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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

First detection of the ground state JK = 1 sub 0 going to 0 sub 0 submillimeter transition of interstellar ammonia

The JK = 1 sub 0 approaching O sub 0 transition of ammonia at 572.5 GHz was detected in OMC-1 from NASA's Kuiper Airborne Observatory. The central velocity of the line (VLSR approximately = 9 km/s) indicates that it originates in the molecular cloud material, not the hot core. The derived filling factor of approximately 0.09 in a 2' beam implies a source diameter of approximately 35" if it is a single clump. This clump area is much larger than that derived from observations of the sub 1 inversion transition. The larger optical depth in the 1 sub 0 approaching 0 sub 0 transition (75-350) can account for the increased source area and linewidth as compared with those seen in the 1 sub 0 inversion transition.

Keene, J.↗
NASA NTRS1981

Far-infrared spectrophotometer for astronomical observations

A liquid-helium-cooled far infrared spectrophotometer was built and used to make low resolution observations of the continua of several kinds of astronomical objects using the Kuiper Airborne Observatory. This instrument fills a gap in both sensitivity to continuum sources and spectral resolution between the broadband photometers with lambda/Delta lambda approximately 1 and spectrometers with lambda/Delta lambda greater than 50. While designed primarily to study planetary nebulae, the instrument permits study of the shape of the continua of many weak sources which cannot easily be observed with high resolution systems.

Moseley, H.↗
NASA NTRS1981

InSb heterodyne receivers for submillimeter astronomy

InSb hot electron bolometer mixer receivers have been developed for submillimeter line studies of the interstellar medium up to about 500 GHz. The receivers have been used aboard the NASA Kuiper Airborne Observatory which is transported to about 12,000 km by a C141 aircraft. Data have been obtained on new interstellar lines (such as the ground-state fine structure transition of atomic carbon at 492 GHz) and such molecular transitions as carbon monoxide and water. Other data were obtained at ground level using the 5-cm Hale telescope at Mount Palomar and the NASA Infrared Telescope facility at Mauna Kea, HI. The heterodyne bolometers have reached noise temperatures of less than 400 K at all frequencies to 500 GHz.

Phillips, T. G.↗
NASA NTRS1982

Infrared observations of low-mass star formation in Orion - HH objects

The results of a preliminary analysis of IR data on Herbig-Haro objects in the Orion nebula are reported. The observations were made with the high angular resolution IR photometry equipment on the NASA Kuiper Airborne Observatory and the NASA facility on Mauna Kea, HI. Data were taken in the 1-200 microns region with 40, 6, and 8 arcsec resolution. Attention was focused on NGC 1999 (HH1-3) and M78 (HH24-25) and the determination of absolute luminosities of the exciting stars. Measurements were also made of the IR energy distribution in the thermally emitting dust clouds and the point sources. Herbig-Haro objects featured compact and far IR sizes and large visual extinction, in addition to a steeply rising energy distribution up to 50-100 microns, where the luminosity emitted was concentrated.

Harvey, P. M.↗
NASA NTRS1982

Infrared observations from the NASA Airborne Observatories

The results of observations made aboard the Kuiper Airborne Observatory, with its 91-cm telescope and the Lear Jet with its 30-cm system, are summarized, and instrumental advances accomplished for NASA aircraft facilities are described. Information has been obtained about the ring brightness of Saturn, a new broadband feature in carbon stars and two planetary nebulae, the temperature of dust globules, rotational transitions of CO in the Kleinmann-Low nebula, and far infrared emission from a quasar. Improvements in the minimum signals reported for photometry and spectrometry are described, and possibilities for improvements in the polarization, time resolution measurements, and in angular limitations are addressed.

Harwit, M.↗
NASA NTRS1982

New far infrared observations of the central 30 arcmin of the Galaxy

Observations of the 55 micron and 125 micron emissions of the central 30 arcmin of the Galaxy were performed with 1 arcmin resolution with instrumentation on-board the Kuiper flying observatory. The flux distributions detected showed both wavelengths with peaks near the galactic center, some extension along the galactic plane, and the 125 micron feature located 30 arcsec south. An asymmetry was found around Sgr A, and the variation in dust temperature across the region was calculated from the ratio of the two wavelengths. The temperature peak was around Sgr A, with subsidiary peaks associated with the 55 micron emission. A common heating source was indicated by correlations between cm wavelength sources and the temperature maps. Additionally, the distributions of NH3 and formaldehyde were also correlated with the dust distribution at the center.

