scholarly journals Some Physical Parameters and UVBY β Photometry of Trapezium Type Multiple Systems

1995 ◽  
Vol 166 ◽  
pp. 391-391
Author(s):  
G.N. Salukvadze ◽  
G. Sh. Javakhishvili
Keyword(s):  
Photon Counting ◽  
Physical Parameters ◽  
Photometric System ◽  
Early Type ◽  
Multiple Systems ◽  
Early Type Stars ◽  
Absolute Magnitudes ◽  
Bolometric Correction ◽  
Semi Empirical ◽  
Mirror Telescope

The presented paper deals with the results of electrophotometric observations of 59 components of 19 trapezia in Strömgren and Crawford six-colour photometric system. The multiple systems, selected from the Abastumani Catalogue of Trapezia (Salukvadze, 1978), are: ABAO 2, 8, 34, 48, 51, 62, 75, 94, 245, 312, 313, 316, 324, 348, 356, 363, 387, 396.Observations were made on the 125-cm mirror telescope with the use of a one-channel photometer, based on photon counting, with diaphragms 10″ and 20″. Reduction was done on the Observatory computer with a procedure described by Salukvadze and Javakhishvili (1989).We calculated the indices [m1],[c1] and [u-b] as in (Strömgren 1967, Philip and Egret 1980). The unreddened indices (b-y), m1 and c1 were calculated by the formulae of Crawford (1975).Semi-empirical calibrations for effective temperature, bolometric correction and mass for early-type stars, using Strömgren photometric indices c0 and beta, are given by Balona (1984). In order to determine absolute magnitudes we used the calibration from Balona and Shobbrook (1984).

scholarly journals A Preliminary Test of the Calibration of the Hβ System in Terms of Absolute Magnitudes and Intrinsic Colours for Early-Type Stars

1973 ◽  
Vol 54 ◽  
pp. 114-116
Author(s):  
A. F. J. Moffat ◽  
Th Schmidt-Kaler ◽  
N. Vogt
Keyword(s):  
Main Sequence ◽  
Preliminary Test ◽  
Physical Parameters ◽  
Early Type ◽  
B Stars ◽  
Early Type Stars ◽  
Absolute Magnitudes

The dependency of the Hβ-index on two physical parameters is briefly discussed. The previous calibration of Mv(β) (Fernie, 1965 or Crawford, 1971) is confirmed for main sequence O and B stars; however, the β-values of the later B-supergiants tend to be too large for their absolute magnitudes. The problem of filtering out stars with marginal emission is emphasized.

scholarly journals The Zero-Point of the Cepheid Luminosity Scale from a Calibration of the Luminosities of Early-Type Stars

1985 ◽  
Vol 82 ◽  
pp. 201-202
Author(s):  
L. A. Balona ◽  
R. R. Shobbrook
Keyword(s):  
Zero Point ◽  
Photometric System ◽  
Early Type ◽  
Early Type Stars ◽  
The Absolute ◽  
Absolute Magnitudes ◽  
Zero Points

AbstractA new calibration of the absolute magnitudes of early-type stars in terms of the (β, c0) photometric system is used to establish the distance moduli of clusters containing Cepheids. The zero points of the period – luminosity and period – luminosity – colour relations are calculated and compared to previous determinations.

scholarly journals Classification of Early Type Stars on the Dominion Astrophysical Observatory Photometric System

1973 ◽  
Vol 50 ◽  
pp. 152-161
Author(s):  
S. C. Morris ◽  
G. Hill ◽  
G. A. H. Walker ◽  
H. I. B. Thompson
Keyword(s):  
Classification Method ◽  
Photometric System ◽  
Early Type ◽  
Balmer Series ◽  
Early Type Stars ◽  
Independent Parameters

A classification method has been developed for early–type stars observed on the Dominion Astrophysical Observatory photometric system. Two reddening-independent parameters, Q(35) and Q(38), are used. Q(35) is a measure of the Balmer discontinuity, while Q(38) is a measure of the strength of the upper members of the Balmer series. A preliminary calibration of Q(35) and Q(38) in terms of spectral types and luminosity classes is given, and applications to several groups of stars are shown.

scholarly journals Some Physical Parameters and uv by β Photometry of Trapezium Type Multiple Systems

1995 ◽  
Vol 164 ◽  
pp. 378-378
Author(s):  
G.N. Salukvadze ◽  
G.Sh. Javakhishvili
Keyword(s):  
Physical Parameters ◽  
Photometric System ◽  
Multiple Systems ◽  
Trapezium Type

The present paper deals with the results of electrophotometric observations of 59 components of 19 trapezia in the Stroemgren and Crawford six-colour photometric system.

scholarly journals The hydrogen lines as luminosity criteria in early-type stars

1964 ◽  
Vol 20 ◽  
pp. 71-76
Author(s):  
J. A. Graham
Keyword(s):  
Calibration Procedure ◽  
Galactic Structure ◽  
Short Paper ◽  
Early Type ◽  
Early Type Stars ◽  
The Absolute ◽  
Absolute Magnitudes ◽  
Hydrogen Lines

In this short paper, the calibration procedure for the absolute magnitudes derived from the Hβ indices will be discussed. These Hβ indices have been measured for the distant OB-type stars in our studies of galactic structure and are discussed in the paper by Bok which is found elsewhere in this volume (Paper 36).

scholarly journals The Estimation of the Electron Density ne with a Narrow-Band Photometric System Calibrated by Model Atmospheres

1985 ◽  
Vol 111 ◽  
pp. 557-560
Author(s):  
M. Gerbaldi ◽  
N. Morguleff
Keyword(s):  
Electron Density ◽  
Narrow Band ◽  
Photometric System ◽  
Early Type ◽  
Peculiar Stars ◽  
Early Type Stars ◽  
Definition Of

A spectrophotometer was originally designed by Barbier (1960) for the study of early-type stars. The band passes were chosen to measure the features of the hydrogen spectrum. To the first definition of the system (Barbier and Morguleff 1964), two more bands were added, specifically devoted to the peculiar stars of type Ap and Am (Gerbaldi 1972). The interpretation of these observations has already been given separately. We will concentrate here on the calibration of this spectrophotometric system in terms of Teff, log g and electron density ne.

scholarly journals Two Dimensional Spectral Classification of Early Type Stars by Narrow Band Photometry

1979 ◽  
Vol 47 ◽  
pp. 507-518
Author(s):  
M. Gerbaldi ◽  
N. Morguleff
Keyword(s):  
Narrow Band ◽  
Statistical Technique ◽  
Photometric System ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Early Type ◽  
Early Type Stars ◽  
Independent Parameters ◽  
Best Parameters

AbstractSpectrophotometry data of 775 early type stars in a narrow band photometric system are analyzed, looking for the best parameters for a two dimensional spectral classification in the spectral region 3575 Å - 6000 Å. A correlation is established with the MK classification. The statistical technique of Principal Componant Analysis is applied to determine the number of linearly independent parameters among the data.

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