Results from Three Dimensional Spectral Classification of Population II Stars Using the DDO Photometric System

1973 ◽  
pp. 176-182 ◽  
Author(s):  
W. Osborn
Keyword(s):  
Three Dimensional ◽  
Photometric System ◽  
Spectral Classification

scholarly journals Photometric Classification of Stars in the Vilnius Observatory

1973 ◽  
Vol 50 ◽  
pp. 183-185 ◽  
Author(s):  
V. Straižys
Keyword(s):  
Spatial Distribution ◽  
Chemical Composition ◽  
Stellar Evolution ◽  
Three Dimensional ◽  
Point Of View ◽  
Photometric System ◽  
Intermediate Band ◽  
Dimensional Classification

The programs of three-dimensional classification of stars using eight-color intermediate band photometric system are described. They include (1) investigation of interstellar reddening and absorption in the direction of objects significant from point of view of stellar evolution, (2) investigation of spatial distribution of stars of different spectral classes, luminosities and chemical composition, (3) the detection of unique objects.

scholarly journals Results from Three Dimensional Spectral Classification of Population II Stars Using the DDO Photometric System

1973 ◽  
Vol 50 ◽  
pp. 176-182
Author(s):  
W. Osborn
Keyword(s):  
Globular Clusters ◽  
Three Dimensional ◽  
Photometric System ◽  
Horizontal Branch ◽  
Intermediate Band ◽  
Theoretical Predictions ◽  
The Mean ◽  
Red Giant ◽  
The Masses

The David Dunlap Observatory (DDO) intermediate-band photometric system described in the previous paper has been used to observe a number of red giant branch, horizontal branch, and asymptotic branch members in each of the five globular clusters M3, M5, M10, M13, and M92. A calibration of the DDO system is described by which it was possible to determine the effective temperatures, surface gravities, [Fe/H] values, and masses of the observed stars. The mean [Fe/H] values for the clusters were found to be −1.01 for M3, −0.68 for M5, −1.44 for M10, −1.69 for M13, and −1.96 for M92. Evidence was found that the masses of the horizontal branch and asymptotic branch stars are systematically smaller than those of red giant branch members. Two stars were discovered to have CN bands that are anomalously strong for Population II objects. The observational results have been compared with the theoretical predictions of two detailed Population II evolutionary tracks and in general the agreement is good.

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.

scholarly journals Three‐dimensional Spectral Classification of Low‐Metallicity Stars Using Artificial Neural Networks

2001 ◽  
Vol 562 (1) ◽  
pp. 528-548 ◽  
Author(s):  
Shawn Snider ◽  
Carlos Allende Prieto ◽  
Ted von Hippel ◽  
Timothy C. Beers ◽  
Christopher Sneden ◽  
...  
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Three Dimensional ◽  
Spectral Classification ◽  
Low Metallicity ◽  
Artificial Neural

scholarly journals Analysis of 30 Wolf-Rayet Stars

1988 ◽  
Vol 108 ◽  
pp. 141-142
Author(s):  
W. Schmutz ◽  
W.-R. Hamann ◽  
U. Wessolowski
Keyword(s):  
Mass Loss ◽  
Three Dimensional ◽  
Spectral Classification ◽  
Radio Flux ◽  
Ionization Equilibrium ◽  
Model Calculations ◽  
Visual Magnitude ◽  
The Individual ◽  
Loss Rates

Temperatures, mass-loss rates and luminosities of 30 galactic Wolf-Rayet stars (24 WN, 6 WC) are derived by fitting the observed equivalent widths of He I λ5876 and He II λ5412 and the absolute visual magnitude. A three-dimensional grid (T*-R*-) of model calculations provides the theoretical values.The results are summarized in Figure 1. The different symbols denote the spectral classification of the individual stars, whereas four groups are distinguished: WNEA, WNE-B, WNL and WC stars. The size of the symbols indicates the mass-loss rates. The uncertainties of the results are estimated to be 0.1 dex in T*, 0.4 dex in and 0.5 dex in L. For the ll stars in common with the sample of Abbott et al. (1986) we find our mass-loss rates to be compatible with their radio flux if the correct ionization equilibrium in the radio emitting region is applied (Schmutz and Hamann, 1986). The model calculations show that for all but the WN2 and WN3 stars helium recombines to He+ before the ions enter the radio-emitting region.

scholarly journals Spectral Classification of Early Type Stars from the Low Dispersion Ultraviolet Spectra

1977 ◽  
Vol 4 (2) ◽  
pp. 289-301 ◽  
Author(s):  
K. Nandy
Keyword(s):  
Spectral Type ◽  
Main Sequence ◽  
Photometric System ◽  
Spectral Classification ◽  
Early Type ◽  
Ultraviolet Spectra ◽  
Early Type Stars ◽  
Natural Groups ◽  
Low Dispersion

The methods of spectral classification from the low dispersion ultraviolet spectra obtained with the S2/68 experiment in the TD1 satellite have been described. The bright stars, the spectra of which are photometrically accurate, can be divided into natural groups according to the spectral appearance of the features. These features vary in strength with spectral type and luminosity, and enable separation between main sequence and luminous stars. The limits for these stars areat BO toat AO. For fainter stars the spectral data have been combined to obtain narrow band magnitudes at several wavelengths. These photometric bands have an effective width of 100 A. An ultraviolet photometric system which enables determinations of spectral type and luminosity of early type stars is described and the results for about 3000 stars is presented. The photometric system considered here consists of the ultraviolet colour indices (m2740−V,) (m2190−V) and (m1490−V).

Note on the spectral classification of carbon stars in the photographic infrared region

1966 ◽  
Vol 24 ◽  
pp. 21-23
Author(s):  
Y. Fujita
Keyword(s):  
Infrared Region ◽  
Spectral Classification ◽  
Carbon Stars

We have investigated the spectrograms (dispersion: 8Å/mm) in the photographic infrared region fromλ7500 toλ9000 of some carbon stars obtained by the coudé spectrograph of the 74-inch reflector attached to the Okayama Astrophysical Observatory. The names of the stars investigated are listed in Table 1.

Phonetic iconicity in the evaluative morphology of a sample of Indo-European, Niger-Congo and Austronesian languages

2010 ◽  
Vol 3 (2) ◽  
pp. 156-180 ◽  
Author(s):  
Renáta Gregová ◽  
Lívia Körtvélyessy ◽  
Július Zimmermann
Keyword(s):  
Three Dimensional ◽  
Sound Symbolism ◽  
Three Dimensional Model ◽  
Austronesian Languages ◽  
Place Of Articulation ◽  
European Languages ◽  
Phonetic Symbolism ◽  
The Individual ◽  
Core Vocabulary

Universals Archive (Universal #1926) indicates a universal tendency for sound symbolism in reference to the expression of diminutives and augmentatives. The research ( Štekauer et al. 2009 ) carried out on European languages has not proved the tendency at all. Therefore, our research was extended to cover three language families – Indo-European, Niger-Congo and Austronesian. A three-step analysis examining different aspects of phonetic symbolism was carried out on a core vocabulary of 35 lexical items. A research sample was selected out of 60 languages. The evaluative markers were analyzed according to both phonetic classification of vowels and consonants and Ultan's and Niewenhuis' conclusions on the dominance of palatal and post-alveolar consonants in diminutive markers. Finally, the data obtained in our sample languages was evaluated by means of a three-dimensional model illustrating the place of articulation of the individual segments.

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