Ultraviolet spectroscopy
Ultraviolet spectroscopic measurements on Mars upper atmosphere by Mariners 6 and 7
Anderson, G. P.↗
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Ultraviolet spectroscopy of planetary atmospheres
Ultraviolet spectroscopy of planetary atmospheres
PLANETARY ATMOSPHERE↗
Future Directions in Ultraviolet Spectroscopy
The 'Future Directions in Ultraviolet Spectroscopy' conference was inspired by the accomplishments of the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission. The FUSE mission was launched in June 1999 and spent over eight years exploring the far-ultraviolet universe, gathering over 64 million seconds of high-resolution spectral data on nearly 3000 astronomical targets. The goal of this conference was not only to celebrate the accomplishments of FUSE, but to look toward the future and understand the major scientific drivers for the ultraviolet capabilities of the next generation fo space observatories. Invited speakers presented discussions based on measurements made by FUSE and other ultraviolet instruments, assessed their connection with measurements made with other techniques and, where appropriate, discussed the implications of low-z measurements for high-z phenomena. In addition to the oral presentations, many participants presented poster papers. The breadth of these presentation made it clear that much good science is still in progress with FUSE data and that these result will continue to have relevance in many scientific areas.
Sonneborn, George↗
ULTRAVIOLET SPECTROSCOPY OF PLANETARY ATMOSPHERES
Ultraviolet spectroscopic investigation of dayglow and aurora in planetary atmospheres
PLANETARY ATMOSPHERE↗
Ultraviolet spectroscopy of meteoric debris of comets
It is proposed to carry out slitless spectroscopy at ultraviolet wavelengths from orbit of meteoric debris associated with comets. The Eta Aquarid and Orionid/Halley and the Perseid/1962 862 Swift-Tuttle showers would be principal targets. Low light level, ultraviolet video technique will be used during night side of the orbit in a wide field, earthward viewing mode. Data will be stored in compact video cassette recorders. The experiment may be configured as a GAS package or in the HITCHHIKER mode. The latter would allow flexible pointing capability beyond that offered by shuttle orientation of the GAS package, and doubling of the data record. The 1100 to 3200 A spectral region should show emissions of atomic, ionic, and molecular species of interest on cometary and solar system studies.
Wdowiak, T. J.↗
Ultraviolet spectroscopy of meteoric debris: In situ calibration experiments from Earth orbit
It is proposed to carry out slitless spectroscopy at ultraviolet wavelengths from orbit of meteoric debris associated with comets. The Eta Aquarid, Orionid/Halley, and the Persied/1962 862 Swift-Tuttle showers would be principal targets. Low light level, ultraviolet video technique will be used during night side of the orbit in a wide field, earthward viewing mode. Data will be stored in compact video cassette recorders. The experiment may be configured as a GAS package or in the HITCHHIKER mode. The latter would allow flexible pointing capability beyond that offered by shuttle orientation of the GAS package, and doubling of the data record. The 1100 to 3200 A spectral region should show emissions of atomic, ionic, and molecular species of interest on cometary and solar system studies.
Nuth, J. A., III↗
Ultraviolet spectroscopy of meteoric debris: In situ calibration experiments from earth orbit
It is proposed to carry out slitless spectroscopy at ultraviolet wavelengths from orbit of meteoric debris associated with comets. The Eta Aquarid, Orionid/Halley, and the Persied/1962 862 Swift-Tuttle showers would be principal targets. Low light level, ultraviolet video technique will be used during the night side of the orbit in a wide field, earthward viewing mode. Data will be stored in compact video cassette recorders. The experiment may be configured as a GAS package or in the HITCHHIKER mode. The latter would allow flexible pointing capability beyond that offered by shuttle orientation of the GAS package, and doubling of the data record. The 1100 to 3200 A spectral region should show emissions of atomic, ionic, and molecular species of interest on cometary and solar system studies.
