ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2019-06-28
    Description: Saturn was observed in the vicinity of the J = 10 manifold of the pure rotational band of phosphine on 1984 July 10 and 12 from NASA's Kuiper Airborne Observatory with the facility far-infrared cooled grating spectrometer. On each night observations of the full disk plus rings were made at 4 to 6 discrete wavelengths which selectively sampled the manifold and the adjacent continuum. The previously reported detection of this manifold is confirmed. After subtraction of the flux due to the rings, the data are compared with disk-averaged models of Saturn. It is found that PH3 must be strongly depleted above the thermal inversion (approx. 70 mbar). The best fitting models consistent with other observational constaints indicate that PH3 is significantly depleted at even deeper atmospheric levels ( or = 500 mbar), implying an eddy diffusion coefficient for Saturn of 10 to the 4 cm sq/sec.
    Keywords: ASTRONOMY
    Type: NASA-TM-86851 , REPT-85434 , PREPRINT-SER-042 , NAS 1.15:86851
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2019-06-28
    Description: New time-resolved H alpha, Ca II H and K and Mg II h and k spectra of the rapidly-rotating K0 dwarf star AB Doradus (= HD 36705). The transient absorption features seen in the H alpha line are also present in the Ca II and Mg II resonance lines. New techniques are developed for measuring the average strength of the line absorption along lines of sight intersecting the cloud. These techniques also give a measure of the projected cloud area. The strength of the resonance line absorption provides useful new constraints on the column densities, projected surface areas, temperatures and internal turbulent velocity dispersions of the circumstellar clouds producing the absorption features. At any given time the star appears to be surrounded by at least 6 to 10 clouds with masses in the range 2 to 6 x 10(exp 17) g. The clouds appear to have turbulent internal velocity dispersions of order 3 to 20 km/s, comparable with the random velocities of discrete filamentary structures in solar quiescent prominences. Night-to-night changes in the amount of Ca II resonance line absorption can be explained by changes in the amplitude of turbulent motions in the clouds. The corresponding changes in the total energy of the internal motions are of order 10(exp 29) erg per cloud. Changes of this magnitude could easily be activated by the frequent energetic (approximately 10(exp 34) erg) x ray flares seen on this star.
    Keywords: ASTRONOMY
    Type: NASA-CR-186563 , NAS 1.26:186563
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2006-02-14
    Description: The turn-around in the secular change in brightness of Pluto was detected, the planet is now beginning to brighten. The spectral signature was found of an ammonia bearing compound in the surface ices of Europa. Specific Io volcanic hotspots were detected from infrared photometry of the mutual events of the Jovian satellites. The polarized emission from the volcanic hotspots on Io was discovered and the locations of those hotspots were determined. The orbit of Charon was refined from speckle observations of the Pluto-Charon system. The spectral properties of liquid nitrogen-methane mixtures with reference to the infrared spectrum of Triton were studied. Major progress was made in modeling asteroid lightcurves from a modern theory of photometric properties of the asteroid surfaces. Several additional olivine-rich asteroids from near-infrared spectrophotometry were discovered. Important photometric, spectroscopic, narrow-band imaging data on Comet P/Halley was acquired, along with Schmidt photographs of Comet P/Halley and its tail.
    Keywords: ASTRONOMY
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 28-31
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2011-08-19
    Description: The design, predicted performance, and scientific objectives of the 20-30,000-MeV gamma-ray telescope EGRET for the NASA GRO spacecraft (scheduled for Space Shuttle launch to a 450-km 28.5-deg orbit in 1990) are reviewed. The other GRO instruments are briefly characterized, including the burst and transient-source experiment, the oriented scintillation spectrometer, and the imaging Compton telescope. EGRET comprises an anticoincidence system, a spark chamber, a triggering telescope, an NaI total-absorption spectrometer, a gas supply capable of refilling the chamber four times, and support electronics. EGRET will operate with energy resolution about 15 percent, effective area about 2000 sq cm, sensitivity about 5 x 10 to the -8th/sq cm sec, angular resolution 0.1-0.4 deg, and FOV about 40 deg FWHM. Observations of Galactic point sources, Galactic and extragalactic diffuse emission, gamma-ray bursts, and solar flares are planned.
