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At least 379 records · Page 21

CO (v = 1-0) emission in the molecular shock regions of OMC-1

Using the new Aerospace spectrometer on the Kuiper Airborne Observatory, we have obtained observations of the molecular shocks associated with OMC-1. Unexpectedly these observations reveal (b = 1-0) emission from CO at 4.6 microns superposed on a strong continuum. Our observations strongly suggest that both the emission feature and the continuum are produced in molecular shocks. Since the (v = 1-0) band of CO is only excited in high-velocity shocks, we may be observing for the first time the primary driving mechanism in these regions. Even if these features are produced by scattering, the characteristics will provide new constraints on the conditions in and the geometry of the shock regions.

Grasdalen, G. L.↗

Stressed and unstressed Ge:Ga detector arrays for airborne astronomy

The construction and operation of 2D arrays of both unstressed and stressed Ge:Ga photoconductive detectors for far-IR astronomy from the Kuiper Airborne Observatory is presented. The 25 element (5 x 5) arrays are designed for a new cryogenically cooled spectrometer. The 2D spatial array described has the advantage of absolute registry between pixels in a map.

Stacey, G. J.↗

Nature and history of the organic compounds in comets - An astrophysical view

The chemical similarities between comets, carbonaceous chondrites, and interstellar molecules and grains are reviewed first. The evolution of frosty interstellar grains is then followed during the collapse of a molecular cloud fragment and the subsequent formation of the Solar System. The paradigm clarifies the probable origin of the two populations of comets of different symmetry (the Oort Cloud and the Kuiper Belt) and implies an exogenous origin for all carbon and water on earth. This origin is explained by the orbital diffusion of planetesimals that is required by the growth of protoplanets.

Delsemme, A. H.↗

Comets at the solar system's edge

The recent discovery of an object bound to the sun by gravity but situated beyond the orbit of Pluto is discussed. The discovery of this object, designated 1992 QB1, may confirm the existence of the Kuiper belt, envisioned to be a disk of far-flung comets left over from the origin of the solar system. The implications of the new discovery for the future search for distant comets beyond Pluto are examined.

Weissman, Paul R.↗

158 micron forbidden C II mapping of NGC 6946 - Probing the atomic medium

A well-sampled map (23 x 17 kpc) of the strong 158 micron forbidden C II cooling line in the Scd galaxy NGC 6946 at 55 arcsec resolution is presented which was taken with the MPE/UCB Far-infrared Imaging Fabry-Perot Interferometer (FIFI) in the Kuiper Airborne Observatory. It is concluded that the line emission in NGC 6946 is present in three spatially distinct components including nucleus, spiral arms, and extended region. An extended emission region is a source of most of the forbidden C II luminosity in NGC 6946. The 1 arcmin nuclear component has a line luminosity of 1.5 x 10 exp 7 solar luminosity and contributes 0.15 percent of the galaxy's total FIR luminosity. An extended component of forbidden C II emission is found to exist past the molecular extent of the galaxy and to be present to at least the full dimensions of the map. This component is attributed to a mixture of neutral and atomic clouds.

Madden, S. C.↗

Effect of jet engine exhaust on SOFIA straylight performance

The Stratospheric Observatory For Infrared Astronomy (SOFIA) is being designed at NASA's Ames Research Center as a replacement for the Kuiper Airborne Observatory (KAO). A 2.5-m Nasmyth telescope will be mounted in a Boeing 747 SP and flown at 41,000 ft, above most of the H2O in the earth's atmosphere. In the original SOFIA design, the telescope is located in front of the wings, as it is in the KAO. An alternative design with the telescope placed behind the wings is being studied as part of an effort to reduce cost and weight. In this location, the emission from the engines and the hot H2O molecules in the exhaust become significant straylight sources. The engines and exhaust radiate into the telescope cavity, and illuminate the primary and tertiary mirrors at low telescope elevation angles. The APART/PADE program was used to analyze the straylight at the SOFIA focal plane as a function of wavelength and telescope elevation angle. The emission from the engines and exhaust gas is compared to that from the earth and the telescope itself. Based on the results of this analysis, the SOFIA telescope has been moved behind the wings.

