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Mount, G. H.

Publications and source records attributed to Mount, G. H..

30 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

A search for far-ultraviolet emission from Sirius B

A rocket observation of Sirius in the far-UV region from 912 to 1240 A is reported. It is found that only a few counts were detected which can possibly be attributed to the hydrogen-rich white dwarf Sirius B. An upper limit of 2.0 by 10 to the -10th power erg/sq cm per sec/A on the Sirius B flux in the range from 1000 to 1080 A is established with 99.3% confidence. This upper limit is shown to constrain the model-dependent effective temperature of Sirius B to be less than or approximately 27,000 K. It is concluded that the observed X-ray flux from Sirius cannot be emitted by the photosphere of Sirius B.

Brune, W. H.↗
NASA NTRS1978

Comprehensive analysis of gratings for ultraviolet space instrumentation

Comprehensive measurements in the vacuum UV range of 1200-3000 A of efficiency, polarization, and scattering of classically ruled and photoresist gratings are reported. The results show that the art of ruling gratings for vacuum UV use has reached a high level of sophistication and that careful analysis of grating properties can lead to useful improvement of the ruling art.

Mount, G. H.↗
NASA NTRS1978

Photoabsorption cross sections of methane and ethane, 1380-1600 A, at T equals 295 K and T equals 200 K

Photoabsorption cross sections of methane and ethane have been determined in the wavelength range from 1380 to 1600 A at room (295 K) and dry-ice (200 K) temperatures. It is found that the room-temperature ethane data are in excellent agreement with the older measurements of Okabe and Becker (1963) rather than with more recent determinations and that a small systematic blueshift occurs at the foot of the molecular absorption edges of both gases as the gases are cooled from room temperature to 200 K, a value close to the actual temperature of the Jovian atmosphere. It is concluded that methane photoabsorption will dominate until its cross section is about 0.01 that of ethane, which occurs at about 1440 A, and that ethane should be the dominant photoabsorber in the Jovian atmosphere in the region from above 1440 A to not farther than 1575 A.

Mount, G. H.↗
NASA NTRS1977

Photoabsorption cross sections of methane from 1400 to 1850 A

Photoabsorption cross sections of methane in the 1400-1850-A spectral region have been measured. Cross sections at wavelengths greater than 1475 A are approximately 200 times smaller than those currently accepted. This has a significant effect on the interpretation of spectral measurements of the Jovian planets in this wavelength region.

Mount, G. H.↗
NASA NTRS1977

Compact far ultraviolet emission source with rich spectral emission 1150-3100 A

The article describes a compact hollow Pt cathode emission source for the far UV, developed for use as a high-resolution wavelength standard in laboratory work or on spacecraft (specifically, the NASA International UV Explorer - IUE). The source is small, rugged, lightweight, spectrally rich, bright in the 1150-3200 A region, features long service life, low operating voltage, and lower power drain, and stably emits a large number of very sharp lines with a spectrum lending itself to projection onto the focal plane of a spectrograph. The source has successfully passed exacting environmental tests, and serves as a transfer standard for absolute sensitivity calibration of spectrometric instruments.

Mount, G. H.↗
NASA NTRS1975

A new solar carbon abundance based on non-LTE CN molecular spectra

A detailed non-LTE analysis of solar CN spectra strongly suggest a revised carbon abundance for the sun. We recommend a value of log carbon abundance = 8.35 plus or minus 0.15 which is significantly lower than the presently accepted value of log carbon abundance = 8.55. This revision may have important consequences in astrophysics.

Mount, G. H.↗
NASA NTRS1973

One- and multi-component models of the upper photosphere based on molecular spectra. I - The violet system of CN /0, 0/

Spectroheliograms taken in the CN (0, 0) violet band near 3883 A show very small scale network and cell structures with high contrast. The bandhead itself, which is a broad feature due to overlap of several CN lines, allows the diagnostic simplicity of a continuum since motions, magnetic fields, and broadening mechanisms are unimportant. We have obtained spectroheliograms in the bandhead and center-to-limb photoelectric spectra of CN (0, 0) at Kitt Peak National Observatory. From the photoelectric spectra and a detailed analysis of the formation of the CN (0, 0) spectrum we derive a best-fit one-component upper photospheric model differing from that of the HSRA and recommend a change in solar carbon abundance from the HSRA value.

Mount, G. H.↗