Space Distribution and State of Motion of the Early-Type Stars, Open Clusters, Associations and Stellar Rings

1971 ◽  
pp. 85-109 ◽  
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Open Clusters ◽  
Space Distribution ◽  
Early Type ◽  
Early Type Stars

scholarly journals Delta Scuti Stars in Open Clusters: w2 and w20 in NGC 2264 and h501 and h906 in α Per

2000 ◽  
Vol 176 ◽  
pp. 465-466
Author(s):  
J. H. Peña ◽  
R. Peniche ◽  
F. Cervantes ◽  
R. M. García ◽  
J. P. Sareyan
Keyword(s):  
Chemical Composition ◽  
Effective Temperature ◽  
Variable Stars ◽  
Open Clusters ◽  
Early Type ◽  
Early Type Stars ◽  
Delta Scuti ◽  
Scuti Stars ◽  
Δ Scuti Stars

There are many advantages to studying variable stars in open clusters; the parameters that determine the evolution of the stars, such as chemical composition and age, can be considered to be the same for all the stars in the cluster. These data, along with the mass, effective temperature and superficial gravity, allow us to better determine the physics which explain the pulsation mechanisms. In the present paper the variable stars h501 and h906 in α Per and w2 and w20 in NGC 2264 are studied. In particular, the reasons why δ Scuti stars coexist with early type stars in NGC 2264 is examined.

scholarly journals The Occurrence of Abnormal Stars in Open Clusters

1979 ◽  
Vol 47 ◽  
pp. 95-98 ◽  
Author(s):  
Helmut A. Abt
Keyword(s):  
Open Clusters ◽  
Line Profiles ◽  
Early Type ◽  
Hydrogen Line ◽  
Early Type Stars

AbstractMorgan, Keenan, and others have found that low dispersions (80-130 Å mm-1) are ideal for obtaining spectral types and luminosity classes, especially for early-type stars. This is because at those dispersions certain blends are unresolved and remain useful, the hydrogen line wings are seen most clearly, and differences in rotational velocities are not so important. Such dispersions are also ideal or adequate for detecting some peculiarities, such as Am and Be spectra and some extreme Ap spectra, but they are inadequate for detecting abnormalities involving weak lines (as in Ap(Hg, Mn) stars) and line profiles (such as in shell spectra).

scholarly journals Photometric investigation of the association Car OB 2

1970 ◽  
Vol 38 ◽  
pp. 265-269
Author(s):  
W. Seggewiss
Keyword(s):  
Luminosity Function ◽  
Main Sequence ◽  
Open Clusters ◽  
Early Type ◽  
Standard Sequence ◽  
Luminosity Functions ◽  
Color Excess ◽  
Photometric Investigation ◽  
Early Type Stars

A photometric investigation of the association Car OB 2 was carried out with a photoelectric standard sequence observed with the ESO photometric telescope and plates taken with the ADH telescope of Boyden Observatory. The distance of Car OB 2 is 2.04 kpc, the color excess EB–V is 0m.38. The main sequence of this ‘OB’ association reaches at least to late A-type stars. The luminosity function was determined and compared with the luminosity functions of very young open clusters observed by Walker (1957). The distance of a group of 13 early-type stars in the area of Car OB 2 (‘group c’) was found to be 2.5 kpc, the reddening 0m.68. The relation of Car OB 2 and group c to the structure of the Carina arm is regarded.

scholarly journals Photometry of early type stars in open clusters (NGC 1444, NGC 1662, NGC 2129, NGC 2169 and NGC 7209)

1994 ◽  
Vol 162 ◽  
pp. 303-304
Author(s):  
J. H. Peña ◽  
R. Peniche
Keyword(s):  
Open Clusters ◽  
Early Type ◽  
Number Of Clusters ◽  
Pulsating Stars ◽  
Blue Stragglers ◽  
Chemical Enrichment ◽  
Short Period ◽  
The Galaxy ◽  
Early Type Stars ◽  
Delta Scuti

This is part of a series which has the purpose of examining the nature of the stars belonging to open clusters. The aim of this series is, among others things, to study short period pulsating stars, mainly of the Delta Scuti type, by first establishing the membership of each star to the cluster, to determine the abundance of the Be and Ap phenomena and blue stragglers in open clusters for clusters of different ages and metalicities and, eventually, to study the chemical enrichment of the galaxy when age, dynamics and metalicity are known for a fair number of clusters.

Condensation of paper on the “Revision of the Calibration of Absolute magnitudes by Hγ absorption”

1966 ◽  
Vol 24 ◽  
pp. 304-310
Author(s):  
R. M. Petrie
Keyword(s):  
Absolute Magnitude ◽  
Open Clusters ◽  
Distance Scale ◽  
Early Type ◽  
B Stars ◽  
Measured Absorption ◽  
Early Type Stars ◽  
Absolute Magnitudes ◽  
Photometric Distance

1. The relation between the measured absorption at Hγand absolute magnitude was made for A stars (B8–A3) in 1950 and for B stars in 1953. The systems so obtained gave lower luminosities than the MK calibration and the more recently derived photometric-distance scale. Furthermore, the rise of photo-electric three-colour photometry has recently made available accurate magnitudes and colour excesses of a substantial number of early-type stars in the nearer open clusters. A reconsideration of the Hγ–Mrelation then appeared to be feasible and worth while.

Some results of the Barbier-Chalonge-Divan system of stellar classification

1966 ◽  
Vol 24 ◽  
pp. 77-90 ◽  
Author(s):  
D. Chalonge
Keyword(s):  
Early Type ◽  
Parameter System ◽  
Early Type Stars ◽  
Two Parameter

Several years ago a three-parameter system of stellar classification has been proposed (1, 2), for the early-type stars (O-G): it was an improvement on the two-parameter system described by Barbier and Chalonge (3).

Radio Continuum Measurements of Southern Early‐Type Stars. III. Nonthermal Emission from Wolf‐Rayet Stars

1999 ◽  
Vol 518 (2) ◽  
pp. 890-900 ◽  
Author(s):  
Jessica M. Chapman ◽  
Claus Leitherer ◽  
Barbel Koribalski ◽  
Roderick Bouter ◽  
Michelle Storey
Keyword(s):  
Radio Continuum ◽  
Early Type ◽  
Nonthermal Emission ◽  
Early Type Stars

Preliminary Observations of Interstellar Sodium D-Line Absorption towards the Carina Nebula

1980 ◽  
Vol 4 (1) ◽  
pp. 95-97 ◽  
Author(s):  
J. B. Whiteoak ◽  
F. F. Gardner
Keyword(s):  
High Resolution ◽  
Hii Regions ◽  
Early Type ◽  
Interstellar Clouds ◽  
Carina Nebula ◽  
Line Absorption ◽  
General Investigation ◽  
Early Type Stars ◽  
Resolution Study

As part of a general investigation of interstellar clouds associated with southern HII regions we have begun a high-resolution study of the sodium D-line absorption in the directions of early-type stars that are likely to be associated with or located behind the clouds.

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