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This discusses an educational strategy designed to create a means for students to connect skills introduced in a course sequence during their second professional year with an evaluative Doctor of Pharmacy project conducted later in the curriculum. (Author)

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2006.11.009 Byline: Erika L. Gibb (a), Michael A. DiSanti (b), Karen Magee-Sauer (c), Neil Dello Russo (d), Boncho P. Bonev (e)(f), Michael J. Mumma (f) Keywords: Comets; composition; Infrared observations; Spectroscopy Abstract: 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 [nu].sub.3 vibrational band of CH.sub.4 near 3.3 [mu]m on all dates. The R2 line was detected on 4.4 and 10.5 August. When we compare production rates of CH.sub.4 to H.sub.2O, we find evidence of a significant enhancement in August relative to that found in July. H.sub.2CO was securely detected via its [nu].sub.1 and [nu].sub.5 bands on 9.5 July. On 10.5 July, H.sub.2CO emission was much weaker, and its mixing ratio had dropped by a factor of about four. The mixing ratios for other detected volatile species did not change significantly over the course of the observations. We discuss the implications of this evidence for chemical heterogeneity in the nucleus of Comet C/2001 A2. Author Affiliation: (a) Department of Physics & Astronomy, University of Missouri-St. Louis, St. Louis, MO 63121, USA (b) Planetary Systems Laboratory, Solar System Exploration Division, NASA Goddard Space Flight Center, Code 693, Greenbelt, MD 20771, USA (c) Department of Chemistry and Physics, Rowan University, Glassboro, NJ 08028-1701, USA (d) Space Department, Planetary Exploration Group, Applied Physics Laboratory/Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD 20723-6099, USA (e) Department of Physics, The Catholic University of America, Washington, DC 20064, USA (f) Solar System Exploration Division, NASA Goddard Space Flight Center, Code 690, Greenbelt, MD 20771, USA Article History: Received 17 January 2006; Revised 27 September 2006

Byline: Michael A. DiSanti (a), Geronimo L. Villanueva (a), Boncho P. Bonev (a)(b), Karen Magee-Sauer (c), James E. Lyke (d), Michael J. Mumma (e) Keywords: Comets; Spectroscopy; Infrared observations Abstract: The Deep Impact encounter with the Jupiter family Comet 9P/Tempel 1 on UT 2005 July 4 was observed at high spectral resolving power (I'/[delta]I'[approximately equal to]25,000) using the cross-dispersed near-infrared echelle spectrometer (NIRSPEC) at Keck-2. We report the temporal evolution of parent volatiles and dust (simultaneously measured) resulting from the event. Column abundances are presented for H.sub.2O and C.sub.2H.sub.6 beginning 30 min prior to impact (T-30) and ending 50 min following impact (T+50), and for H.sub.2O and HCN from T+50 until T+96, in time steps of approximately 6 min post-impact. The ejecta composition was revealed by an abrupt increase in H.sub.2O and C.sub.2H.sub.6 near T+25. This showed C.sub.2H.sub.6/H.sub.2O to be higher than its pre-impact value by a factor 2.4[+ or -]0.5, while HCN/H.sub.2O was unchanged within the uncertainty of the measurements. The mixing ratios for C.sub.2H.sub.6 and HCN in the ejecta agree with those found in the majority of Oort cloud comets, perhaps indicating a common region of formation. The expanding dust plume was tracked by continuum measurements, both through the 3.5-[mu]m spectral continuum and through 2-[mu]m images acquired with the SCAM slit-viewing camera, and each showed a monotonic increase in continuum intensity following impact. A Monte Carlo model that included dust opacity was applied to the dust coma, and its parameters were constrained by observations; the simulated continuum intensities reproduced both spectral and SCAM data. The relatively sudden appearance of the volatile ejecta signature is attributed to heating of icy grains (perhaps to a threshold temperature) that are decreasingly shadowed by intervening (sunward) dust particles in an optically thick ejecta plume, perhaps coupled with an accelerated decrease in dust optical depth near T+25. Author Affiliation: (a) Solar System Exploration Division, NASA Goddard Space Flight Center, Code 693, Greenbelt, MD 20771, USA (b) Department of Physics, The Catholic University of America, Washington, DC 20064, USA (c) Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028-1701, USA (d) W.M. Keck Observatory, 65-1120 Mamalahoa Hwy, Kamuela, HI 96743, USA (e) Solar System Exploration Division, NASA Goddard Space Flight Center, Code 690, Greenbelt, MD 20771, USA Article History: Received 8 May 2006; Revised 13 September 2006

