YY Geminorum: A Very Late Type Close Binary with Possible Magnetic Stellar Wind

2002 ◽  
Vol 124 (2) ◽  
pp. 1060-1063 ◽  
Author(s):  
Shengbang Qian ◽  
Dengliang Liu ◽  
Wenli Tan ◽  
Boonrucksar Soonthornthum
Keyword(s):  
Stellar Wind ◽  
Close Binary ◽  
Late Type

Alfv�n wave-driving mechanism of late-type stellar wind

1990 ◽  
Vol 167 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Young Zheng ◽  
Li Xiao-Qing
Keyword(s):  
Stellar Wind ◽  
Driving Mechanism ◽  
Late Type ◽  
N Wave

Analysis of 11 Late-Type Close Binary Systems

1984 ◽  
pp. 411-411
Author(s):  
K. C. Leung ◽  
D. S. Zhai ◽  
R. X. Zhang ◽  
Q. Y. Liu ◽  
J. T. Zhang ◽  
...  
Keyword(s):  
Binary Systems ◽  
Close Binary ◽  
Late Type ◽  
Close Binary Systems

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).

scholarly journals THE CHROMOSPHERIC ACTIVITY OF [HH97] FS Aur-79: A CLOSE BINARY WITH LATE-TYPE ACTIVE (dK7e+dM3e) COMPONENTS

2011 ◽  
Vol 141 (4) ◽  
pp. 124 ◽  
Author(s):  
S. J. Austin ◽  
J. W. Robertson ◽  
T. R. de Souza ◽  
C. Tycner ◽  
R. K. Honeycutt
Keyword(s):  
Close Binary ◽  
Late Type ◽  
Chromospheric Activity

Analysis of 11 late-type close binary systems

1984 ◽  
Vol 99 (1-2) ◽  
pp. 411-411
Author(s):  
K. C. Leung ◽  
D. S. Zhai ◽  
R. X. Zhang ◽  
Q. Y. Liu ◽  
J. T. Zhang ◽  
...  
Keyword(s):  
Binary Systems ◽  
Close Binary ◽  
Late Type ◽  
Close Binary Systems

scholarly journals Lithium Depletion in Late-Type Stars Through Wind-Driven Mixing

1995 ◽  
Vol 10 ◽  
pp. 461-462 ◽  
Author(s):  
J.-P. Zahn
Keyword(s):  
Binary Stars ◽  
Causal Link ◽  
Close Binary ◽  
Late Type ◽  
Lithium Abundance ◽  
Convective Envelope ◽  
Halo Stars ◽  
Close Binary Stars ◽  
Nuclear Burning ◽  
Lithium Depletion

A well established property of late-type stars is that their rotation rate and their lithium abundance both decline with age. We understand why such stars are spun down while losing so little mass (Schatzman 1962), but we are still working on a theory which would explain all aspects of the observed lithium depletion. Although most agree that some kind of mixing must occur below the convective envelope of late-type stars, which transports 7Li to the depth where it is destroyed through nuclear burning, the physical process which is responsible for this transport is still in debate. However the most recent observations of the lithium abundance in close binary stars clearly show that there is a causal link between the destruction of lithium and the loss of angular momentum: consistently, tidally-locked binaries tend to display more lithium than single stars of the same effective temperature, as observed in the Hyades (Soderblom et al. 1990, Thorburn et al. 1993) and among old disk stars and halo stars (Spite et al. 1994).

scholarly journals Analysis of 11 Late-Type Close Binary Systems

1984 ◽  
Vol 80 ◽  
pp. 411-411
Author(s):  
K. C. Lfung ◽  
D. S. Zhai ◽  
R. X. Zhang ◽  
Q. Y. Liu ◽  
J. T. Zhang ◽  
...  
Keyword(s):  
United States ◽  
Preliminary Report ◽  
Binary Systems ◽  
Computational Analysis ◽  
The United States ◽  
Close Binary ◽  
Late Type ◽  
Joint Research ◽  
Joint Research Project ◽  
University Of Nebraska Lincoln

AbstractThis is a preliminary report on the joint research project between 3 observatories: Beijing, Yunnan, and Behlen Observatories from China and the United States. The systems we have been dealing with are primary of late spectral types and with short periods. Most.of the observations were secured from the observatories in China. The computational analysis is carried out in University of Nebraska, Lincoln. The photometric solutions are based on the Wilson and Devinney method. Out of 11 systems analyzed 6 of them: AO Cam. ER Ori. BX Peg, BB Peg, U Peg, and SW Lac are found to be contact systems. All of them are having their primary eclipses at occultation. Therefore they can be classified as W-type WUMa systems. They also show other W-type characteristics.

scholarly journals Radio and X-Ray Emissions from Chemically Peculiar B- and A-Type Stars: Observations and a Model

1993 ◽  
Vol 138 ◽  
pp. 507-516 ◽  
Author(s):  
Jeffrey L. Linsky
Keyword(s):  
Energy Source ◽  
Stellar Wind ◽  
Mechanical Energy ◽  
Early Type ◽  
Late Type ◽  
X Ray ◽  
Nonthermal Radio ◽  
Chemically Peculiar ◽  
Early Type Stars

AbstractConventional wisdom holds that early-type and late-type stars have very different outer atmospheres, because the early-type stars lack deep convective zones. I argue that the magnetic chemically peculiar (CP) stars hotter than about spectral type A2 display many of the activity phenomena seen in the most active late-type stars. In particular, many CP stars are luminous nonthermal radio and coronal x-ray sources like the RS CVn systems. A wind-fed magnetosphere model has been proposed to explain both the nonthermal radio and the x-ray emission. In this model the stellar wind plays the role of a mechanical energy source analogous to the role played by convection in the active late-type stars.

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