water released from a comet using direct detection of H 2 O itself. Production rates and rotational temperatures were measured, and the derived heliocentric dependence for...
Hydrogen cyanide (HCN) was detected in Comet Hale-Bopp at infrared wavelengths near 3.0 μm on four dates between Feb 24.0 and May 1.0 1997 using high-resolution spectroscopy. The average rotational temperature retrieved for the (001) vibrational level on UT 1997 April 29.9 was (95+/-6) K near the nucleus, increasing to (122+/-8) K in the intermediate coma (4''-10'' off the nucleus). The HCN production...
Carbonyl sulfide was detected in Comet Hale–Bopp (C/1995 O1) using high dispersion infrared spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. Six lines (P10, P11, P12, P14, P15, and P17) of the ν 3 fundamental band near 4.85 μm were detected on UT April 16.0, April 30.0, and May 1.2, 1997, and two additional lines (P18 and P22) were detected on April 30.0. Water was...
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