We obtained high-resolution ([lambda]/[DELTA][lambda] ~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 [micro]m (3479-2702 [cm.sup.-1]) representing the most complete high-resolution infrared survey of a comet to date in this wavelength region. Using published line lists and laboratory spectra we have identified 444 of the 545 distinct emission features present in these spectra. We have tabulated the rest frequencies, assignments, relative intensities, and signal-to-noise ratios of all detected emissions. In addition to gaining insights into the chemistry of Comet Lee, this survey provides a valuable tool for planning future high-resolution infrared observations of comets and other astronomical targets, and for retrospective comparison to existing high-resolution infrared datasets. Keywords: Comets; Infrared; Observations; Spectroscopy

Multiple non-resonance fluorescence lines of water ([H.sub.2]O) were detected in Comet 153/P Ikeya-Zhang (2002 C1) between UT 2002 March 21.9 ([R.sub.h] = 0.51 AU) and April 13.9 ([R.sub.h] = 0.78 AU), using the Cryogenic Echelle Spectrometer (CSHELL) at the NASA Infrared Telescope Facility. Analysis of 2.9-[micro]m water lines enabled accurate determination of rotational temperatures on three dates. The derived [H.sub.2]O rotational temperatures were [138.sup.+6.sub.-5], [141.sup.+10.sub.-9], and 94 [+ or -] 3 K on UT 2002 March 22.0, March 23.0, and April 13.8, respectively. Water production rates were retrieved from spectral lines measured in nineteen separate grating settings over seven observing periods. The derived heliocentric dependence of the water production rate was Q = (9.2 [+ or -] 1.1) x [10.sup.28][[R.sup.(-3.21[+ or -]0.26).sub.h] molecules [s.sup.-1]. The spatial distribution of [H.sub.2]O in the coma was consistent with its release directly from the nucleus (as a native source) on all dates. Keywords: Comets Ikeya-Zhang; Infrared Spectroscopy: Water

We present absolute abundances and latitudinal variations of ozone and water in the atmosphere of Mars during its late northern spring ([L.sub.s] = 67.3[degrees]) shortly before aphelion. Long-slit maps of the [a.sup.1][[DELTA].sub.g] state of molecular oxygen ([O.sub.2]) and HDO, an isotopic form of water, were acquired on UT January 21.6 1997 using a high-resolution infrared spectrometer (CSHELL) at the NASA Infrared Telescope Facility. [O.sub.2]([a.sup.1][[DELTA].sub.g]) is produced by ozone photolysis, and the ensuing dayglow emission at 1.27 [micro]m is used as a tracer for ozone. Retrieved vertical column densities for ozone above ~20 km ranged between 1.5 and 2.8 [micro]m-atm at mid-to low latitudes (30[degrees]S-60[degrees]N) and decreased outside that region. A significant decrease in ozone density is seen near 30[degrees]N (close to the subsolar latitude of 23.5[degrees]N). The rotational temperatures retrieved from [O.sub.2](a-X) emissions show a mean of 172 [+ or -] 2.5 K, confirming that the sensed ozone lies in the middle atmosphere (~24 km). The [v.sub.1] fundamental band of HDO near 3.67 [micro]m was used as a proxy for [H.sub.2]O. The retrieved vertical column abundance of water varies from 3 precipitable microns (pr-[micro]m) at ~30[degrees]S to 24 pr-[micro]m at ~60[degrees]N. We compare these results with current photochemical models and with measurements obtained by other methods. Key Words: Mars atmosphere; composition; infrared observations; spectroscopy; photochemistry.

The release of carbon monoxide from Comet C/1995 O1 HaleBopp was studied between June 1996 and September 1997 using high resolution infrared spectroscopy near 4.7 [micro]m. 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 Trot with distance from the nucleus was revealed, most likely because of photolytic heating by fast H-atoms. Observed temperature profiles varied from date to date, but overall the degree of heating was most pronounced near perihelion. The similar rotational temperatures observed for CO and HCN may indicate control of rotational populations by collisions with electrons. The spatial distribution of CO molecules in the coma revealed two distinct sources for CO, one being CO ice native to the nucleus, and another being CO released from a progenitor distributed in the coma. Only the native source was seen when the comet was beyond 2 AU from the Sun. Based on pre- and post-perihelion observations on five dates with heliocentric distance [R.sub.h] between 4.10 and 2.02 AU, a heliocentric dependence [Q.sub.CO,native] = (1.06 [+ or -] 0.44) x [10.sup.30] [R.sup.-1.76 [+ or -] 0.26.sub.h] molecules [s.sup.-1] was obtained. Within [R.sub.h] ~ 1.5 AU, however, both native and distributed sources were consistently present on all dates of observation. The total CO produced was the sum of the two sources and, based on seven dates, obeyed [Q.sub.CO,total] = (2.07 [+ or -] 0.20) x [10.sup.30] [R.sup.-1.66 [+ or -] 0.22.sub.h] molecules [s.sup.-1]. This heliocentric dependence was consistent with that found for water ([Q.sub.[H.sub.2]O] [alpha] [R.sup.-1.88 [+ or -] 0.18.sub.h] between 0.93 and 1.49 AU) and for mm-sized dust ([R.sup.-1.7 [+ or -] 0.2.sub.h] between 0.9 and 2.5 AU). Our derived total mixing ratio for CO was [Q.sub.CO,total]/[Q.sub.[H.sub.2]O] = 0.241 [+ or -] 0.009, with native and distributed sources each contributing an abundance of approximately 12 percent that of water. This was the case even after correcting measured CO and [H.sub.2]O column densities, and hence production rates, for opacity in the solar pump. The distributed source exhibited behavior consistent with thermal destruction of a precursor material. The observed variations in its production rate and spatial distribution along the slit suggested contributions from both a diffuse source in the coma and possibly from one or more jets enriched in CO or CO-containing material, such as CHON grains. Key Words: comets; ices; infrared spectroscopy; carbon monoxide; extended emission.

