A search for weak H-alpha emission line pre-main-sequence stars

1983 ◽  
Vol 88 ◽  
pp. 431 ◽  
Author(s):  
E. D. Feigelson ◽  
G. A. Kriss
Keyword(s):  
Emission Line ◽  
Main Sequence ◽  
Main Sequence Stars ◽  
Alpha Emission

Stellar rotation in lower main-sequence stars measured from time variations in H and K emission-line fluxes. I - Initial results

1981 ◽  
Vol 250 ◽  
pp. 276 ◽  
Author(s):  
A. H. Vaughan ◽  
G. W. Preston ◽  
S. L. Baliunas ◽  
L. W. Hartmann ◽  
R. W. Noyes ◽  
...  
Keyword(s):  
Emission Line ◽  
Main Sequence ◽  
Stellar Rotation ◽  
Main Sequence Stars ◽  
Time Variations ◽  
Initial Results

Absolute Fluxes of K Chromospheric Emission on the H-R Diagram

1976 ◽  
Vol 71 ◽  
pp. 473-473
Author(s):  
C. Blanco ◽  
S. Catalano ◽  
E. Marilli
Keyword(s):  
Emission Line ◽  
Main Sequence ◽  
Previous Analysis ◽  
Main Sequence Stars ◽  
Chromospheric Emission

Continuing our previous analysis of the chromospheric emission (Blanco et al., 1974), absolute fluxes of the K emission line have been evaluated from 10 Å mm−1 spectrograms of the O. C. Wilson collection for 31 F5-K7 main sequence stars and 172 G2-M5 giants.

Stellar rotation in lower main-sequence stars measured from time variations in H and K emission-line fluxes. II - Detailed analysis of the 1980 observing season data

1983 ◽  
Vol 275 ◽  
pp. 752 ◽  
Author(s):  
S. L. Baliunas ◽  
L. Hartmann ◽  
R. W. Noyes ◽  
H. Vaughan ◽  
G. W. Preston ◽  
...  
Keyword(s):  
Emission Line ◽  
Detailed Analysis ◽  
Main Sequence ◽  
Stellar Rotation ◽  
Main Sequence Stars ◽  
Time Variations

scholarly journals Emission line spectropolarimetry and circumstellar structures

2014 ◽  
Vol 10 (S305) ◽  
pp. 288-292
Author(s):  
Jorick S. Vink
Keyword(s):  
Emission Line ◽  
Accretion Disks ◽  
Main Sequence ◽  
Gamma Ray ◽  
Young Stars ◽  
Main Sequence Stars ◽  
Current Sensitivity ◽  
Luminous Blue Variables ◽  
3D Monte Carlo

AbstractWe discuss the role of linear emission-line polarimetry in a wide set of stellar environments, involving the accretion disks around young pre-main sequence stars, to the aspherical outflows from O stars, luminous blue variables and Wolf-Rayet stars, just prior to explosion as a supernova or a gamma-ray burst. We predict subtle QU line signatures, such as single/double QU loops for un/disrupted disks. Whilst there is plenty of evidence for single QU loops, suggesting the presence of disrupted disks around young stars, current sensitivity (with S/N of order 1000) is typically not sufficient to allow for quantitative 3D Monte Carlo modeling. However, the detection of our predicted signatures is expected to become feasible with the massive improvement in sensitivity of extremely large mirrors.

scholarly journals H$_{\bf\alpha}$ emission in pre-main sequence stars. I. An atlas of line profiles

1996 ◽  
Vol 120 (2) ◽  
pp. 229-256 ◽  
Author(s):  
Bo Reipurth ◽  
A. Pedrosa ◽  
M. T.V.T. Lago
Keyword(s):  
Main Sequence ◽  
Line Profiles ◽  
Main Sequence Stars ◽  
Alpha Emission

scholarly journals A Survey of Northern Bok Globules and the Mon OB1/RI Association For H-Alpha Emission Stars

