Photometry of the comet 2060 Chiron

The comet 2060 Chiron has proven to be an interesting and enigmatic object. Situated between the orbits of Saturn and Uranus, it was originally classified as the most distant asteroid. It began to show cometary behavior in 1987 by increasing a full magnitude in brightness and developing a coma; there is evidence also for similar earlier outbursts. A thorough study of Chiron is important for two reasons: (1) it is a transition object defining the relationship between comets, asteroids, and meteorites; and (2) a full description of its changes in brightness - particularly on time scale of hours - will provide an empirical foundation for understanding the physical mechanisms (including outgassing, sublimation of volatiles, and even significant mass ejections) driving the evolution of comets. Short term outbursts were observed in early 1989, and a rapid decrease in brightness of Chiron's coma was observed in 1990 in the V and R filters. Also, a rotational lightcurve was detected of the nucleus with an amplitude only 1/4 that observed in its quiescent state: this fact indicates the increased importance of the optically thin coma to the observed brightness

Disk resolved studies of the optical properties and physical nature of the surfaces of the outer planet satellites

The spatially resolved albedo, color, compaction state, roughness, and constituent particle sizes of the surfaces of the satellites of Saturn, Uranus, and Jupiter provide important constraints in understanding the geologic evolution and relevant exogenic processes operating in these satellite systems. Some details of observations are given

Broadband Photometry of Pluto

Broadband Photometry was obtained to provide data on Pluto, discovered on January 23, 1930 by Clyde W. Tombaugh at Lowell Observatory in Flagstaff, Arizona. Our data was collected over a series of four nights of time-resolved Bessel BVRI photometry using the 0.6-m telescope at the JPL Table Mountain Observatory (TMO) located in Wrightwood, California. Our collected data will complement the data obtained by the New Horizons mission to calculate Pluto’s solar phase curve at opposition. The primary objective of our work will be to analyze the solar phase curve of Pluto while it is at opposition. Our work will help in understanding Pluto. It will also provide evidence for seasonal transportation of volatiles within Pluto’s atmosphere. Our data will be analyzed through various programs, where we will use both biases and sky-flats to make any correction to the images of Pluto we’ve obtained (i.e debris). Once we have analyzed the data, we will be able to calculate and plot Pluto’s solar phase curve. Our data will be used to complement the data obtained by the New Horizons mission and possibly answer questions regarding the seasonal transport of volatiles as found on Pluto, as well as the albedo patterns

Detecting Seasonal Volatile Transport on Triton through Photometric Observations

More than 35 million people in the western United States depend on the Colorado River as a Broadband Photometry will be obtained to provide data on Triton. Our data will be collected over a series of nights of time-resolved Bessel BVRI photometry using the 0.6-m telescope at the JPL Table Mountain Observatory (TMO) located in Wrightwood, California. The objective of these observations is to detect and measure volatile transport on Triton. The vapor pressures of nitrogen and methane vary over the seasonal cycles of Triton and Pluto. The seasonal migration of frost can be detected by a combination of changes in the rotational lightcurve. Previous work of Triton has shown that these exhibit the transport of volatiles on their surfaces. The purpose of acquiring another lightcurve is to determine whether volatile transport is still occurring and to track it. Our current goal is to fill in the missing longitudes that we not obtained during our last observations of Triton. Our previous work detected an opposition surge for the first time, and these observations will allow us to further characterize it. Our goal is to create detailed and longer-term comparisons of our data with Voyager images and other volatile-transport models. With our measurements and ground-based data of Pluto and Triton, we will hopefully have a greater understanding of seasonal volatile transport on Kuiper Belt Objects. This understanding will help us predict, search for, model, and possibly observe seasonal changes on other Kuiper Belt Objects

Preflare observations using the Skylab X-ray telescope

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences.Microfiche copy available in Archives and Science.Bibliography : leaves 57-58.by Bonnie J. Buratti.M.S

