Results 291 to 300 of about 130,683 (338)
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Annual Review of Astronomy and Astrophysics, 1985
The variety of stellar chromospheric and coronal activity provides a framework for understanding solar and stellar magnetic activity. It is pointed out that the recognition of an 11-yr periodicity within the record of sunspot numbers is a relatively recent discovery of just over a century ago.
Sallie L. Baliunas, Arthur H. Vaughan
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The variety of stellar chromospheric and coronal activity provides a framework for understanding solar and stellar magnetic activity. It is pointed out that the recognition of an 11-yr periodicity within the record of sunspot numbers is a relatively recent discovery of just over a century ago.
Sallie L. Baliunas, Arthur H. Vaughan
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Astrophysics and Space Science, 1972
The relation between the average magnetic fieldB, the angular velocity Ω, and the periodP of stellar activity cycles is studied. For the calculations we have used Leighton's (1969) model for the solar cycle with the additional assumption that the differential rotation and the cyclonic turbulence (Parker, 1955) (that is the ‘sunspot tilt’ or the ‘α ...
B. R. Durney, J. O. Stenflo
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The relation between the average magnetic fieldB, the angular velocity Ω, and the periodP of stellar activity cycles is studied. For the calculations we have used Leighton's (1969) model for the solar cycle with the additional assumption that the differential rotation and the cyclonic turbulence (Parker, 1955) (that is the ‘sunspot tilt’ or the ‘α ...
B. R. Durney, J. O. Stenflo
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Advances in Space Research, 2000
Abstract I review recent results on coronal activity in late-type stars stressing the similarities and differences with respect to solar coronal activity. The emphasis is on recent stellar observations by ROSAT, ASCA and SAX and on prospects for future observations by AXAF and XMM.
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Abstract I review recent results on coronal activity in late-type stars stressing the similarities and differences with respect to solar coronal activity. The emphasis is on recent stellar observations by ROSAT, ASCA and SAX and on prospects for future observations by AXAF and XMM.
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Changing stellar activity cycles
Astronomische Nachrichten, 2007AbstractWe investigated continuous long‐term photometric datasets of thirteen active stars, Ca II variability of one single mainsequence star, and 10.7 cm radio data of the Sun, with simple Fourier‐ and time‐frequency analysis. The data reflect the strength of the activity manifested in magnetic spots. All studied stars show multiple (2 to 4) cycles of
K. Oláh +4 more
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Inferences on Stellar Activity and Stellar Cycles from Asteroseismology
Space Science Reviews, 2014The solar activity cycle can be studied using many different types of observations, such as counting sunspots, measuring emission in the Ca II H&K lines, magnetograms, radio emissions, etc. One of the more recent ways of studying solar activity is to use the changing properties of solar oscillations.
William J. Chaplin, Sarbani Basu
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Astrophysics and Space Science, 1998
This review is limited to solar-type stars (late-F to early-K main sequence stars) and to recent developments in the study of the evolution of angular momentum in those stars. Observations of rotation in young clusters are discussed, together with the models that have been put forth to account for what is seen.
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This review is limited to solar-type stars (late-F to early-K main sequence stars) and to recent developments in the study of the evolution of angular momentum in those stars. Observations of rotation in young clusters are discussed, together with the models that have been put forth to account for what is seen.
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Stellar analogs of solar magnetic activity
Solar Physics, 1985The techniques and principal results of observational studies of stellar activity are summarized. Both chromospheric and coronal emission clearly track surface magnetic field properties, but it is not well known how the detailed relation between the emission and surface magnetic fields varies with spectral type.
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The Solar-stellar Connection: Magnetic Braking and Stellar Activity
Publications of the Astronomical Society of Australia, 1992AbstractThe theory of coronal structure and of the associated angular momentum transport by magneto-thermo-centrifugal winds is reviewed, with reference to recent observations of rapidly rotating late-type stars. In particular, the combined optical and X-ray studies of AB Doradus are consistent with the predicted picture of a hot, magnetically ...
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Solar and Stellar Magnetic Activity
2000This timely volume provides the first comprehensive review and synthesis of current understanding of magnetic fields in the Sun and similar stars. Magnetic activity results in a wealth of phenomena - including starspots, non-radiatively heated outer atmospheres, activity cycles, deceleration of rotation rates, and even, in close binaries, stellar ...
C. J. Schrijver, C. Zwaan
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1987
The most important signatures and parameters of stellar magnetic activity and their relation with global stellar parameters are briefly reviewed with the aim of indicating which are the most significant data that are required to constrain possible models of stellar activity. The sporadic and cyclic variability aspect is, particularly stressed, firstly,
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The most important signatures and parameters of stellar magnetic activity and their relation with global stellar parameters are briefly reviewed with the aim of indicating which are the most significant data that are required to constrain possible models of stellar activity. The sporadic and cyclic variability aspect is, particularly stressed, firstly,
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