A catalog of pre-main-sequence emission-line stars with IRAS source associations

1990 ◽  
Vol 74 ◽  
pp. 575 ◽  
Author(s):  
David A. Weintraub
Keyword(s):  
Emission Line ◽  
Main Sequence ◽  
Iras Source

scholarly journals Radiative-transfer modelling of funnel flows

2007 ◽  
Vol 3 (S243) ◽  
pp. 83-94
Author(s):  
Tim J. Harries
Keyword(s):  
Numerical Methods ◽  
Radiative Transfer ◽  
Emission Line ◽  
Main Sequence ◽  
Line Profiles ◽  
Stellar Radius ◽  
Transfer Modelling ◽  
Synthetic Line ◽  
Made In ◽  
Geometry And Kinematics

AbstractEmission line profiles from pre-main-sequence objects accreting via magnetically-controlled funnel flows encode information on the geometry and kinematics of the material on stellar radius scales. In order to extract this information it is necessary to perform radiative-transfer modelling of the gas to produce synthetic line profiles. In this review I discuss the physics that needs to be included in such models, and the numerical methods and assumptions that are used to render the problem tractable. I review the progress made in the field over the last decade, and summarize the main successes and failures of the modelling work.

scholarly journals Photometry of AM Her Stars – Line and Continuum Emission

1979 ◽  
Vol 53 ◽  
pp. 324-328
Author(s):  
Paula Szkody
Keyword(s):  
Emission Line ◽  
White Dwarf ◽  
Main Sequence ◽  
Close Binary ◽  
Line Spectrum ◽  
Continuum Emission ◽  
Late Type ◽  
Emission Line Spectrum ◽  
Orbital Periods

The 4 known AM Her stars or polars (AM Her, ANUMa, W Pup, and 2A0311-227) are characterized by large circular polarizations of 10-35%, (Tapia 1977a, b, Krzeminski and Serkowski 1977), an emission line spectrum with strong H and He lines (Crampton and Cowley 1977, Greenstein et al. 1977), complex photometric variations (Szkody 1978, Priedhorsky and Krzeminski 1978, Warner & Nather 1972), long term high and low states and short orbital periods (80-180 min.). Models of these systems envision a close binary containing a magnetic white dwarf primary (B ~ 108G) and late type main sequence secondary transferring material into an accretion funnel over one or both poles of the white dwarf (Stockman et al. 1977, Lamb & Masters 1979, Liebert et al. 1978).

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.

scholarly journals Be Star Surveys in Open Clusters with Balmer-line Photometry

2000 ◽  
Vol 175 ◽  
pp. 63-66
Author(s):  
Gemma Capilla ◽  
Juan Fabregat ◽  
Deborah Baines
Keyword(s):  
Emission Line ◽  
Main Sequence ◽  
Open Clusters ◽  
Balmer Line ◽  
Be Stars ◽  
Late Type ◽  
Efficient Tool ◽  
Be Star ◽  
Almost All ◽  
Evolutionary Interpretation

AbstractWe present CCD Hα and Hβ photometry of young open clusters. We show that the comparison of the α and β photometric indices provides an efficient tool for identifying emission line stars. We report on the discovery of several new Be stars.The preliminary results of our survey are the following: i. the younger clusters (age < 10 Myr) are almost lacking of Be stars, ii. clusters in the age interval 10–30 Myr are rich in Be stars. Almost all of them are of spectral types earlier than B5, while late-type Be stars are scarce. These results point towards an evolutionary interpretation of the Be phenomenon, in the sense that Be stars are close to the end of their main sequence lifetime.

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 Triggered massive star formation in the open cluster NGC 1893

2003 ◽  
Vol 212 ◽  
pp. 562-563
Author(s):  
Amparo Marco ◽  
Ignacio Negueruela
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Massive Star ◽  
Main Sequence ◽  
Open Cluster ◽  
Star Forming ◽  
Young Open Cluster ◽  
H Ii Region ◽  
Pms Stars ◽  
Bright Emission

We have carried out a search for emission line pre-main sequence (PMS) stars in the area of the star-forming young open cluster NGC 1893 by means of slitless spectroscopy. We find 19 emission line stars with spectral types spanning the range from early B-type to G-type. All the PMS stars are confined to two small regions: the outer rim of the molecular cloud associated with the H ii region IC 410 and the vicinity of the bright emission cometary nebulae Sim 129 and Sim 130. The overall spatial distribution of PMS stars strongly suggests, that present day star formation in NGC 1893 is triggered by the O-type stars in the cluster.

Photoionization models with accretion discs

1988 ◽  
Vol 103 ◽  
pp. 119-121
Author(s):  
M. Vogel
Keyword(s):  
Emission Line ◽  
White Dwarf ◽  
Main Sequence ◽  
Flux Distribution ◽  
Small Region ◽  
Accretion Disc ◽  
Accretion Discs ◽  
Strong Emission

AbstractThe diagnositic possibilities for identifying the ionizing source in symbiotic systems are explored. As possible sources we consider hot blackbodies and accretion discs. It turns out that main sequence accretors and hot blackbodies may have the same appearance in both, emission line and continuum flux distribution. However, UV continuum indices of models containing an accretion disc around a white dwarf are confined to a very small region, separated from main sequence accretors and blackbodies. Furthermore, if symbiotic systems containing a white dwarf accretor exist, they might be recognizable by strong emission in Fe X λ6374.

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.

Sign in / Sign up

Export Citation Format

Share Document