Neon Lines Research Articles

600—Å Band of Helium

Using the third-order spectrum of a 3-m grazing incidence-type vacuum spectrograph, the 600-Å band of helium was studied in combination with an uncondensed discharge of helium operated at liquid-nitrogen temperature as well as at room temperature. The 600-Å band is tentatively explained as originating in the transition, A 1Σu+—X 1Σg+ of He2, where the A state has a potential maximum and the molecule is formed at high vibration levels of the A state by a collision of two atoms, one normal (1s2 1S0) and one metastable state (1s2s 1S0), through the potential barrier. The observed intensity enhancement of the neon line at 600.04 Å is also discussed with relation to the 600-Å band.

Wavelength Calibrations in Infrared III ν_2 of HCN at 14 Microns*

The rotational structure of the ν2 band of the HCN molecule at 14 μ has been measured using neon lines in the visible as wave-number markers and the 1–0 vibration rotation band lines of the CO molecule as secondary standards. There is good agreement between these measurements and the values calculated by Rank et al. from their observations of a number of near infrared vibration rotation bands of the HCN molecule. Some of the details of our experiences in the determination of frequencies of infrared lines have been given with a view to assist in a complete appreciation of the problems involved and the approach pursued in the solution of these problems.

Wavelength Calibrations in Infrared Part II Use of Atomic Lines from a Hollow Cathode Discharge Tube with Neon as Carrier Gas*

The possibility of using neon lines excited in a hollow cathode discharge tube for obtaining wavelength calibrations in infrared is explored. The problems involved in making use of these lines for obtaining the relative positions of the rotational lines in vibration rotation bands are discussed. The identifications of the higher order neon lines observed with a 2000-line/in. grating are made available.

Infrared spectra of noble gases (12000 to 19000 A)

The first spectra of helium, neon, argon, krypton, and xenon, excited by discharges in Geissler tubes, operated by direct connection to a transformer, have been explored in the infrared (12000 to 19000 A). A high-resolution, automatically recording, infrared spectrometer, employing a 15000-lines-per-inch grating and lead-sulfide photoconducting detector, was used as the dispersing instrument. A new set of wavelength values is reported for all these spectra. New data include 18 previously unreported lines of neon and 36 of krypton, all of which have been classified. The descriptions of the spectra of argon, krypton, and xenon represent essentially a repetition of the observations of Sittner and Peck. Several previously missing classifications are supplied, also a few amended interpretations. The analysis-of these spectra may be regarded as complete. Use of selected lines as wavelength standards is suggested..

A Recurrent Nova

ON-February 10 the variable star T Coronae Borealis, normally of magnitude 9, was seen to have blazed up to magnitude 3. This star had a typical nova outburst in 1866, when it was the first nova to be examined spectroscopically. Unlike other novae, its spectrum after fading was of late type with strong absorption bands of titanium oxide. During the last twenty years, its spectrum has varied considerably mainly through the appearance in varying strength of emission lines due to hydrogen, neutral and ionized helium, oxygen and nitrogen. In addition, forbidden lines of oxygen and neon commonly observed in nebulae have been observed.

A comparison of the atmospheres of 10 Lacertae and tau Scorpii.

Approximate line intensities measured on a Coude' plate of 10 Lacertae taken at the Mount Wilson Observatory provide data for a preliminary investigation of the atmbsphere of this star by the method of Uns&ld. From the Stark broadening of the hydrogen lines and the 10n1- zation equilibrium, the electron pressure, temperature, and surface gravity are estimated, viz., log Pe = 2.80, Te = 29,6000K, and log g = 4.44. The relative abundances of He, C, N, 0, Ne, Mg, and SI turn out to be the same as in r Sco to well within the limits of error for the approximate 10 Lacertae data. The provisional abundances expressed as relative numbers of atoms are: Element No. Atoms Element No. Atoms H 2000 0 o.8 He 130 Ne 0.7 N 0.2 Si 0.07 C 0.2 Mg 0.05 There is some suggestion that the proportion of hydrogen estimated from the Balmer discontinuity and the higher members of the Balmer series may be greater in 10 Lacertae than in r Scorpii. The discrepancy in the Ne7O ratio between the planetary nebulae and these hot stars remains; the comparable amounts of neon and oxygen in the stars recall Nova Persei which exhibited strong neon lines shortly after maximum. If the mean absorption coefficient for the stellar atmosphere is computed in the manner indicated by Chandrasekhar, Unso"ld's blanketing effect correction may be greatly reduced in size if not actually eliminated. The effective optical depths of the photosphere calculated from the central intensities of the lines and the assumption of local thermodynamic equilibrium * Of papers presented at the Seventy-fourth Meeting of the American Astronomical Society, New York, N. Y., Fehruary I and 2, 1946. on the one hand, and the amount of material above the photosphere on the other, differ by a factor of only 2.5. They differ by a factor of 20 when the Rosseland mean is used. Numerical integrations of the atmosphere, at present in progress, should decide whether any blanketing effect correction is necessary at all. Kirkwood Observatory, Indiana University, Btoomington, Ind.

