7 research outputs found
IUE program SUGSD: Varability time scale of H Ly-alpha from Uranus
The scientific motivation for this program was to determine the time scale for the variability of the H Lyman-alpha emission from Uranus. The purpose of this series of observation is to determine its variability on shorter time scales. A series of observations was carried out in coordination with ESA to cover as completely as possible one 24 hour period of the Uranian H Lyman-alpha emission. The observations were obtained on April 23 and 24. Two additional ovservations on April 25 and 26 were obtained to search for longer term trends. A small modulation in the brightness was observed and the results presented
Far-ultraviolet Spectroscopy of Venus and Mars at 4 A Resolution with the Hopkins Ultraviolet Telescope on Astro-2
Far-ultraviolet spectra of Venus and Mars in the range 820-1840 A at 4 A
resolution were obtained on 13 and 12 March 1995, respectively, by the Hopkins
Ultraviolet Telescope (HUT), which was part of the Astro-2 observatory on the
Space Shuttle Endeavour. Longward of 1250 A, the spectra of both planets are
dominated by emission of the CO Fourth Positive band system and strong OI and
CI multiplets. In addition, CO Hopfield-Birge bands, B - X (0,0) at 1151 A and
C - X (0,0) at 1088 A, are detected for the first time, and there is a weak
indication of the E - X (0,0) band at 1076 A in the spectrum of Venus. The B -
X band is blended with emission from OI 1152. Modeling the relative intensities
of these bands suggests that resonance fluorescence of CO is the dominant
source of the emission, as it is for the Fourth Positive system. Shortward of
Lyman-alpha, other emission features detected include OII 834, OI lambda 989,
HI Lyman-beta, and NI 1134 and 1200. For Venus, the derived disk brightnesses
of the OI, OII, and HI features are about one-half of those reported by Hord et
al. (1991) from Galileo EUV measurements made in February 1990. This result is
consistent with the expected variation from solar maximum to solar minimum. The
ArI 1048, 1066 doublet is detected only in the spectrum of Mars and the derived
mixing ratio of Ar is of the order of 2%, consistent with previous
determinations.Comment: 8 pages, 5 figures, accepted for publication in ApJ, July 20, 200
Design And Operation Of The Hopkins Ultraviolet Telescope
The Hopkins Ultraviolet Telescope (HUT) was flown aboard the Space Shuttle Columbia for 9 days in December 1990 and the Space Shuttler Endeavour for 17 days in March 1995. Spectrophotometric observations of numerous astronomical sources were made throughout the far ultraviolet (912-1850 angstrom) at a resolution of approx. 3 angstrom, and for some sources, in the extreme ultraviolet (415-912 angstrom) at a resolution of approx. 1.5 angstrom. Overall, significant results were obtained
Dr. Samuel T. Durrance
Dr. Samuel T. Durrance
Professor, Physics and Space Sciences, Florida Institute of Technology
Samuel T. Durrance was born in Tallahassee. He received a Bachelor of Science degree and a Master of Science degree in physics (with honors), at California State University, Los Angeles, 1972 and 1974, respectively, and a doctorate in astro-geophysics at the University of Colorado at Boulder in 1980. Dr. Durrance has been involved in space exploration, scientific research and education for over 30 years. He has logged over 615 hours in space as a payload specialist and member of the crew of Space Shuttle Columbia for the STS-35/Astro-1 and Space Shuttle Endeavour for the STS-67/Astro-2 missions. He played several key roles in the design, construction, integration, and operation of the Hopkins Ultraviolet Telescope and NASA’s Astro Observatory. He conducted research and directed graduate students at the Johns Hopkins University for 16 years. He has designed and built spectrometers, detectors, and imaging systems, and made numerous spacecraft and ground-based astronomical observations. He conceived and directed a program to develop adaptive-optics instrumentation for ground based astronomy. He led the team that designed and built the Adaptive Optics Coronagraph, which led to the discovery of the first cool brown dwarf, Gliese 229 b, orbiting a nearby star. He also co-discovered a tell-tale signature of planet formation in the dust disk surrounding the star beta Pictoris.
Starting in 2001, Durrance was the executive director of the Florida Space Research Institute (FSRI) created by the State of Florida in 2000. FSRI was located at NASA’s Kennedy Space Center in support of the State’s Space Life Sciences Laboratory. Since 2006, he has been a professor of physics and space sciences at the Florida Institute of Technology. At Florida Tech he is developing an interdisciplinary research program and undergraduate degree program in astrobiology. His long-term goal at Florida Tech is to create a climate where students and faculty can regularly participate in space-based research programs. His research interests include the origin and evolution of the solar system, the search for planets around other stars, planetary astronomy, atmospheric physics, nuclear physics, adaptive optics, spacecraft operations, and the origin of life. He has published over 100 technical papers on planetary astronomy, adaptive optics, atmospheric physics, nuclear physics, and spacecraft operations.https://commons.erau.edu/space-congress-bios-2016/1069/thumbnail.jp