Dent, W. A.↗
NASA NTRS1983

First detection of the ground-state J(K) = 1(0)-0(0) submillimeter transition of interstellar ammonia

The JK = 1 sub 0 approaching 0 sub 0 transition of ammonia at 572.5 GHz was detected in OMC-1 from NASA's Kuiper Airborne Observatory. The central velocity of the line (VLSR approximately = 9 km/s) indicates that it originates in the molecular cloud material, not the hot core. The derived filling factor of approximately 0.09 in a 2' beam implies a source diameter of approximately 35' if it is a single clump. This clump area is much larger than that derived from observations of the sub 1 inversion transition. The larger optical depth in the 1 sub 0 approaching 0 sub 0 transition (75-350) can account for the increased source area and linewidth as compared with those seen in the 1 sub 0 inversion transition. Previously announced in STAR as N83-25630

Keene, J.↗
NASA NTRS1983

Long wavelength photoconductive detectors for airborne and orbital infrared astronomy

Seven gallium doped germanium (Ge:Ga) photoconductive infrared detectors were fabricated and mounted in integrating cavities. In addition, a cold preamplifier package consisting of J230 junction field effect transistors (JFETs) was produced. Tests of the system under low photon background conditions indicated that sensitivity was limited by the Johnson noise of the load resistor. The detectors were mounted in the Ames cooled grating spectrometer, and flown on the Kuiper Airborne Observatory. Good quality astronomical data were obtained during the flight of 7 July 1983.

Houck, J. R.↗
NASA NTRS1984

A cryogenically cooled, multidetector spectrometer for infrared astronomy

A liquid helium-cooled, 24 detector grating spectrometer was developed and used for low resolution astronomical observations in the 5 to 14 micron spectral range. The instrument operated on the 91 cm Kuiper Airborne Observatory, the 3 m IRTF (Mauna Kea), the 3 m Shane telescope Observatory, the 3 m Shane telescope (Lick Observatory), and the 152 cm NASA and University of Arizona telescope. The detectors are discrete Si:Bi photoconductors with individual metal oxide semiconductor field effect transistor preamplifiers operating at 4 K. The system uses a liquid helium-cooled slit, order-sorter filter, collimator mirror, grating, and camera mirror arranged in a Czerny-Turner configuration with a cold stop added between the collimator mirror and the grating. The distances between components are chosen so that the collimator mirror images the secondary mirror of the telescope onto the cold stop, thus providing a very effective baffle. Scattered radiation is effectively reduced by using liquid helium-cooled, black baffles to divide the spectrometer into three separate compartments. The system noise-equivalent flux density, when used on the 152 cm telescope from 8 to 13 microns with a resolving power of 50, is 4.4 x 10 to the minus 17th power W/sq cm micron square root of Hz. The main applications are for measuring continuum radiation levels and solid state emission and absorption features in regions of star and planet formation.

Witteborn, F. C.↗
NASA NTRS1983

Far-infrared detection of low-luminosity star formation in the Bok globule B335

Measurements of far-infrared intensities in the Bok globule B335, made with higher spatial and spectral resolution than two earlier studies, are described. The NASA 3-m Infrared Telescope Facility was used in February 1981 and the Kuiper Airborne Observatory 0.9-m telescope was used in October 1981 and August 1982 for the observations. The far-infrared source in B335 was revealed to be more compact than previously assumed, ruling out the interstellar radiation field as the dominant heat source. The new far-infrared size, luminosity, and temperature derived suggest that these may be the first observations of low-mass star formation embedded deeply within a Bok globule. The far-infrared source does not have a near-infrared or radio continuum counterpart. High angular resolution at submillimeter wavelengths will be critical in further studies of low-mass star formation.

Davidson, J. A.↗
NASA NTRS1983

Far-infrared observations of the type 1 Seyfert galaxy NGC 4051

The Kuiper Airborne Observatory was used, together with a seven-element array, in measurements of the far-IR flux from the Seyfert galaxy NGC 4051. Flux densities within and outside of the central region were found to be comparable, with a possible local peak of emission in the west, and a total far-IR luminosity of 3.4 + or - 0.8 billion solar luminosities. The spectral shape of the radiation and its extended distribution, together with data at other wavelengths, suggest that the IR emission arises from warm dust. The relatively weak IR flux, and the apparent lack of dust and gas by comparison to the total (virial) material, indicate less active star formation than that found in such galaxies as the type 2 Seyfert, NGC 1068.

Smith, H. A.↗
NASA NTRS1982

Space Shuttle Global Positioning System (GPS) testing at NASA Johnson Space Center

The present investigation is concerned with the significance of the use of the Global Positioning System (GPS) for the Space Shuttle. On the basis of a study regarding the use of the GPS on the Space Shuttle, it was decided that such a system would greatly benefit Space Shuttle navigation. Studies with GPS user equipment were, therefore, conducted to obtain data and information which would provide a base for the formulation and the further refinement of NASA requirements with respect to the type of set the Shuttle would need. Attention is given to orbit determination, satellite numbers, background information concerning the GPS, the currently available GPS sets, the conducted studies, Shuttle sonic boom recording sites, tests performed with the aid of the Kuiper airborne observatory, and questions regarding the test applicability to Shuttle GPS.

