Butterfly Diagram and Other Properties of Plage Areas from Kodaikanal Ca ii K Photographs Covering 1904 - 2007.

Ca ii K observations of the Sun have a great potential for probing the Sun's magnetism and activity, as well as for reconstructing solar irradiance. The Kodaikanal Solar Observatory (KoSO) in India, houses one of the most prominent Ca ii K archives, spanning from 1904 to 2007, obtained under the same experimental conditions over a century, a feat very few other sites have achieved. However, the KoSO Ca ii K archive suffers from several inconsistencies (e.

Sun-like stars produce superflares roughly once per century.

Stellar superflares are energetic outbursts of electromagnetic radiation that are similar to solar flares but release more energy, up to 10 erg on main-sequence stars. It is unknown whether the Sun can generate superflares and, if so, how often they might occur. We used photometry from the Kepler space observatory to investigate superflares on other stars with Sun-like fundamental parameters.

Global temperature modes shed light on the Holocene temperature conundrum.

Reconstructions of the global mean annual temperature evolution during the Holocene yield conflicting results. One temperature reconstruction shows global cooling during the late Holocene. The other reconstruction reveals global warming.

The Sun is less active than other solar-like stars.

The magnetic activity of the Sun and other stars causes their brightness to vary. We investigated how typical the Sun's variability is compared with other solar-like stars, i.e.

Publisher's Note: Solar Irradiance Variability is Caused by the Magnetic Activity on the Solar Surface [Phys. Rev. Lett. 119, 091102 (2017)].

This corrects the article DOI: 10.1103/PhysRevLett.119.

Solar Irradiance Variability is Caused by the Magnetic Activity on the Solar Surface.

The variation in the radiative output of the Sun, described in terms of solar irradiance, is important to climatology. A common assumption is that solar irradiance variability is driven by its surface magnetism. Verifying this assumption has, however, been hampered by the fact that models of solar irradiance variability based on solar surface magnetism have to be calibrated to observed variability.