1984 ◽  
Vol 78 ◽  
pp. 283-286
Author(s):  
Katsuo Ogura ◽  
Tatsuhiko Hasegawa
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Direct Approach ◽  
Main Sequence Stars ◽  
Radio Observations ◽  
Alpha Emission ◽  
Gum Nebula ◽  
Bok Globules ◽  
Emission Stars ◽  
Relationship Of

The most direct approach to the suggested relationship of Bok globules to star formation is to search for actual spots of star birth in or around them. But no protostellar objects have hitherto been found by infrared and/or radio observations. Optically relevant to this are the discoveries of some Herbig-Haro objects and pre-main sequence stars associated with cometary globules inside the Gum Nebula (Reipurth 1983).

scholarly journals Optical and H-Alpha Emission from Unresolved Red Dwarf Stars in the Galaxy

1990 ◽  
Vol 139 ◽  
pp. 107-109
Author(s):  
G. Szécsényi-Nagy
Keyword(s):  
Main Sequence ◽  
Stellar Content ◽  
Main Sequence Stars ◽  
M Dwarfs ◽  
Dwarf Stars ◽  
Alpha Emission ◽  
Cool Stars ◽  
Red Dwarfs ◽  
The Galaxy ◽  
Red Dwarf Stars

Although many of the nearest dim and cool stars (the red dwarfs) were catalogued in the early sixties, the majority of the astronomers did not realize that these objects provide almost nine tenths of all the stars in our Galaxy. In fact 90-95% of the stars in the solar vicinity (r ≤ 25 pc) are main sequence stars, and at least 80% of them are M dwarfs. Outside the main sequence (MS) one can find a few subdwarfs and somewhat more white dwarfs, but the contribution of this latter type is not known precisely. Estimates range between 4% and 8%. The relative frequency of giants and supergiants can not be determined from the census of the local star population because they are not represented in a statistically meaningful number. But investigations of much greater cosmic volumes demonstrate that luminosity classes Ia, Ib, II, III, and IV altogether contribute fewer than 1% of the stellar content of the Galaxy.

scholarly journals On the origin of the correlations between the accretion luminosity and emission line luminosities in pre-main-sequence stars

2015 ◽  
Vol 452 (3) ◽  
pp. 2837-2844 ◽  
Author(s):  
I. Mendigutía ◽  
R. D. Oudmaijer ◽  
E. Rigliaco ◽  
J. R. Fairlamb ◽  
N. Calvet ◽  
...  
Keyword(s):  
Emission Line ◽  
Main Sequence ◽  
Main Sequence Stars

Emission-Line Pre-Main-Sequence Stars and X-Ray Sources in Orion

1995 ◽  
Vol 447 ◽  
pp. 342 ◽  
Author(s):  
Steven H. Pravdo ◽  
Lorella Angelini
Keyword(s):  
Emission Line ◽  
Main Sequence ◽  
Main Sequence Stars ◽  
X Ray

scholarly journals A survey of line profile variations in non-emission line B0–B5 III–V stars

1994 ◽  
Vol 162 ◽  
pp. 108-109
Author(s):  
M. S. Fieldus ◽  
C. T. Bolton
Keyword(s):  
Spectral Line ◽  
Emission Line ◽  
Line Profile ◽  
Main Sequence ◽  
Line Of Sight ◽  
Main Sequence Stars ◽  
B Stars ◽  
Preliminary Results ◽  
Spectral Line Profile ◽  
Nonradial Pulsation

Some investigators have attributed the photometric and spectral line profile variations (lpv) that are common among the B stars to nonradial pulsation while others have attempted to explain them by rotation of photospheric or circumstellar structures with respect to our line of sight. One of the problems in resolving this debate has been our lack of knowledge of how these variations depend on fundamental stellar characteristics. Surveys of lpv have covered the Be and a few Bn stars (D. Penrod, unpublished), the O stars (Fullerton 1990), and B8-B9.5 main sequence stars (Baade 1989), but noone has carried out a systematic search for lpv among the near main sequence, non-emission line early- and mid-B stars. This paper describes preliminary results from such a survey.

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