Pawlowski, J. F.↗
NASA NTRS1984

Far-infrared and submillimeter observations of the low-luminosity protostars L1455 FIR and L1551 IRS 5 - The confinement of bipolar outflows

Far-IR observations of L1455 FIR and L1551 IRS 5 obtained in December, 1981, and in September, 1982, and January, 1983, respectively, using the H-1 and G-2 bolometer systems on the 91-cm telescope of the NASA Kuiper Aiborne Observatory are reported. Additional observations at 400 microns were obtained with UKIRT in November, 1981, (L1551) and with NASA IRTF in November, 1982 (L1455). The results are presented in tables and graphs, and L1455 and L1551 are compared with other objects in terms of central-star parameters, clouds, and overflows. The characteristics calculated for L1455 and L1551 include luminosity 1.5 and 23 solar luminosity, size less than 7 x 10 to the 16th cm, H2 density greater than or equal to 4 x 10 to the 5th and 1 x 10 to the 6th/cu cm, and 35-K dust cores of 0.2 and 0.7 solar mass, respectively. The bipolar appearance of the L1551 outflow is attributed to circumstellar material only.

Davidson, J. A.↗
NASA NTRS1983

Cooled grating infrared spectrometer for astronomical observations

A liquid helium-cooled infrared spectrometer for the 16 to 50 micron range is described. The instrument has six detectors, three each of Si:Sb and Ge:Ga and two diffraction gratings mounted back-to-back. Cold preoptics are used to match the spectrometer to the telescope. In its nominal configuration the system resolution is 0.03 micron from 16 to 30 microns and 0.07 micron from 28 to 50 microns. A cooled filter wheel is used to change order sorting filters. The gratings are driven by a steel band and gear train operating at 4 K. The detector outputs are amplified by a TIA, employing a matched pair of JFETs operating at 70 K inside the dewar. The external warm electronics include a gain stage for the TIA and dc-coupled gating circuit to remove charged-particle (cosmic-ray secondary)-induced noise spikes. The gating circuit reduces the overall system noise by a factor of two when the spectrometer is used on NASA's Kuiper Airborne Observatory. Sample spectra are presented and the deglitcher performance is illustrated.

Houck, J. R.↗
NASA NTRS1982

Airborne far-infrared and submillimeter spectroscopy

This paper is a review of airborne spectroscopic observations in the wavelength range 18-800 microns, and the instruments on the NASA Kuiper Airborne Observatory with which they were carried out. Recent measurements of spectral lines of ions, atoms and molecules are presented and discussed.

Watson, D. M.↗
NASA NTRS1984

Exploration of the Solar System by Airborne Astronomy

The contributions of airborne astronomy to the knowledge of our solar system are reviewed, beginning in 1967 when planetary observations became a vigorous part of NASA's airborne astronomy initiatives using aircraft outfitted with 30 cm diameter telescopes for infrared observations at altitudes between 12 and 15 km. These early facilities and their successor, the Kuiper airborne observatory (KAO), profoundly influenced many areas of planetary science by providing optimized platforms for the conduct of certain types of remote sensing experiments that were incompatible with both ground-based and spacecraft environments. Specific topics reviewed include energy balance in the outer planets, the composition and structure of planetary atmospheres, and planetary ring systems.

Larson, H. P.↗
NASA NTRS1984

Extreme Limb Profiles of the Sun at Far Infrared and Submillimeter Wavelengths

Limb intensity profiles at 30, 50, 100, and 200 microns, determined from Kuiper airborne observatory (KAO) observations of the occultation of the solar limb during the total eclipse of July 31, 1981, are presented. Significant but gradual limb brightening was found at the longer wavelengths consistent with the 6000 K temperature-plateau structure of the model chromospheres of Vernazza, Avrett, and Loeser. The 100 and 200 micrometers limbs are extended significantly further above the visible limb than the Vernazza, Avrett, and Loeser model predicts. These results show that the solar chromosphere is strongly perturbed from gravitational-hydrostatic equilibrium to heights as low as 1000 km. These profiles can serve as a powerful diagnostic for modeling the temperature and density of chromospheric structure free from the assumption of gravitational-hydrostatic equilibrium.

Becklin, E. E.↗
NASA NTRS1984

Measurements of H2O in Jupiter's Atmosphere from 5 Microns Airborne Observations

Measurement of the abundance and vertical distribution of H2O in Jupiter's atmosphere is discussed. Water was first detected using the Kuiper airborne observatory (KAO) and has also been observed at 5 micrometers by the Voyager infrared spectrometer, IRIS. Studies of H2O in the atmospheres of other planets require special high altitude facilities to reduce the interference of telluric H2O. Jovian H2O absorption lines are overwhelmed by terrestrial H2O at ground-based observatories but they are readily apparent in airborne spectra. Typical column abundances of H2O above ground-based telescopes are about 3000 precipitable micrometers versus only 10 pr micrometers above the KAO at the 12.5 km level. For comparison, there is about 150 pr micrometers H2O above the 3 bar level on Jupiter. Airborne observations also take advantage of cryogenic detectors which have not been used thus far on deep space probes.

Bjoraker, G. L.↗