Results 221 to 230 of about 285,532 (266)
Some of the next articles are maybe not open access.
2001
The title of this chapter presupposes that there exists a Sun that is Non-active or Quiet. Modern research, however, is discovering more and more that there is no such thing as a perfectly placid Sun. Activity occurs on all scales at all times in the solar atmosphere.
David Alexander, Loren W. Acton
openaire +1 more source
The title of this chapter presupposes that there exists a Sun that is Non-active or Quiet. Modern research, however, is discovering more and more that there is no such thing as a perfectly placid Sun. Activity occurs on all scales at all times in the solar atmosphere.
David Alexander, Loren W. Acton
openaire +1 more source
Rotations of the sun and stars and their activity
Kinematics and Physics of Celestial Bodies, 2009An equation for determining the magnetic activity cycle for the lower main-sequence stars is derived on the basis of the results of an analysis of magnetic structure drift with the solar activity cycle. The equation correlates the star activity cycle with the period of its rotation Trot, the B−V color index, and the average chromospheric emission level
O. S. Gopasyuk, S. I. Gopasyuk
openaire +1 more source
2020
The Sun is the star closest to us and the only star where details can be directly observed. By comparison of the parameters describing the Sun with other stars, we understand the physics of stars in more detail and by comparing e.g. our present Sun with stars that are younger or older than the Sun, we can learn about the evolution of the Sun, its ...
openaire +1 more source
The Sun is the star closest to us and the only star where details can be directly observed. By comparison of the parameters describing the Sun with other stars, we understand the physics of stars in more detail and by comparing e.g. our present Sun with stars that are younger or older than the Sun, we can learn about the evolution of the Sun, its ...
openaire +1 more source
Solar Physics, 1979
Macrospicules have been observed in Hα and He i D3, on the disk and above the limb. In 1975, a rate of 1400 (A⊙day)−1 is inferred, and the ratio of equatorial to polar rates ≲ 2. D3 intensities are a few × 10−3 of the disk center, and do not decrease in coronal holes. The ratio of Hα to D3 intensities is ≈ 10.
openaire +1 more source
Macrospicules have been observed in Hα and He i D3, on the disk and above the limb. In 1975, a rate of 1400 (A⊙day)−1 is inferred, and the ratio of equatorial to polar rates ≲ 2. D3 intensities are a few × 10−3 of the disk center, and do not decrease in coronal holes. The ratio of Hα to D3 intensities is ≈ 10.
openaire +1 more source
On the Localization of Sun-Spot and Floccular Activity on the Sun's Surface
Publications of the Astronomical Society of the Pacific, 1935In an investigation of the influence of the relative positions of Venus and the Earth upon sun-spots, ten successive series of 584 days each were used and the mean spottedness of the Sun for each day of one synodic revolution of Venus was determined. It was then noticed that there were frequent recurrences of maximum and minimum sun-spot activity at ...
openaire +1 more source
2003
The Sun’s magnetic field and differential rotation give rise to much complexity in its structure and activity over a large range in both spatial and temporal scales. The most notable among these is the solar activity cycle of 11 years, or magnetic cycle of 22 years.
openaire +1 more source
The Sun’s magnetic field and differential rotation give rise to much complexity in its structure and activity over a large range in both spatial and temporal scales. The most notable among these is the solar activity cycle of 11 years, or magnetic cycle of 22 years.
openaire +1 more source
The Physician and Sportsmedicine, 2000
Damage from long-term, cumulative effects of sun exposure, while slow to develop, can become life-threatening. The cutaneous effects of ultraviolet light include sunburn, photosensitivity, immunosuppression, premature aging, and several types of skin cancer.
openaire +2 more sources
Damage from long-term, cumulative effects of sun exposure, while slow to develop, can become life-threatening. The cutaneous effects of ultraviolet light include sunburn, photosensitivity, immunosuppression, premature aging, and several types of skin cancer.
openaire +2 more sources
The nature of the active regions of the sun
Vistas in Astronomy, 1965Abstract The appearance of active regions of the Sun is associated with a 10 to 20 per cent increase in convection velocity. This increase is due to the fact that a weak magnetic field in the active regions suppresses small-scale motions and decreases turbulent viscosity. A more intensive flux of wave energy results in a greater density of the corona
openaire +1 more source
Development of active regions on the Sun
Journal of Physical Studies, 2021O. A. Baran +4 more
openaire +1 more source