Photoelectric photometry of bright planetary and diffuse gaseous nebulae / Электрофотометрия ярких планетарных и диффузных газовых туманностей

Razmadze, N.A. and რაზმაძე, ნ.ა. and Размадзе, Н.А. (1958) Photoelectric photometry of bright planetary and diffuse gaseous nebulae / Электрофотометрия ярких планетарных и диффузных газовых туманностей. აბასთუმნის ასტროფიზიკური ობსერვატორიის ბიულეტენი / Bulletin of the Abastumani Astrophysical Observatory (23). pp. 91-156.


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The purpose of the paper was in investigation of the planetary nebulae NGC 1535, 3242, 6210, 6543, 6572. 6720, 6826 6853 7009, 7027, 7662 and of the diffuse gaseous nebulae NGC 1976 (Orion) and 6618 (Omega), in order to determine H+, O++ and O+ concentrations in them and to evaluate the masses of luminous matter. A 33-cm reflector with a sensitive photoelectric photometer has been mainly used for the observations. In one ease the photographs of NGC 6853 were taken with Maksutov 70-cm menisK telescope. The photometer represented a combination of an antimony-cesium photoelectric multiplier and a direct current amplifier. The latter has n mounted according to Du Bridge-Brown scheme with an electrometric lamp. Fig. 8 gives a complete scheme of the photoelectric photometer. 17 Ao stars were observed to establish an absolute spectral sensitivity of the observational apparatus (photoelectric photometer and telescope). The multiplier spectral sensitivity in relative units was previously measured in the laboratory. In estimating the absolute sensitivity, the temperature for Ao stars was admitted as equal to 15000°; illuminations by the stars were based on radiometric measurements; star magnitudes were taken from the catalogues BSD and HD. Fig. 14. 15 represent the absolute spectral sensitivity of the observational equipment in deflection units/erg/sec.cm2 (illumination value). The sensitivity of the instrument is also shown in the case when light filters were used. A number of faint 7—11 magnitude stars were observed, in order to cheat the accuracy of measurements. The nebulae were being observed during 1954—1955. In treating the observations, a contribution of terrestrial^atmosphere and say background glow was taken account of Table 17 gives the definite measurement results for 11 planetary nebulae and diffuse gaseous nebula NGC 6618. Measurements for the latter were made in its bright region having 4'42" diameter. The Orion nebula was measured in its central region, in the environs of the Trapezium stars the map of which is given in fig. 16. Circles indicate the measured areas. The sizes of the former correspond to the used diaphragm with diameter of 62 angular seconds. Table 18 lists the results for the Orion nebula. The values for the relative intensities of emission lines and of the continuous spectrum of nebulae and in the case of planetary nebulae also of the cental star spectrum intensity, necessary for our calculations. were taken from other authors papers. Illuminations in the above emissions are presented in table 21 for planetary nebulae, and in table 29-for the Orion nebula. Using these data and the equations (7), (8), and (9). (§ 2) protons and twice and in some cases once ionized oxygen concentrations were calculated. Nebula masses were evaluated. Planetary nebulae distances applied in calculations were those of B. A. Vorontzov-Veliaminov. The Orion nebula distance is taken as equal to 520 ps. and that of NGC 6618—to 1100 pc. A nebula radiation absorption in the interstellar space was taken account of. The giant planetary nebula NGC 6853 was more closely investigated. Ion concentrations and mass values for several distances from the nucleus in each region were estimated. Relative data are shown in tables 25, 26 and 27. This nebula is characterized by a comparatively low density and a considerable mass. It is quite possible that the matter distribution in this nebula is influenced by the forces of electromagnetic nature. Table 30 lists the data on the Orion nebula concentrations and masses A comparison of H+, O++ concentrations in planetary nebulae and masses reveals their great variety. The NGC 7027 is characterized by a greatest density, while the NGC 6853 by a smallest one. A heavier hydrogen concentration in nebulae is associated with a heavy concentration of the twice ionized oxygen. The density of a nebula is mainly due to its volume. The mass differences of nebulae attain a centuple value. The densities of nebulae are correlated with their shapes. The very dense nebulae are planetoid-sperically shaped. The spherical double-shell nebulae have average densities. The nebulae with low density are spherically-annular. The density in the central region of the Orion nebula is rather high being of the same order as in the planetary nebulae with average density. September. 1957.

Item Type: Article
Subjects: Q Science > QB Astronomy
Divisions: Institutes > Evgeny Kharadze Abastumani National Astrophysical Observatory
Depositing User: თამარ ჭაღიაშვილი
Date Deposited: 12 Jul 2018 10:28
Last Modified: 12 Jul 2018 10:28

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