St. Clair Dinger, Ann↗

Submillimeter studies of main-sequence stars

JCMT maps of the 800-micron emission from Vega, Fomalhaut, and Beta Pictoris are interpreted to indicate that they are not ringed by large reservoirs of distant orbiting dust particles that are too cold to have been detected by IRAS. A search for 800-micron emission from stars in the Pleiades and Ursa Majoris open clusters is reported. In comparison with the mass of dust particles near T Tauri and Herbig Ae stars, the JCMT data indicate a decline in dust mass during the initial 3 x 10 exp 8 yr that a star spends on the main sequence that is at least as rapid as (time) exp -2. It is estimated that in the Kuiper belt the ratio of total mass carried by small particles to that carried by comets is orders of magnitude smaller than this ratio is 1 AU from the sun. If 800-micron opacities calculated by Pollack et al. (1993) are correct, then the particles with radii less than 100 microns that dominate the FIR fluxes measured by IRAS cannot entirely account for the measured 800-micron fluxes at Vega, Beta Pic, and Fomalhaut; larger particles must be present as well.

Zuckerman, B.↗

1981 Aeronautics and Space Highlights

This video presentation covers Shuttle flights 1 and 2, Spacelab, mobile workstation, Voyager 2 Saturn, Infrared Astronomy Satellite, Hubble Space Telescope, Kuiper Airborne Observatory, High Altitude Earth Survey, Landsat, aerodynamic research, electric cars, wind energy, XV-15, Quiet Shorthaul Research Aircraft, X-14 BVTOL, 40 x 80 Wind Tunnel, and turboprop research.

Source record↗

Thermal emission measurements (5-25 microns) of Hawaiian palagonitic soils with implications for Mars

The research presented here represents the initial phase of a broader project that is intended to provide data in the mid- and far-IR spectral region for both well-characterized iron oxides/oxyhydroxides and poorly crystalline or amorphous materials (e.g., palagonites). Such information can be used in the interpretation of data to be returned by the Mars Observer Thermal Emission Spectrometer (TES). Additionally, this same information will prove useful for assessing the information content of existing Kuiper Airborne Observatory, Mariner 7, and Mariner 9 spectra. which also cover the thermal IR wavelength region.

Bell, J. F., III↗

Airborne astronomy with a 150 micrometer - 500 micrometer heterodyne spectrometer

This report summarizes work done under NASA Grant NAG2-254 awarded to the University of California. The project goal was to build a far-infrared heterodyne spectrometer for NASA's Kuiper Airborne Observatory (KAO), and to use this instrument to observe atomic and molecular spectral lines from the interstellar medium. This goal was successfully achieved; the spectrometer is now in routine use aboard the KAO. Detections of particular note have been the 370 micrometers line of neutral atomic carbon, the 158 micrometers transition of ionized carbon, many of the high-J rotational lines of 12CO and 13CO between J=9-8 and J=22-21, the 119 micron ground-state rotational line of OH, and the 219 micron ground-state rotational line of H2D(+). All of these lines were observed at spectral resolutions exceeding 1 part in 10(exp 6), thereby allowing accurate line shapes and Doppler velocities to be measured.

Betz, A. L.↗

Airborne spectrophotometry of SN 1987A from 1.7 to 12.6 microns - Time history of the dust continuum and line emission

Spectrophotometric observations of SN 1987A from the Kuiper Airborne Observatory are presented for five epochs at 60, 260, 415, 615, and 775 days after the explosion. The low-resolution (lambda/Delta lambda = 50-100) spectra of SN 1987A are combined with data from other wavelengths to model the continuum, subtract the continuum from the spectra to determine line strengths and reveal molecular bands, separate the atomic continuum radiation from the dust continuum, and derive constraints on the grain temperatures and optical depths. A scenario for the evolution of SN 1987A and that of the ejecta from which it arises is obtained on the basis of the analysis of the continuum emission.

Wooden, Diane H.↗

The origin and role of dust in the early solar system

Dust was the primary building material of the solar nebula planetesimals that accumulated to form minor planets, solid planets, and the cores of giant planets. Collected interplanetary dust particle (IDP) samples probably contain preserved samples of nebular dust that formed over a wide range of radial distance. There are two general source regions of IDP's, the asteroid belt and the short-period comets. The collected asteroid particles are likely to be rather representative samples of material that accreted into planetesimals in the 2.2 to 3.3 AU region. The comet samples are likely to be representative samples of grains that accreted in the Kuiper belt region between 20 AU and some hundreds of AU. Many of the solar system effects on grains should have been more pronounced or even restricted to the less than 5 AU region where the asteroids were formed. A major goal of IDP research is to try to identify typical asteroidal and cometary IDP's and to study their properties. If successful this will provide fundamental insight into both the initial solids in the solar nebula and materials modified by a variety of important nebular processes.