    Keywords: ASTRONOMY
    Type: Space Science Reviews (ISSN 0038-6308); 49; 1-2,
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2011-08-19
    Description: VLBI observations at 2.29 GHz with fringe spacings of about 3 milliarcsec have been performed on 1398 radio sources spread over the entire sky. 917 sources were detected, including 93 percent of the identified BL Lacertae objects, 86 percent of the quasars, and 36 percent of the galaxies. The resulting catalog of compact radio sources is useful for various astrophysical studies and in the formation of VLBI celestial reference frames.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 1599-164
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2011-08-19
    Description: VLBI measurements at 2290 and 8420 MHz on baselines of 10,000 km have been used to determine the positions of the milliarcsecond nuclei in 74 extragalactic radio sources. Estimated accuracies range from 0.1 to 4.3 arcsec in both right ascension and declination with typical accuracies of about 0.3 arcsec. The observed sources are part of an all-sky VLBI catalog of milliarcsecond radio sources. Arcsecond positions have been determined for 819 sources. These positions are presently being used to identify optical counterparts in the southern hemisphere.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 590-594
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2019-07-13
    Description: IRAS sky mapping data is being reconstructed as images, and an entropy-based restoration algorithm is being applied in an attempt to improve spatial resolution in extended sources. Reconstruction requires interpolation of non-uniformly sampled data. Restoration is accomplished with an iterative algorithm which begins with an inverse filter solution and iterates on it with a weighted entropy-based spectral subtraction.
    Keywords: ASTRONOMY
    Type: Advances in image processing; Mar 31, 1987 - Apr 03, 1987; The Hague; Netherlands
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2006-02-14
    Description: The Sun-as-a-star was monitored using the McMath Fourier transform spectometer (FTS) on Kitt Peak in 1983. In 1985 the first measurement was made using the laser heterodyne technique. The FTS measurements now extend for three years, with errors of order 3 meters/sec at a given epoch. Over this 3 year period, a 33 meter/sec change was measured in the apparent velocity of integrated sunlight. The sense of the effect is that a greater blueshift is seen near solar minimum, which is consistent with expectations based on considering the changing morphology of solar granular convection. Presuming this effect is solar-cycle-related, it will mimic the Doppler reflex produced by a planetary companion of approximately two Jupiter masses, with an 11 year orbital period. Thus, Jupiter itself is below the threshold for detection by spectroscopic means, without an additional technique for discrimination. However, for planetary companions in shorter period orbits (P approx. 3 years) the threshold for unambiguous detection is well below one Jupiter mass.
    Keywords: ASTRONOMY
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 143-144
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2011-08-19
    Description: The study of the atmosphere and climate of Mars will soon be advanced considerably by the Mars Observer mission. This paper describes the atmospheric sounder for this mission and how it will measure key Martian atmospheric parameters using IR gas correlation and filter radiometry. The instrument now under development will provide high-resolution vertical profiles of atmospheric temperature, pressure, water vapor, dust, and clouds using limb sounding techniques as well as nadir observations of surface thermal properties and polar radiative balance.
    Keywords: ASTRONOMY
    Type: Applied Optics (ISSN 0003-6935); 25; 4232-424
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2011-08-19
    Description: Plasma analyzer data obtained by Pioneer 7 during its approach to about 12.1 million km from the nucleus of Comet P/Halley are presently interpreted as He(+) generated by charge exchange of the solar wind He(2+) with neutral cometary material. The maximum He(+) flux was detected several hours after the closest March 20, 1986 approach of the spacecraft, and is noted to be not only larger than expected, but also to exhibit large, discontinuous flux changes.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 71; 192-197
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...