Magnetic cycles of Sun-like stars with different levels of coronal and chromospheric activity — comparison with the Sun

Shimanovskaya, E. V.; Bruevich, Vasiliy; Бруевич, Е. А.

doi:10.1088/1674-4527/16/9/148

Cited by 6 publications

(9 citation statements)

References 31 publications

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“…The most powerful flares observed on the sun eject immense energy into the surrounding space, roughly a fifth of the energy released by the sun per second (for comparison, this equals all the energy released by humanity over a million years at current rates). Among the stars with activity of the solar type (e.g., UV Cet-type flare stars), the sun has relatively low flare activity [1,2]. The current solar activity cycle 24 is currently approaching the lowest number of solar spots and other global indices.…”

Section: Introductionmentioning

confidence: 99%

Powerful Solar Flares in September 2017. Comparison with the Largest Flares in Cycle 24

Бруевич

Bruevich

2018

Astrophysics

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Solar flare activity in cycle 24 is studied. Satellite observations of x-ray fluxes from GOES-15 and UV emission lines from the SDO/EVE experiment are used. The most powerful flares of cycle 24 in classes X9.3 and X8.2 in September 2017 are compared with powerful flares in classes M5-X6.9. The times at which the fluxes in the 30.4 and 9.4 nm lines and in the 0.1-0.8 nm x-ray range begin to increase are compared for 21 of the large flares. The total energies arriving at the earth from flares in the 30.4 and 9.4 nm lines and in the 0.1-0.9 nm x-ray range, E 30.4 , E 9.4 , and E 0.1−0.8 , from 25 flares during 2011 and 2012 are calculated. It is shown that the calculated energies of the flares in the analyzed lines from SDO/EVE and in the x-ray range from GOES-15 are closely interrelated.

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Section: Introductionmentioning

confidence: 99%

Powerful Solar Flares in September 2017. Comparison with the Largest Flares in Cycle 24

Бруевич

Bruevich

2018

Astrophysics

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“…A comparative analysis of chromospheric, coronal and cyclic activity of the Sun and Sun-like stars of F, G and K spectral classes from these different observational Programs shows the similar characteristics of magnetic cycles on the Sun and on the Sun-like stars, see [9], [10].…”

Section: Introductionmentioning

confidence: 89%

“…The standard algorithm of wavelet analysis as applied to astronomical observations of the Sun and stars was discussed in detail in [15], [20]. The choice of the Daubechies and Morlet wavelets as the best mother wavelets ψ(t) for astronomical data processing is discussed in [10], [21] on the basis of comparative analysis of results obtained using different mother wavelets.…”

Section: Observations Of Magnetic Cycles Of Hk-project Starsmentioning

confidence: 99%

“…The periods of the quasi- Using methods of frequency analysis of signals, the quasi-biennial cycles have been studied not only for the relative sunspot number, but also for 10.7 cm solar radio emission and for some other indices of solar activity, see [3]. It was also shown that the cyclicity on the quasi-biennial time scale often takes place among stars with 11-yr cyclicity, see [10,14].…”

Section: Observations Of Magnetic Cycles Of Hk-project Starsmentioning

confidence: 99%

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Evolution of the cycles of magnetic activity of the Sun and Sun-like stars in time

Bruevich,

Artamonov

2016

Preprint

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We applied the method of continuous wavelet-transform to the timefrequency analysis to the sets of observations of relative sunspot numbers, sunspot areas and to 6 Mount Wilson HK-project stars with well-defined magnetic cycles. Wavelet analysis of these data reveals the following pattern: at the same time there are several activity cycles whose periods vary widely from the quasi-biennial up to the centennial period for the Sun and vary significant during observations time of the HK-project stars. These relatively low-frequency periodic variations of the solar and stellar activity gradually change the values of periods of different cycles in time. This phenomenon can be observed in every cycles of activity.

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“…As opposed to most stars of the sun's type, the sun is characterized by comparatively low spottedness, moderate flare activity, and a low level of corona emission flux [2,3].…”

Section: Features Of Activity Cycle 24mentioning

confidence: 99%

Flare Activity of the Sun and Variations in its UV Emission During Cycle 24

Бруевич

Yakunina

2017

Astrophysics

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Abstract. The flare activity and the ultraviolet emission of the sun during its 24-th cycle are analysed. As compared to cycles 21-23, where the most powerful flares were observed during the decay phase, in cycle 24 the greatest number of powerful flares (>X2.7) occurred in the rising phase and at the maximum with the exception of the two largest flares of cycle 24 X9.3 and X8.2 in September 2017. We showed that regression fits of solar UV indices to the overall radiation level from the sun are substantially different for cycle 24 compared to cycles 21-23. It is found that for the flare of August 9, 2011 (SDO and GOES-15 observations), the flare propagates in a direction from the upper corona to the transition region and to the chromosphere. A study of the N-S asymmetry in the distribution of the flares in cycle 24 reveals a strong predominance of flares in the N-hemisphere in 2011 and in the S-hemisphere in 2014. It is also found that during cycles 23 and 24, the delays in the onset of proton events relative to the onset of the flares that cause them have a distribution with a distinct maximum corresponding to a delay of 2 hours for protons with energies >10 MeV, as well as for those with energies >100 MeV.

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Magnetic cycles of Sun-like stars with different levels of coronal and chromospheric activity — comparison with the Sun

Cited by 6 publications

References 31 publications

Powerful Solar Flares in September 2017. Comparison with the Largest Flares in Cycle 24

Powerful Solar Flares in September 2017. Comparison with the Largest Flares in Cycle 24

Evolution of the cycles of magnetic activity of the Sun and Sun-like stars in time

Flare Activity of the Sun and Variations in its UV Emission During Cycle 24

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