Nuth, Joseph A.↗
Non-Destructive Evaluation of Materials via Ultraviolet Spectroscopy
A document discusses the use of ultraviolet spectroscopy and imaging for the non-destructive evaluation of the degree of cure, aging, and other properties of resin-based composite materials. This method can be used in air, and is portable for field use. This method operates in reflectance, absorbance, and luminescence modes. The ultraviolet source is used to illuminate a composite surface of interest. In reflectance mode, the reflected response is acquired via the imaging system or via the spectrometer. The spectra are analyzed for organic compounds (conjugated organics) and inorganic compounds (semiconducting band-edge states; luminescing defect states such as silicates, used as adhesives for composite aerospace applications; and metal oxides commonly used as thermal coating paints on a wide range of spacecraft). The spectra are compared with a database for variation in conjugation, substitution, or length of molecule (in the case of organics) or band edge position (in the case of inorganics). This approach is useful in the understanding of material quality. It lacks the precision in defining the exact chemical structure that is found in other materials analysis techniques, but it is advantageous over methods such as nuclear magnetic resonance, infrared spectroscopy, and chromatography in that it can be used in the field to assess significant changes in chemical structure that may be linked to concerns associated with weaknesses or variations in structural integrity, without disassembly of or destruction to the structure of interest.
Pugel, Betsy↗
Ultraviolet spectroscopy of planets
Spectroscopy of planetary ultraviolet radiation - Rayleigh scattering and electron excitation
ELECTRON INTERACTION↗
Ultraviolet spectroscopy of comets using sounding rockets, IUE and Spacelab
Ultraviolet spectroscopy is a very powerful tool for the study of cometary atmospheres since the four elemental cosmic species, H, C, N and O, as well as several simple molecules made from these species, have their strong resonance transitions in the ultraviolet region of the spectrum. However, due to the opacity of the atmosphere to ultraviolet, these observations must be made from space. Results are presented for observations of sevral comets along with plans for further cometary spectroscopy.
Feldman, P. D.↗
Ultraviolet spectroscopy of the brightest supergiants in M31 and M33
Ultraviolet spectroscopy from the IUE, in combination with groundbased visual and infrared photometry, are to determine the energy distributions of the luminous blue variables, the Hubble-Sandage variables, in M31 and M33. The observed energy distributions, especially in the ultraviolet, show that these stars are suffering interstellar reddening. When corrected for interstellar extinction, the integrated energy distributions yield the total luminosities and black body temperatures of the stars. The resulting bolometric magnitudes and temperatures confirm that these peculiar stars are indeed very luminous, hot stars. They occupy the same regions of the sub B01 vs. log T sub e diagram as do eta Car, P Cyg and S Dor in our galaxy and the LMC. Many of the Hubble-Sandage variables have excess infrared radiation which is attributed to free-free emission from their extended atmospheres. Rough mass loss estimates from the infrared excess yield rates of 0.00001 M sub annual/yr. The ultraviolet spectra of the H-S variables are also compared with similar spectra of eta Car, P Cyg and S For.
Humphreys, R. M.↗
Optical and ultraviolet spectroscopy of three F + B binary stars
Optical and ultraviolet spectroscopy is presented for three F + B objects that are members of the first group of strongly interacting, F II + B systems. The data obtained confirm that HD 59771, HD 242257, and CoD -30 5135 are all binary star systems consisting of a luminous F-type component and a B star. Strong, variable H-alpha emission is seen in all the stars. It is found that the UV spectrum of HD 59771 resembles the spectrum of HD 207739. CoD -30 5135 has the most dramatic mid-UV spectrum seen among the scores of observed cool + hot star systems.
Bopp, Bernard W.↗
Ultraviolet spectroscopy of Venus - Initial results from the Pioneer Venus orbiter
Ultraviolet spectroscopy of the Venus cloud tops reveals absorption features attributed to sulfur dioxide in the atmosphere above the cloud tops. Measurements of scattered sunlight at 2663 angstroms show evidence for horizontal and vertical inhomogeneities in cloud structure. Images of the planet at SO2 absorption wavelengths show albedo features similar to those seen at 3650 angstroms from Mariner 10. Airglow emissions are consistent with an exospheric temperature of about 275 K, and a night airglow emission has been detected, indicating the precipitation of energy into the dark thermosphere.