Evidence of Titan's Climate History from Evaporite Distribution

Water-ice-poor, 5-$\mu$m-bright material on Saturn's moon Titan has previously been geomorphologically identified as evaporitic. Here we present a global distribution of the occurrences of the 5-$\mu$m-bright spectral unit, identified with Cassini's Visual Infrared Mapping Spectrometer (VIMS) and examined with RADAR when possible. We explore the possibility that each of these occurrences are evaporite deposits. The 5-$\mu$m-bright material covers 1\% of Titan's surface and is not limited to the poles (the only regions with extensive, long-lived surface liquid). We find the greatest areal concentration to be in the equatorial basins Tui Regio and Hotei Regio. Our interpretations, based on the correlation between 5-$\mu$m-bright material and lakebeds, imply that there was enough liquid present at some time to create the observed 5-$\mu$m-bright material. We address the climate implications surrounding a lack of evaporitic material at the south polar basins: if the south pole basins were filled at some point in the past, then where is the evaporite

Geomorphological significance of Ontario Lacus on Titan: Integrated interpretation of Cassini VIMS, ISS and RADAR data and comparison with the Etosha Pan (Namibia)

International audienceOntario Lacus is the largest lake of the whole southern hemisphere of Titan, Saturn's major moon. It has been imaged twice by each of the Cassini imaging systems (Imaging Science Subsystem (ISS) in 2004 and 2005, Visual and Infrared Mapping Spectrometer (VIMS) in 2007 and 2009 and Radar in 2009 and 2010). In this study, we take advantage of each imaging dataset to establish a global survey of Ontario Lacus' environment from 2005 to 2010. We perform a geomorphological mapping and interpretation of Ontario Lacus, mainly based on a joint analysis of VIMS and Radar SAR datasets, along with the T49 altimetric profile acquired in December 2008. The morphologies observed on Ontario Lacus are compared to landforms of a semi-arid terrestrial analog, which closely resembles Titan's lakes: the pans of the Etosha Basin, located in Namibia. From this comparison, we infer that Ontario Lacus is an extremely flat depression where liquids, only located in the darkest areas in the Radar data, cover topographic lows where the "alkanofer" would raise above the depression floor. The rest of the depression appears rather as a muddy flat surface likely composed of a thick coating of photon-absorbing materials, explaining its still rather dark appearance in the infrared and radar data. We also determined whether surface changes occurred during the 5 years time interval between 2005 and 2010. We found that the depression contour is constant at the resolution of ISS and VIMS data, both being consistent with the depression contour derived from the Radar data. Our interpretation, in which the liquids are located only in some parts of Ontario Lacus, agrees with the lack of significant change of the depression contour between 2007 (and 2005 with more uncertainties) and 2010

Composition of Near-Earth Asteroid 2008 EV5: Potential target for Robotic and Human Exploration

We observed potentially hazardous asteroid (PHA) 2008 EV5 in the visible (0.30-0.92 microns) and near-IR (0.75-2.5 microns) wavelengths to determine its surface composition. This asteroid is especially interesting because it is a potential target for two sample return mission proposals (Marco Polo-R and Hayabusa-2) and human exploration due to its low delta-v for rendezvous. The spectrum of 2008 EV5 is essentially featureless with exception of a weak 0.48-microns spin-forbidden Fe3+ absorption band. The spectrum also has an overall blue slope. The albedo of 2008 EV5 remains uncertain with a lower limit at 0.05 and a higher end at 0.20 based on thermal modeling. The Busch et al. (2011) albedo estimate of 0.12 is consistent with our thermal modeling results. The albedo and composition of 2008 EV5 are also consistent with a C-type taxonomic classification (Somers et al. 2008). The best spectral match is with CI carbonaceous chondrites similar to Orgueil, which also have a weak 0.48-microns feature and an overall blue slope. This 0.48-microns feature is also seen in the spectrum of magnetite. The albedo of CI chondrites is at the lower limit of our estimated range for the albedo of 2008 EV5.Comment: Pages: 19 Figures: 6 Tables: