About this Research Topic
Observations have revealed that the Sun and the stars possess the common magnetic activity and eruptive phenomena in their atmosphere. The observational approaches include light curve and spectrum for both the Sun and the stars as well as spatial resolution imaging, mostly for the Sun. The wavelength bands include the white light for photosphere, optical spectral lines for chromosphere, ultraviolet for chromosphere and transition region, and soft X-ray for corona. The radio observations also provide information on solar and stellar magnetic activity. The magnetic features in the photosphere, such as the spots and faculae, cause rotational modulation in the observed solar and stellar light curves. The optical spectral lines such as Ca II H&K and Hα can indicate chromospheric activities. Measurements of the stellar magnetic field demonstrate a relatively stronger global magnetic field of stars than that of the Sun. Long-term observations disclose the solar and stellar activity cycles. The stellar activities indicated by the X-ray intensities observed via space satellites show a clear relationship between the activity level and the rotation rate of stars, which gives strong implications on the magnetic dynamo process in the convection zones of stars. Like the helioseismology technique for the Sun, the asteroseismology approach can give clues of stellar internal structures as well as the activities manifested on the surface of the stars.
The flare activity is a prominent eruptive phenomenon found on both the Sun and the stars. The solar mass ejections in chromosphere and corona are commonly observed on the Sun, and modern observations also provide evidence of chromospheric and coronal mass ejections of stars. These eruptive phenomena may cause significant impacts on space weather and planetary habitability. The contemporary time-domain survey missions such as the Kepler and TESS space telescopes can provide stellar light curve data with extremely large volume and high temporal resolution. These data greatly advanced our knowledge about the magnetic activity and flares of stars. The statistical and case analyses demonstrate the connections between the solar and stellar magnetic activity and eruptive phenomena in various aspects. These studies also reveal the different magnetic activity properties along with the age, rotation rate, spectral type, evolution stage, and other parameters of stars.
The physical models and imaging observations of the Sun can provide a framework basis for investigating the physical mechanism of stellar magnetic activity and eruptive phenomena. The knowledge of the stars can extend our physical view of the magnetic activity and eruptive phenomena on the Sun. This Research Topic invites Review and Original Research articles on any subjects concerning the solar-stellar magnetic activity and eruptive phenomena.
Keywords: Stars, Magnetic activity, Flares, Mass ejections, Solar-stellar connection
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