О смещениях абсорбционных линий в спектре P Cygni / On the Displacements of Absorption Lines in the Spectrum of P Cygni

Kharadze, E.K. and ხარაძე, ე.კ. and Харадзе, Е.К. (1937) О смещениях абсорбционных линий в спектре P Cygni / On the Displacements of Absorption Lines in the Spectrum of P Cygni. აბასთუმნის ასტროფიზიკური ობსერვატორიის ბიულეტენი / Bulletin of the Abastumani Astrophysical Observatory (1). pp. 39-46.


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From the point of view of the problem of P Cygni, the investigation of its radial velocities is of an extremely great interest. Such investigation led O. Struve to two important results: 1) of two lines of a given intensity, the one of lower ionization potential has a greater velocity and 2) for any given element the strong lines exhibit a greater velocity than the faint ones. The correlations given by O. Struve are extremely remarkable and they could have thrown much light on the problem of P Cygni if a certain circumstance had not obliged us to regard them critically. As a matter of fact all previous studies of displacements overlooked the question of the influence of neighbouring bright emission on the contour and the displacement of dark component. As a result of this influence, the reality of values of radial velocities and of the difference of displacements of lines may be exposed to doubts. The author investigated the photographic effect by studying special plates of P Cygni's spectrum having different intensities of emission lines. These investigations, as well as some experiments reproducing in laboratory conditions the artificial continuous spectra crossed by paired lines with bright and dark components, similar to what takes place in P Cygni's spectrum, enabled us to establish the presence of the effect and to perform the quantitative estimation of this effect. We grouped the spectrogramms in a special manner, so that each group could be characterized by the mean value of in¬tensity (I) of a chosen emission line and the mean value of displacement (D) or the radial velocity of corresponding absorption component and, finally, we drew a reduction curve (I. D), from which we could derive the corrections to radial velocity of absorption lines, i. e. reduce the velocities to one and the same value of intensity of emission components. This considerably reduced the errors in the values of radial velocities of absorption lines. The velocities thus corrected for all the lines that we measured in the spectrum of P Cygni (in the spectral region λ 3750 - λ 6600 ) are given in Table I. Using the obtained data we examined the correlation between radial velocities and ionization potentials. As a result we obviously have ground to consider the existence of this correlation (V, I. P.) as absolutely real (Fig. 1). On the other band, it is seen from Table II, in which the velocities are arranged in the order of the increase of line intensities, that the correlation bet¬ween the velocities and intensities does not exist or, at least, its effect is extremely Small. The results of our investigation of the correlation (V, I (em) /I(obs)) on the basis of the data of Table I, summed up in Table III, are expressed by curves (V, I (em) /I(obs)) and (I. P.,I (em)/I(obs)) represented in Fig. 2 and 3. May, 1936

Item Type: Article
Subjects: Q Science > QB Astronomy
Divisions: Institutes > Evgeny Kharadze Abastumani National Astrophysical Observatory
Depositing User: თამარ ჭაღიაშვილი
Date Deposited: 18 May 2018 11:39
Last Modified: 02 Jun 2018 18:15
URI: http://eprints.iliauni.edu.ge/id/eprint/7973

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