arXiv subjects

E. A. Bruevich

Publications and source records attributed to E. A. Bruevich.

25 records · Page 2Linked to original sources

arXiv2012

Cycles of the magnetic activity of the Sun and solar-type stars and simulation of their fluxes

The application of the Wavelet analysis and Fourier analysis to the dataset of variations of radiation fluxes of solar-like stars and the Sun is examined. In case of the Sun the wavelet-analysis helped us to see a set of values of periods of cycles besides "11-year" cycle: the long-duration cycles of 22-year, 40-50 year and 100-120 year and short-duration cycles of 2-3,5 years and 1,3-year. We present a method of the chromospheric flux simulation using the 13 late-type stars, which have well-determined cyclic flux variations similar to the 11-year solar activity cycle. Our flux prediction is based on the chromospheric calcium emission time series measurements from the Mount Wilson Observatory and comparable solar dataset. We show that solar three - component modeling well explains the stellar chromospheric observations.

astro-ph.SR↗

arXiv2011

On cyclic activity of the Sun and solar-type stars

The cyclicity of 33 solar-type stars that are similar to 11-year and to the quasi-biennial variations of solar radiation have studied. Our calculation were based on new simultaneous observations of the flux variations of the photospheric and chromospheric emissions of 33 solar-type stars and the Sun during the HK project that were conducted over the last 20 years. The method of Fast Fourier Transform was applied to these observed data. In addition to the known cyclic chromospheric emission variations of stars at the 11-year time scale, which were discovered at the Mount Wilson Observatory, we found a recurrences on the quasi-biennial time scale. The results of calculations of periods of the star's fluxes variations at the 11-year and quasi-biennial time scales are presented

astro-ph.SR↗

arXiv2011

Solar Activity Indices in 21, 22 and 23 Cycles

The monthly average values of the main solar activity indices such as Wolf numbers (W), 10,7 cm radio flux (F10,7), 0,1-0,8 nm background, total solar irradiance and Mg II UV-index (280 nm core to wing ratio) were studied for 23 activity cycle. The correlation coefficients of linear regression for main solar activity indices versus F10,7 were analyzed for every year of 23 activity cycle. All the correlation coefficients for 23 activity cycle have the minimum values in 2001. We also analyzed the connection between monthly average values of the most popular indices W and F10,7 for 21, 22 and 23 solar activity cycles. The values of every year linear regression correlation coefficients for W versus F10,7 show the cyclic variations with period closed to half path of so-called 11-year period of solar activity.

astro-ph.SR↗

arXiv2011

Solar and Solar-type Stars Atmosphere's Activity at 11-year and Quasi-biennial Time Scales

We studied new simultaneous observations of the flux variations of the photospheric and chromospheric emissions of 33 solar-type stars and Sun during the HK-project that were conducted over the past 20 years. In addition to the known cyclic chromospheric emission variations of stars at the 11-year time scale, which were discovered at the Mount Wilson Observatory, we found a recurrences that are similar to the quasi-biennial variations of solar radiation. The results of calculations of the radiation fluxes variations periods of stars at the quasi-biennial scale are given.

astro-ph.SR↗

arXiv2010

Spotting in stars with a low level of activity, cloze to solar activity

Data on the variability of the continuum optical emission are used for the first time to estimate the degree of spotting in stars similar to that of the sun. It is sown that the amount of spotting increases gradually from the sun to the highly spotted stars for which Alekseev and Gershberg constructed the zonal model for the distributions of spots. A close relationship is found between spotting and the power of the x-ray emission from the stars with widely varying levels of activity.

astro-ph.SR↗

arXiv2010

On Chromospheric Variations Modeling for Main-Sequence Stars of G and K Spectral Classes

We present a method of chromospheric flux simulation for 13 late-type main-sequence stars. These Sun-like stars have well-determined cyclic flux variations similar to 11 yr solar activity cycle. Our flux prediction is based on chromospheric HK emission time series measurements from Mount Wilson Observatory and comparable solar data. We show that solar three - component modeling explains well the stellar observations. We find that the 10 - 20% of K - stars disc surfaces are occupied by bright active regions.

astro-ph.SR↗

arXiv2010

On laminar convection in solar type stars

We present a new model of large-scale multilayer convection in solar type stars. This model allows us to understand such self-similar structures observed at solar surface as granulation, supergranulation and giant cells. We study the slow-rotated hydrogen star without magnetic field with the spherically-symmetric convective zone. The photon's flux comes to the convective zone from the central thermonuclear zone of the star. The interaction of these photons with the fully ionized hydrogen plasma with $T>10^5K$ is carried out by the Tomson scattering of photon flux on protons and electrons. Under these conditions plasma is optically thick relative to the Tomson scattering. This fact is the fundamental one for the multilayer convection formation. We find the stationary solution of the convective zone structure. This solution describes the convective layers responsible to the formation of the structures on the star's surface.

astro-ph.SR↗