The Spectrum of ν Sagittarii in the Visual Region.

view Abstract Citations (11) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Spectrum of υ Sagittarii in the Visual Region. Greenstein, Jesse L. Abstract The visual region of the spectrum of v Sgr is marked by the strength of lines of nitrogen and neon. Estimates of the abundances of the lighter elements show high abundance of neon and an abnormal abundance of nitrogen with respect to oxygen Publication: The Astrophysical Journal Pub Date: March 1943 DOI: 10.1086/144516 Bibcode: 1943ApJ....97..252G full text sources ADS |

On the Intensities of the Spectral Lines of Neon and Argon

On the Intensities of the Spectral Lines of Neon and Argon

Neon Lines in the Spectrum of υ Sagittarii

Neon Lines in the Spectrum of υ Sagittarii

THE DOPPLER EFFECT IN AN ERUPTIVE PROMINENCE

In determining the characteristics of prominence motion with the spectroheliograph the question of the possible deformation of the images by radial velocities of the internal structure is always present. This is of peculiar interest in prominences of the eruptive class. In the design of the spectroheliograph of the tower telescope at Lake Angelus we have included means whereby the chromospheric line used to make the photographs may be shifted a known amount from the second slit. This is done by observing an emission line of mercury or neon produced by a fixed slit and observed with a microscope. To test the effect of a shift on the form of a prominence the line was thus artificially displaced 1 A to the violet, then 1 A to the red on pairs of successive exposures (frames) of the motion-picture camera at intervals during the eruption. If any large radial velocities were present they would appear as changes in the prominence structure which these frames reveal.

Wave-lengths of the red lines of neon and their use as secondary standards

The spectrum of neon is dominated by a strong group of lines in the red. These are easily produced in an ordinary Geissler tube with very great intensity, and are sufficiently sharp to give measurable interference fringes with long path differences, of 120,000 waves or so. For these reasons the red lines of neon appear to be eminently suitable for use as secondary standards, and in view of the good agreement of the wave-length determinations of a number of observers (especially Burns, Meggers, and Merrill at the Bureau of Standards) they were adopted as secondary standards by the International Astronomical Union in 1922.

DURATION OF META-STABLE STATES, NEON

The rate of decay of absorption of six neon lines λ 6402, λ 6334, λ 6266, λ 6163, λ 6143 and λ 5945 has been measured for a series of pressures at room temperature and at the temperature of liquid air. Curves showing the variation of half-life with pressure have been plotted for each line at both temperatures. It is found that the function [Formula: see text] is exponential in the time, and that the rate of decay is markedly different at the same pressure and temperature for different lines ending in the same meta-stable state.

Societies and Academies

Societies and Academies

Difference in the Self-reversal of Neon Lines excited by Direct and Alternate Currents

Difference in the Self-reversal of Neon Lines excited by Direct and Alternate Currents

XI.The isotope effect in neon lines

XI.<i>The isotope effect in neon lines</i>

Electronic Fine Structure in Helium Bands

EXPERIMENTAL evidence for the triplet nature of the 2π3∏a and 2π3∏b terms of the helium molecule has recently been given by Prof. Mulliken and Dr. Monk with their grating spectrograms of the band 6400 A. (Phys. Rev., 34, 1530; 1929). The resolution into do ublets (two of the triplet components being too near to be resolved) is more clearly shown on our interference spectrogram of the same band (Fig. 1). The photograph was taken by projecting horizontal fringes formed by a 40-plate echelon (resolving power, c. 400,000) on to the fairly wide slit of a plane grating spectrograph, the latter giving a dispersion of 3.2 A. per mm. in the first order. The exposure was one hour. The neon (impurity) line 6402.246 A. served as the standard of measurements, as this line appears in two consecutive orders, their distance Δλmax being 0.64057 A.

Secondary Standards of Wave-Lenght Interferometer Measurements of Iron and Neon Lines

Secondary Standards of Wave-Lenght Interferometer Measurements of Iron and Neon Lines

Reversal of Neon Lines Examined by a Combination of a Lummer-Gehrcke Plate with a Concave Grating

Reversal of Neon Lines Examined by a Combination of a Lummer-Gehrcke Plate with a Concave Grating

Reversal of Neon Lines excited at Radiofrequency.

Reversal of Neon Lines excited at Radiofrequency.

Reversal of Neon Lines

Reversal of Neon Lines