Parameters of Starspots on the Surface of the Red Dwarf V647 Her

IF 0.7 4区地球科学 Q4 GEOCHEMISTRY & GEOPHYSICS

Geomagnetism and Aeronomy Pub Date : 2025-02-14 DOI:10.1134/S0016793224700464

N. I. Bondar’, I. Yu. Alekseev, K. A. Antonyuk, N. V. Pit’

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Abstract

Based on the available photometric data for the star V647 Her, including those obtained from photographic archives, we considered the yearly-mean brightness variability over the time interval 1939–2022. The dense data series obtained in 2019 and 2022 at CrAO as well as the sample for 2004 from the SuperWASP catalog showed changes in light curves and in color indices of the star with a period of 20.69 days. Changes in the V–I color index indicate the presence of cool spots on its surface. The parameters of starspots were calculated within the zonal model for each year and it was found that the temperature of the spots is 500–600 K lower than the temperature of the quiet photosphere with T_eff = 3300 K, the spots occupy from 8 to 30% of the entire surface of the star in different years. The spottedness of the star’s photosphere is an indicator of its activity, and according to the interval between the epochs of minimum spottedness, we derived a characteristic time between the minima in activity of V647 Her of about 60 years, and the duration of the maximum of activity of about 5 years.

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来源期刊

Geomagnetism and Aeronomy Earth and Planetary Sciences-Space and Planetary Science

CiteScore

1.30

自引率

33.30%

发文量

审稿时长

4-8 weeks

期刊介绍： Geomagnetism and Aeronomy is a bimonthly periodical that covers the fields of interplanetary space; geoeffective solar events; the magnetosphere; the ionosphere; the upper and middle atmosphere; the action of solar variability and activity on atmospheric parameters and climate; the main magnetic field and its secular variations, excursion, and inversion; and other related topics.