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We investigate the density and spatial distribution of the H2 exosphere of the Moon assuming various source mechanisms. Owing to its low mass, escape is non-negligible for H2. For high-energy source mechanisms, a high percentage of the released molecules escape lunar gravity. Thus, the H2 spatial distribution for high-energy release processes reflects the spatial distribution of the source. For low...
Simultaneous measurements of helium in the exosphere of the Moon are made from the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP) and the Lunar Atmosphere and Dust Environment Explorer (LADEE) Neutral Mass Spectrometer (NMS) through the entire 5-month span of the LADEE mission. In addition, the ARTEMIS mission monitored the solar wind alpha particle flux to the Moon. Modeling...
The clear angular separation of Pluto and Charon from ground-based telescopes has been enabled by improved technology, particularly adaptive optics systems. Near-infrared spectral data have revealed Charon’s surface to be rich in crystalline water ice and ammonia hydrates. In this work, we search for spectral differences across Charon’s surface with new near-infrared spectral data taken in the K-band...
We report on a multi-year dataset of daily averaged observations of He in the lunar atmosphere by the LAMP UV spectrograph on NASA’s Lunar Reconnaissance Orbiter (LRO). We examine data obtained from the start of the LRO orbital tour in September 2009 to March 2013. We find that the maximum He number density occurs about two hours after local midnight, which is consistent with earlier measurements...
We report on the detection of H2 as seen in our analysis of twilight observations of the lunar atmosphere observed by the LAMP instrument aboard NASA’s Lunar Reconnaissance Orbiter. Using a large amount of data collected on the lunar atmosphere between September 2009 and March 2013, we have detected and identified, the presence of H2 in the native lunar atmosphere, for the first time. We derive a...
We report on our analysis of twilight observations of the lunar atmosphere as observed by the LAMP instrument aboard NASA’s Lunar Reconnaissance Orbiter. Using data collected between September 2009 and March 2013, we have examined over 7.7millions of integration time obtained when the surface was in darkness, but the atmosphere between the spacecraft and the surface was in sunlight. Using these data,...
The spectra of water ice on the surfaces of icy satellites and Kuiper Belt Objects (KBOs) indicate that the surface ice on these bodies is in a crystalline state. This conflicts with theoretical models, which predict that radiation (galactic cosmic rays and solar ultraviolet) should damage the crystalline structure of ice on geologically short timescales. Temperatures are too low in the outer Solar...
We investigate the internal thermal evolution of Kuiper belt objects (KBOs), small (radii <1000 km), icy (mean densities <2500kgm−3) bodies orbiting beyond Neptune, focusing on Pluto's moon Charon in particular. Our calculations are time-dependent and account for differentiation. We review evidence for ammonia hydrates in the ices of KBOs, and include their effects on the thermal evolution....
We observed Pluto and Triton with the CSHELL echelle spectrograph on the Infrared Telescope Facility in April and July 1996, in an effort to detect the R(2), R(3), and R(4) rotational lines of the 2-0 vibrational transition of gaseous CO. As no lines were detected, we derived 3-σ upper limits on the average widths of these three lines of 0.040 cm -1 for Pluto and 0.028 cm -1...
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