Stewart, A. I.↗
Ultraviolet spectroscopy of comets
Results of observations of comets in the ultraviolet are reviewed in relation to their significance for the chemistry and physics of the cometary coma and the composition of the cometary ice. Ultraviolet cometary observations began in 1970, when a hydrogen envelope was discovered extending millions of kilometers from the nucleus of comet Bennett, and continued with the discovery of oxygen and carbon in comet Kohoutek and the acquisition of comprehensive UV spectra from comets West (1976 VI), Seargent (1978 XV) and Bradfield (1979 X). The available cometary spectra are remarkably similar, indicative of a common composition and origin for comets and the insignificance of chemical reactions in the inner coma to species abundances. Ultraviolet spectroscopy has also allowed the determination of gas production rates from either the surface brightness or the total luminosity in a given spectral line. IUE observations of comet Bradfield reveal the water production rate to vary as the -3.7 power of heliocentric distance from 0.71 to 1.55 AU, incompatible with solar energy input as the controlling influence on water vaporization.
Feldman, P. D.↗
Ultraviolet spectroscopy of the outer layers of stars
Recent results of the ultraviolet spectroscopy of the outer layers of stars are reviewed both for early-type stars and for cool stars; the discussion is limited to extended atmospheres and circumstellar envelopes, for which fundamental advantages are offered by ultraviolet observations. Some important observational work still needed is outlined, and several useful observations possible with instruments that are compatible with the Spacelab format are described.
Snow, T. P., Jr.↗
Ultraviolet spectroscopy of comae
Vacuum ultraviolet observations from sounding rockets and satellite observatories of the gaseous comae of several recent comets are reviewed. The earliest of these led to discovery of the hydrogen envelope extending for millions of km from the nucleus. Subsequent observations of H I Lyman alpha, the OH (0,0) band and the oxygen resonance triplet have provided strong evidence for the water-ice model of the cometary nucleus. Several new species were discovered in the coma, including C, C(+), CO, S and CS. High-resolution spectroscopy and the spatial variation of the observed emissions provide means to elucidate the production and excitation mechanisms of these species. The similarity of the spectra of the half-dozen comets observed to date argues for a common, homogeneous composition (with the exception of dust and CO) of the cometary ice and a minimal effect on the neutral species due to molecular collisions in the inner coma.
Feldman, P. D.↗
Ultraviolet spectroscopy of cometary comae - An update
This report provides an update to the reviews of ultraviolet spectroscopy of comets presented by Feldman (1982, 1983). Recent developments are largely related to the use of the International Ultraviolet Explorer (IUE), which to date has now observed approximately 20 comets. Distant, dusty comets are considered, taking into account Comet Bowell (1982 I), and Comet Cernis (1983l). Attention is also given to earth-approaching comets, the periodic Comet Encke in 1980 and 1984, and planned ultraviolet observations of P/Halley. It is pointed out that a large number of ultraviolet spectroscopic and imaging programs are planned for the 1985-86 apparition of Comet Halley utilizing encounter spacecraft, satellite and Space Shuttle borne observatories, and suborbital sounding rocket flights.
Feldman, P. D.↗
Determination of nuclear charge radius by extreme-ultraviolet spectroscopy of Na-like ions
We report on a method for determining the absolute nuclear charge radius of high-𝑍 elements using extreme-ultraviolet spectroscopy of highly charged Na-like ions in tandem with highly accurate atomic structure calculations of transition energy differences. The application of this method has reduced the nuclear charge radius uncertainty of 191 Ir by a factor of 8 from the currently accepted literature value, with a recently reported charge radius of 5.435(12) fm. The result reduces the charge radius uncertainty along the full Ir isotopic chain when combined with prior optical isotope shift measurements. The technique utilizes only a few million ions stored in an ion trap, which should apply to measurements with small quantities of radioactive nuclei.
Atom & ion trapping & guiding↗