Mid-IR Spectra of HED Meteorites and Synthetic Pyroxenes: Reststrahlen Features (9-12 micron)

In an earlier study. Hamilton (2000) mapped the behavior of the 9-12 micron reststrahlen structures with composition in a suite of primarily natural terrestrial pyroxenes. Here we examine the same set of reststrahlen features in the spectra of diogenites and eucrites and place them in the context of the terrestrial samples and of a suite of well-characterized synthetic pyroxenes. The results will be useful to the interpretation of mid-IR spectra of 4 Vesta and other basaltic asteroids

Diogenite-like Features in the Spitzer IRS (5-35 micrometers) Spectrum of 956 ELISA

We report preliminary results from the Spitzer Infrared Spectrograph (IRS) observations of the V-type asteroid 956 Elisa. Elisa was observed as part of a campaign to measure the 5.2-38 micron spectra of small basaltic asteroids with the Spitzer IRS. Targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vesroids"), several outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid 4055 Magellan

The Near-Earth Encounter of 2005 YU55: Thermal Infrared Observations from Gemini North

As part of a multi-observatory campaign to observe 2005 YU55 during its November 2011 encounter with the Earth, thermal infrared photometry and spectroscopy (7.9- 14 and 18-22 micron) were conducted using the Michelle instrument at Gemini North. Reduction of the 8.8 flm photometry and the spectroscopy from UT Nov-IO as well as of all the Gemini data from UT Nov-9 is in progress. Results will be discussed

Spitzer IRS Spectra of Basaltic Asteroids: Preliminary Results

We present preliminary results of a Spitzer program to observe the 5.2--38 micron spectra of small basaltic asteroids using the Spitzer IRS (Infrared Spectrograph). Our targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vestoids"), four outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid (NEA) 4055 Magellan. We will compare the compositions and thermophysical properties of the non-Vestoid objects with those of the dynamical vestoids to provide insight on the extent of metal-silicate differentiation on planetsimals during the epoch of planet formation in the early Solar System. As of this writing, spectra of asteroids 10537 (1991 RY16) and 2763 Jeans have been returned. Analysis of these data are ongolng. Observations of 956 Elisa, 2653 Principia, 4215 Kamo, 7472 Kumakiri, and 1459 Magnya have been scheduled and are expected to be available by the time of the DPS meeting. NIR spectra and lightcurves o f the target asteroids are also being observed in support of this program

The Near-Earth Encounter of Asteroid 308635 (2005 YU55): Thermal IR Observations

The near-Earth approach (0.00217 AU, or 0.845 lunar distances) of the C-type asteroid 308635 (2005 YU55) in November 2011 presented a rare opportunity for detailed observations of a low-albedo NEA in this size range. As part of a multi-telescope campaign to measure visible and infrared spectra and photometry, we obtained mid-infrared (approx. 8 to 22 micron) photometry and spectroscopy of 2005 YU55 using Michelle on the Gemini North telescope on UT November 9 and 10,2011. An extensive radar campaign together with optical light-curves established the rotation state of YU55. In addition, the radar imaging resulted in a shape model for the asteroid, detection of numerous boulders on its surface, and a preliminary estimate of its equatorial diameter at 380 +/- 20 m. In a preliminary analysis, applying the radar and lightcurve-derived parameters to a rough-surface thermophysical model fit to the Gemini/Michelle thermal emission photometry results in a thermal inertia range of approximately 500 to 1500 J/sq m/0.5s/K, with the low-thermal-inertia solution corresponding to the small end of the radar size range and vice versa. Updates to these results will be presented and modeling of the thermal contribution to the measured near-infrared spectra from Palomar/Triplespec and IRTF/SpeX will also be discussed

Future Planetary Instrument Capabilities Made Possible by Micro- and Nanotechnology

A number of new instrument capabilities are currently in maturation for future in situ use on planetary science missions. Moving beyond the impressive in situ instrumentation already operating in planetary environments beyond Earth will enable the next step in scientific discovery. The approach for developing beyond current instrumentation requires a careful assessment of science-driven capability advancement. To this end, two examples of instrument technology development efforts that are leading to new and important analytical capabilities for in situ planetary science will be discussed: (1) an instrument prototype enabling the interface between liquid separation techniques and laser desorption/ionization mass spectrometry and (2) an addressable excitation source enabling miniaturized electron probe microanalysis for elemental mapping of light and heavy elements

Role of 5-HT1A-mediated upregulation of brain indoleamine 2,3 dioxygenase 1 in the reduced antidepressant and antihyperalgesic effects of fluoxetine during maintenance treatment

The reduced antidepressant and antihyperalgesic effects of selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine during maintenance treatment has been reported, but little is known about the molecular mechanism of this phenomenon. In three comorbid pain and depression animal models (genetic predisposition, chronic social stress, arthritis), we showed that the fluoxetine’s antidepressant and antihyperalgesic effects were reduced during the maintenance treatment. Fluoxetine exposure induced upregulation of the 5-hydroxytryptamine 1A (5-HT1A) auto-receptor and indoleamine 2,3 dioxygenase 1 (IDO1, a rate-limiting enzyme of tryptophan metabolism) in the brainstem dorsal raphe nucleus (DRN), which shifted the tryptophan metabolism away from the 5-HT biosynthesis. Mechanistically, IDO1 upregulation was downstream to fluoxetine-induced 5-HT1A receptor expression because 1) antagonism of the 5-HT1A receptor with WAY100635 or 5-HT1A receptor knockout blocked the IDO1 upregulation, and 2) inhibition of IDO1 activity did not block the 5-HT1A receptor upregulation following fluoxetine exposure. Importantly, inhibition of either the 5-HT1A receptor or IDO1 activity sustained the fluoxetine’s antidepressant and antihyperalgesic effects, indicating that 5-HT1A-mediated IDO1 upregulation in the brainstem DRN contributed to the reduced antidepressant and antihyperalgesic effects of fluoxetine. These results suggest a new strategy to improving the therapeutic efficacy of SSRI during maintenance treatment

Widespread carbon-bearing materials on near-Earth asteroid (101955) Bennu

(101955) Bennu is a dark asteroid on an Earth-crossing orbit, thought to have assembled from the fragments of an ancient collision. We use spatially-resolved visible and near-infrared spectra of Bennu to investigate its surface properties and composition. In addition to a hydrated phyllosilicate band, we detect a ubiquitous 3.4-micron absorption feature, which we attribute to a mix of organic and carbonate materials. The shape and depth of this absorption feature vary across Bennu’s surface, spanning the range seen among similar main-belt asteroids. Its distribution does not correlate with temperature, reflectance, spectral slope, or hydrated minerals, although some of those characteristics correlate with each other. The deepest 3.4-micron absorptions occur on individual boulders. The variations may be due to differences in abundance, recent exposure, or space weathering