相关论文: The butterfly diagram in the 18th century

The original sunspot observations by Heinrich Samuel Schwabe of 1825-1867 were digitized and a first subset of spots was measured. In this initial project, we determined more than 14 000 sunspot positions and areas comprising about 11% of…

Because of the lack of reliable sunspot observation, the quality of sunspot number series is poor in the late 18th century, leading to the abnormally long solar cycle (1784--1799) before the Dalton minimum. Using the newly recovered solar…

Most of our knowledge about the Sun's activity cycle arises from sunspot observations over the last centuries since telescopes have been used for astronomy. The German astronomer Gustav Sp\"orer observed almost daily the Sun from 1861 until…

The number of spots on the surface of the Sun is one of the best tracers of solar variability we have. The sunspot number is not only known to change in phase with the 11-year solar cycles, but also to show variability on longer time…

Digital images of the observations printed in the books "Rosa Ursina sive solis" and "Prodromus pro sole mobili" by Christoph Scheiner as well as the drawings from Scheiner's letters to Marcus Welser are analysed in order to obtain…

The sunspot drawings of Johann Staudacher of 1749--1799 were used to determine the solar differential rotation in that period. These drawings of the full disk lack any indication of their orientation. We used a Bayesian estimator to obtain…

Stellar magnetic fields are poorly understood but are known to be important for stellar evolution and exoplanet habitability. They drive stellar activity, which is the main observational constraint on theoretical models for magnetic field…

We use the historic record of sunspot groups compiled by the Royal Greenwich Observatory together with the sunspot number to derive the statistical properties of sunspot group emergence in dependence of cycle phase and strength. In…

Sunspot groups observed by Royal Greenwich Observatory/US Air Force/NOAA from May 1874 to November 2008 and the Carte Synoptique solar filaments from March 1919 to December 1989 are used to investigate the relative phase shift of the paired…

The butterfly diagram of the solar cycle is the equatorward migration of the emergence latitudes of sunspots as the solar cycle evolves. Revealing the mechanism for the butterfly diagram is essential for understanding the solar and stellar…

Samuel Heinrich Schwabe made 8486 drawings of the solar disk with sunspots in the period from November 5, 1825 to December 29, 1867. We have measured sunspot sizes and heliographic positions on digitized images of these drawings. A total of…

R. C. Carrington, C. H. F. Peters, and W. de la Rue observed the sunspots in the second half of the 19th century, determining their heliographic positions between 1853 and 1870, before the establishment of the solar program of the Royal…

We analyze photometric data of the active RS CVn--type star HR 1099 for the years 1975--2006 with an inversion technique and reveal the nature of two activity cycles of 15--16 yr and 5.3$\pm$0.1 yr duration. The 16 yr cycle is related to…

The difference between individual solar cycles in the magnetic butterfly diagram can mostly be ascribed to the stochasticity of the emergence process. We aim to obtain the expectation value of the butterfly diagram from observations of four…

The butterfly diagram of the solar cycle exhibits a poleward migration of the diffuse magnetic field resulting from the decay of trailing sunspots. It is one component of what is sometimes referred to as the "rush to the poles". We…

Using neural networks as a prediction method, we attempt to demonstrate that forecasting of the Sun's sunspot time series can be extended to the spatial-temporal case. We employ this machine learning methodology to forecast not only in time…

In 1844 Schwabe discovered that the number of sunspots increased and decreased over a period of about 11 years, that variation became known as the sunspot cycle. Almost eighty years later, Hale described the nature of the Sun's magnetic…

This research work is based on the study of the longitudinal distribution of the most active sunspot zones on the photosphere. Sunspot data has been analyzed for 12 solar cycles (cycles 12-23) separately for northern and southern…

Hand-drawn synoptic maps from the Meudon Observatory (1919 onwards) and the McIntosh archive (1967 onwards) are two important sources of long-term, manually recorded filament observations. In this study, we calibrate the Meudon maps and…

During the solar magnetic activity cycle the emergence latitudes of sunspots change, leading to the well-known butterfly diagram. This phenomenon is poorly understood for other stars as starspot latitudes are generally unknown. The related…