Emission-line Stars and Early-type Stars with Gaia

2010 ◽  
Vol 45 ◽  
pp. 373-376 ◽  
Author(s):  
R. Blomme ◽  
Y. Frémat ◽  
A. Lobel ◽  
C. Martayan
Keyword(s):  
Emission Line ◽  
Early Type ◽  
Early Type Stars

scholarly journals X-Ray Emission-Line Profiles of Three Early-Type Stars Observed with Chandra

2007 ◽  
Vol 59 (1) ◽  
pp. 237-244 ◽  
Author(s):  
Norimasa Yamamoto ◽  
Haruko Takano ◽  
Shunji Kitamoto ◽  
Takayoshi Kohmura
Keyword(s):  
Emission Line ◽  
Line Profiles ◽  
Early Type ◽  
X Ray ◽  
Early Type Stars

scholarly journals Emission-Line Stars as Interacting Binaries (Review Paper)

1987 ◽  
Vol 92 ◽  
pp. 339-360 ◽  
Author(s):  
P. Harmanec
Keyword(s):  
Emission Line ◽  
Review Paper ◽  
Early Type ◽  
Theoretical Concepts ◽  
Early Type Stars ◽  
Observational Techniques ◽  
Binary Hypothesis

A general binary hypothesis of the emission-line phenomenon in early-type stars was published eleven years ago (Kříž & Harmanec 1975, Harmanec & Kříž 1976; for a reformulation see Harmanec 1982). Since then, new observational techniques and theoretical concepts have led to a number of exciting findings which have made the emission-line phenomenon even more puzzling and challenging than before. It is therefore of interest to ask whether the binary hypothesis can withstand all these developments or not.

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.

scholarly journals Chemical Abundances of Early Type Stars

1998 ◽  
Vol 188 ◽  
pp. 224-225
Author(s):  
S. Tanaka ◽  
S. Kitamoto ◽  
T. Suzuki ◽  
K. Torii ◽  
M.F. Corcoran ◽  
...  
Keyword(s):  
Surface Layer ◽  
Stellar Wind ◽  
Nuclear Reactions ◽  
X Rays ◽  
Early Type ◽  
Chemical Abundances ◽  
X Ray ◽  
Low Metallicity ◽  
Early Type Stars

X-rays from early-type stars are emitted by the corona or the stellar wind. The materials in the surface layer of early-type stars are not contaminated by nuclear reactions in the stellar inside. Therefore, abundance study of the early-type stars provides us an information of the abundances of the original gas. However, the X-ray observations indicate low-metallicity, which is about 0.3 times of cosmic abundances. This fact raises the problem on the cosmic abundances.

scholarly journals UV Spectral Classification of B Stars

1985 ◽  
Vol 111 ◽  
pp. 411-413
Author(s):  
Janet Rountree ◽  
George Sonneborn ◽  
Robert J. Panek
Keyword(s):  
Classification System ◽  
Classification Criteria ◽  
High Dispersion ◽  
Spectral Classification ◽  
Early Type ◽  
B Stars ◽  
Dimensional Classification ◽  
Early Type Stars ◽  
Comprehensive Classification

Previous studies of ultraviolet spectral classification have been insufficient to establish a comprehensive classification system for ultraviolet spectra of early-type stars because of inadequate spectral resolution. We have initiated a new study of ultraviolet spectral classification of B stars using high-dispersion IUE archival data. High-dispersion SWP spectra of MK standards and other B stars are retrieved from the IUE archives and numerically degraded to a uniform resolution of 0.25 or 0.50 Å. The spectra (in the form of plots or photowrites) are then visually examined with the aim of setting up a two-dimensional classification matrix. We follow the method used to create the MK classification system for visual spectra. The purpose of this work is to examine the applicability of the MK system (and in particular, the set of standard stars) in the ultraviolet, and to establish classification criteria in this spectral region.

scholarly journals The Use of Model Atmospheres for Temperature-Gravity Calibration

1973 ◽  
Vol 54 ◽  
pp. 173-221
Author(s):  
J. C. Pecker
Keyword(s):  
Model Building ◽  
Stellar Atmosphere ◽  
Line Formation ◽  
Early Type ◽  
New Concepts ◽  
Total Luminosity ◽  
Classical Models ◽  
Early Type Stars ◽  
Two Parameters

Regardless of the degree of elaboration of series of models, just how can they be used for calibration purposes? And how much is this calibration sensitive to the quality of the model theory? These two questions are the basis of our discussion, which covers : I – The general principles of the use of model atmospheres in stellar calibration (1 – The two dimensional classifications; 2 – The use of the total luminosity; 3 – The cases of Vega and Sirius; 4 – The calibration of ST – Teff relation); II – The failures of the two parameters model atmospheres (1 – The observational need for more-than-two-parameters classification; 2 – The abundance of elements, the line formation, and the model atmospheres; 3 – Various sources of unadequacy of models; 4 – Envelopes or shell features; their influence on model-building; 5 – The case of HD 45677. Diagnostic of early-type stars; 6 – Various unexplained spectral features); III – The present state of the model factory (1 – The classical models; 2 – New concepts in the description of a stellar atmosphere; 3 – New approaches in model making; 4 – Conclusions).

Massive early-type emission-line stars: an attempt to distinguish a new group of stellar objects

1995 ◽  
Vol 224 (1-2) ◽  
pp. 519-520 ◽  
Author(s):  
A. S. Miroshnichenko ◽  
Yu. K. Bergner ◽  
D. B. Mukanov ◽  
T. A. Shejkina
Keyword(s):  
Emission Line ◽  
Early Type ◽  
Stellar Objects

X‐Ray Emission from Early‐Type Stars in the Orion Nebula Cluster

2005 ◽  
Vol 160 (2) ◽  
pp. 557-581 ◽  
Author(s):  
B. Stelzer ◽  
E. Flaccomio ◽  
T. Montmerle ◽  
G. Micela ◽  
S. Sciortino ◽  
...  
Keyword(s):  
Orion Nebula ◽  
Early Type ◽  
X Ray ◽  
Early Type Stars
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