Hydrogen cyanide (HCN) was detected in Comet Hale-Bopp at infrared wavelengths near 3.0 (mu)m 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 rate on April 29.9 was (3.09 +/- 0.13) x 10(super 28) molecules s(super -1). When compared with the water production rate obtained from direct measurements of the H(sub 2)O 100-010 band on common observation dates using the same instrument and data processing algorithms, the weighted average (for the four dates) of the relative abundance (HCN/H(sub 2)O) was (0.40 +/- 0.05)%. The measured spatial distribution for HCN is consistent with its release at the nucleus - no significant contribution from a distributed source is required within 10,000 km of the nucleus. Key Words: comets, Hale-Bopp; composition; infrared observations; hydrogen cyanide.

Observations of comet Hale-Bopp using the cryogenic echelle grating spectrometer on the NASA IRTF 3-m telescope at Mauna Kea Observatory, Hawaii, indicate that around half of the carbon monoxide (CO) in the comet comes directly from ice stored in the nucleus. It has been established that the onset of distributed CO emission cannot be attributed to increased dust production alone. It is likely that a threshold, probably thermal, is reached for release of additional CO in the coma.

Water ([H.sub.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.sub.2]O itself. Production rates and rotational temperatures were measured, and the derived heliocentric dependence for the water production rate is [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] molecules [s.sup.-1] The spatial distribution of [H.sub.2]O molecules in the coma is consistent with water being released directly from the nucleus within 1.5 AU of the Sun, although release of a small fraction from icy grains cannot be excluded. When our derived water production rates are compared to the production of native carbon monoxide and dust, we obtain a dust to ice mass ratio of 5.1 [+ or -] 1.2 within a heliocentric distance of 1.5 AU. The abundance of [H.sub.2]O provides a benchmark for the volatile inventory in Hale--Bopp and, when compared to interstellar and nebular material, helps constrain the origin of cometary ices and their processing histories. These production rates derived from the direct detection of [H.sub.2]O provide a sound basis with which water production rates inferred by indirect methods can be compared. Key Words: comets; Hale--Bopp; composition; infrared observations; water.

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 [v.sub.3] fundamental band near 4.85 [[micro]meter] 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 detected directly through emission lines of its [v.sub.1]-[v.sub.2] hot band on UT April 16.0, April 30.0, and May 1.2, with a rotational temperature of 93 [+ or -] 16 K on May 1.2. Adopting a rotational temperature of 100 K for OCS, our derived production rates are (3.80 [+ or -] 0.67) and (1.77 [+ or -] 0.85) x [10.sup.28] molecules [s.sup.-1] on April 16.0 and May 1.2, respectively. The measured production rates imply mixing ratios ([Q.sub.OCS]/[Q.sub.[H.sub.2]]O) of (4.58 [+ or -] 0.77) and (2.76 [+ or -] 1.34) x [10.sup.-3] on April 16.0 and May 1.2, respectively. Comparison of spatial profiles for OCS, [H.sub.2]O, and the dust continuum derived from spectra taken less than 1 h apart suggests that on April 16.0 a significant amount of OCS ([approximately]70% of the total) was released as an extended source. On April 30.0 and May 1.2 the quality of the data prevent a firm conclusion regarding an extended source contribution. If the nature of the OCS source did not change between April 16.0 and May 1.2, the weighted mean mixing ratio is (4.13 [+ or -] 0.77) x [10.sup.-3] We searched for lines P1 through P8 of the [v.sub.3] band of OCS in Comet Hyakutake (C/1996 B2) on UT March 24.5, 1996. Our upper limit (3[Sigma]) for the OCS production rate in Hyakutake is 1.0 x [10.sup.27] molecules [s.sup.-1] ([Q.sub.OCS]l[Q.sub.[H.sub.2]O] [less than] 5.3 x [10.sup.-3]). Key Words: comets; spectroscopy; infrared; carbonyl sulfide; production rates.