Physics
Scientific paper
Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufm.p31b1420g&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #P31B-1420
Physics
3630 Experimental Mineralogy And Petrology, 3934 Optical, Infrared, And Raman Spectroscopy, 5470 Surface Materials And Properties, 6250 Moon (1221), 6297 Instruments And Techniques
Scientific paper
We measured reflectance spectra of common lunar minerals spanning wavelengths from the visible to the far-infrared. These measurements provided critical data related to spectral variability of lunar minerals relevant to the Diviner lunar radiometer Compositional Investigation. Diviner will launch in early 2009 onboard the Lunar Reconnaissance Orbiter (LRO). Diviner is a nine-channel radiometer designed to study the thermal-physical and compositional properties of the lunar surface. Diviner has two solar channels (0.35- 2.8 μm; high / low sensitivity), three '8-micron' channels (7.55-8.05, 8.10-8.40, and 8.40-8.70 μm), and four thermal channels (13-23, 25-41, 50-100, 100-200 μm). The Diviner Compositional Investigation will use the 8-micron channels to determine the location of the Christiansen Feature, which is a good compositional indicator. The Christiansen Feature has a systematic behavior for silicates and shifts to longer wavelengths with increasing polymerization of the Si-04 tetrahedra. Therefore, the Christiansen Feature is located at shorter wavelengths for more felsic materials and longer wavelengths for more mafic materials. Additional compositional constraints will be gained using bulk solar albedo from solar channel data and spectral variation of thermal channels data. Even at Diviner's far- infrared spectral resolution, differences between mineral spectra are evident. It was important to have competent laboratory spectra measured across all Diviner-sensitive wavelengths. The spectra presented were measured on a Bruker IFS66/V Fourier transform infrared spectrometer at the University of Oxford Atmospheric, Oceanic, and Planetary Physics Laboratory. In order to cover Diviner's 0.3-200 micron response, we used three sources (quartz-tungsten, Glowbar, and mercury-arc) and several beam splitters. The measurements included the most common lunar minerals quartz, anorthite, enstatite, augite, forsterite, fayalite, and ilmenite and additional minor minerals. The samples were crushed and dry-sieved to different grain size seperates (< 30, 30-64, 64-120, and 120-450 μm). These minerals were also mixed into several analog lunar rock compositions. The location of the Christiansen Feature for 64-120 μm seperates in low vacuum was measured as follows: quartz, 7.38 μm; anorthite, 8.03 μm; enstatite, 8.38 μm; augite, 8.42 μm; forsterite, 8.88 μm; and fayalite, 9.38 μm. It was observed that the shape of Christiansen Feature changed and the location shifted slightly with changes in grain size and sample camber pressure. Some minerals also showed variations in solar albedo with grain size. Understanding spectral variations in common lunar minerals is critical to the success of the Diviner Compositional Investigation. These measurements represent an important first step. Future studies will expand the measurements to include a simulated lunar environment (i.e. emission measurements in vacuum with a cold back shield).
Bowles Neil E.
Greenhagen Benjamin T.
Paige David A.
Thomas Ian
No associations
LandOfFree
Laboratory Visible to Far-Infrared Measurements in Support of the 2009 LRO Diviner Lunar Radiometer Compositional Investigation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Laboratory Visible to Far-Infrared Measurements in Support of the 2009 LRO Diviner Lunar Radiometer Compositional Investigation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laboratory Visible to Far-Infrared Measurements in Support of the 2009 LRO Diviner Lunar Radiometer Compositional Investigation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1237260