Related papers: How does the solar chromospheric activity look lik…
The emission in the near ultraviolet Ca II H & K lines is modulated by stellar magnetic activity. Although this emission, quantified via the S-index, has been serving as a prime proxy of stellar magnetic activity for several decades, many…
Chromospheric differential rotation is a key component in comprehending the atmospheric coupling between the chromosphere and the photosphere at different phases of the solar cycle. In this study, we therefore utilize the newly calibrated…
Rotation is a significant characteristic of the Sun and other stars, and it plays an important role in understanding their dynamo actions and magnetic activities. In this study, the rotation of the solar chromospheric activity is…
Context. The radiative losses in the solar chromosphere vary from 4~kW~m$^{-2}$ in the quiet Sun, to 20~kW~m$^{-2}$ in active regions. The mechanisms that transport non-thermal energy to and deposit it in the chromosphere are still not…
Differential rotation is one of the basic characteristics of the Sun, and it plays an important role in generating the magnetic fields and its activities. We investigated rotation rate using chromospheric features such as plages, enhanced…
The study of the differential rotation in the chromosphere of the Sun is of significant importance as it provides valuable insights into the rotational behaviour of the solar atmosphere at higher altitudes and the coupling mechanism between…
We need to establish a correspondence between the magnetic structures generated by models and usual stellar activity indexes to simulate radial velocity time series for stars less active than the Sun. This is necessary to compare the…
Rotation is a prominent feature of the Sun, and it plays a crucial role in the generation and dynamic evolution of solar magnetic fields. The daily composite time series of Ca II K plage areas from 1907 February 1 to 2023 December 31 is…
The detection of Earth-like planets with the radial-velocity method is currently limited by the presence of stellar activity signatures. On rotational timescales, spots and plages (or faculae) are known to introduce different RV signals,…
Several observatories around the globe started regular full-disc imaging of the solar atmosphere in the Ca II K line in the early decades of the 20th century. These observations are continued today at a few sites with either old…
We have analysed the Ca-K images obtained at Kodaikanal Observatory as a function of latitude and time for the period of 1913 - 2004 covering the Solar Cycle 15 to 23. We have classified the chromospheric activity into plage, Enhanced…
Analysis of over 36 years of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates five components of the variation of the seven measured chromospheric parameters: (a) the solar cycle (period ~ 11 years), (b)…
By combining ground-based spectrographic observations of variability in the chromospheric emission from Sun-like stars with the variability seen in their eigenmode frequencies, it is possible to relate the changes observed at the surfaces…
Precise, high-cadence, long-term records of stellar spectral variability at different temporal scales lead to better understanding of a wide variety of phenomena including stellar atmospheres and dynamos, convective motions, and rotational…
Stellar activity can be observed at different wavelengths in a variety of different activity indicators. We investigated the correlation between coronal and chromospheric emissions by combining X-ray data from stars detected in the eROSITA…
The solar modulation effect of cosmic rays in the heliosphere is an energy-, time-, and particle-dependent phenomenon which arises from a combination of basic particle transport processes such as diffusion, convection, adiabatic cooling,…
Full disk observations of the solar chromosphere in the Ca II K line represent a valuable dataset for studies of solar magnetic activity. The S-index is widely used to investigate the magnetic activity of stars, however, its connection to…
It is well established that both total and spectral solar irradiance are modulated by variable magnetic activity on the solar surface. However, there is still disagreement about the contribution of individual solar features for changes in…
The analysis of the effect of the hysteresis, which manifests itself in an ambiguous relationship of radiation from the photosphere, chromosphere and corona on the rise and decline phases of the solar and stellar activity cycles have done.…
The relation between the intensity of chromospheric emissions and the photospheric magnetic field strength has been examined in several studies, but the effect of the magnetic field inclination on chromospheric emissions remains almost…