Brownlee, Don E.↗

Far-infrared mapping of dusty elliptical galaxies

Preliminary results from a program to map the thermal far-infrared emission from cool dust in elliptical galaxies using the Yerkes 60-Channel Camera on the Kuiper Airborne Observatory (KAO) are presented. The 160 micron emission from the elliptical NGC 6542 is apparently extended over the optical galaxy whereas the 100 micron emission is unresolved. This implies a dust temperature gradient consistent with that expected for dust with Galactic properties exposed to the general interstellar radiation field of the elliptical galaxy. Observations of the elliptical NGC 5666 and the NGC 7463/4/5 compact group (consisting of the elliptical NGC 7464, the S0 NGC 7465, and the spiral NGC 7463) are also discussed.

Lees, Joanna F.↗

Comprehension and retrieval of failure cases in airborne observatories

This paper describes research dealing with the computational problem of analyzing and repairing failures of electronic and mechanical systems of telescopes in NASA's airborne observatories, such as KAO (Kuiper Airborne Observatory) and SOFIA (Stratospheric Observatory for Infrared Astronomy). The research has resulted in the development of an experimental system that acquires knowledge of failure analysis from input text, and answers questions regarding failure detection and correction. The system's design builds upon previous work on text comprehension and question answering, including: knowledge representation for conceptual analysis of failure descriptions, strategies for mapping natural language into conceptual representations, case-based reasoning strategies for memory organization and indexing, and strategies for memory search and retrieval. These techniques have been combined into a model that accounts for: (a) how to build a knowledge base of system failures and repair procedures from descriptions that appear in telescope-operators' logbooks and FMEA (failure modes and effects analysis) manuals; and (b) how to use that knowledge base to search and retrieve answers to questions about causes and effects of failures, as well as diagnosis and repair procedures. This model has been implemented in FANSYS (Failure ANalysis SYStem), a prototype text comprehension and question answering program for failure analysis.

Alvarado, Sergio J.↗

Is H20 present on Io? The detection of a new strong band near 3590/cm (2.79 micrometer)

A strong absorption band at 3590 +/- 20/cm (2.790 +/- 0.015 microns) has been discovered in the spectrum of Io using the Kuiper Airborne Observatory (KAO). The 2 nu(sub 1) + nu(sub 3) comination mode of solid SO2 falls at this position. Since SO2 is abundant on Io it must contribute to the new band. However, a band due to H2O was predicted near this frequency in Io's spectrum based on laboratory experiments of H2O:SO2 mixed Io ice analogs which were used to assign the two weak, variable features at 3370 and 3170/cm (2.97 and 3.15 microns) to trace amounts of H2O frozen in solid SO2 on Io. The new band probably originates from both SO2 and H2O. Unfortunately, the spectral resolution of the data is insufficient to settle the issue of whether there are two resolvable components.

Salama, F.↗

NASA's initiative to develop education through astronomy (IDEA)

We describe a progressive program in science education called the Initiative to Develop Education through Astronomy (IDEA). IDEA represents a commitment by the Astrophysics Division of NASA Headquarters to pre-collegiate and public learning. The program enlists the full participation of research astronomers in taking advantage of the natural appeal of astronomy and the unique features of space astrophysics missions to generate valuable learning experiences and scientifically accurate and educationally effective products for students, teachers and citizens. One of the premier projects is called Flight Opportunities for Science Teacher EnRichment (FOSTER) - a program to fly teachers aboard the Kuiper Airborne Observatory during actual research missions. IDEA is managed by a visiting scientist with extensive educational background (each of the authors have served in this role), and the program is unique within NASA science divisions for having a full time scientist devoted to education. IDEA recognizes that the rapidly shifting social and political landscape has caused a fundamental change in how science is expected to contribute to society. It is in the enlightened self-interest of all research scientists to respond to the challenge of connecting forefront research to basic educational needs. IDEA is exploring the avenues needed to facilitate these connections, including supplementing research grants for educational purposes.

Bennett, Jeffrey O.↗

Is H2O present on Io? The detection of a new strong band near 3590/cm (2.79 microns)

A strong absorption band at 3590 +/- 20/cm (2.790 +/- 0.015 microns) has been discovered in the spectrum of Io using the Kuiper Airborne Observatory (KAO). The 2nu(sub 1) + nu(sub 3) combination mode of solid SO2 falls at this position. Since SO2 is abundant on Io it must contribute to the new band. However, a band due to H2O was predicted near this frequency in Io's spectrum based on laboratory experiments of H2O:SO2 mixed Io ice analogs which were used to assign the two weak, variable features at 3370 and 3170/cm (2.97 and 3.15 microns) to trace amounts of H2O frozen in solid SO2 on Io. The new band probably originates from both SO2 and H2O. Unfortunately, the spectral resolution of the data is insufficient to settle the issue of whether there are two resolvable components.

Salama, F.↗