Abstract
We report on the detection of rapid variability in subsecond mode in the Balmer lines of hydrogen, lines Ca II H,K, and b Mg I triplet in chromospherically active stars 61 Cyg A, B. The spectral observations of 61 Cyg A, B were performed with MMCS spectrograph in Cassegrain’s focus of the 2-m telescope at peak Terskol (R = 13000), with a grating spectrograph mounted on a 60-cm telescope at peak Terskol (R ≈ 100), and a 60-cm telescope of the Andrushivka Observatory (R ≈ 200). The observations were carried out in the framework of international campaign of observations of variable stars using the Synchronous Network of Telescopes. The high-resolution spectra were obtained with intervals of approximately 2 minutes. The low-resolution spectra were obtained with intervals from 2 to 3 seconds. Spectral monitoring lasted from 30 minutes to 2 hours. We found that chromospherically active dwarf stars 61 Cyg A, B, having extensional spots on their surfaces exhibit rapid variations in the hydrogen lines, lines CaII H, K of ionized calcium and chromospheric triplet b Mg I on a time scale from approximately 2 seconds to approximately 2 minutes. Variations in the intensity of lines range from 1.5% in the Balmer series of hydrogen to approximately 0.5% in the lines of b Mg I triplet. These variations are well described by the shot noise model in the form of random elementary pulses with the frequency of occurrence of a few fractions of events per second to a few events per second. Comparison of rapid variations in chromospheric lines with different time intervals demonstrates the transient nature of this activity both on short (subsecond) and long-time scales.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
N. E. Kobrinskii, Information Filters in Economics (Statistika, Moscow, 1978) [in Russian].
V. I. Tikhonov, Statistical Radio Engineering (Radio i Svyaz’, Moscow, 1982) [in Russian].
A. Hemoelmann, J. Robrade, J. H. M. M. Schmitt, et al., “Coronal activity cycles in 61 Cygni,” Astron. Astrophys. 460, 261–267 (2006).
G. A. Korn and T. M. Korn, Mathematical Handbook (McGraw-Hill, New York, 1968).
B. E. Zhilyaev, A. V. Sergeev, M. V. Andreev, et al., “Slitless spectrograph for small telescopes: First results,” Kinematics Phys. Celestial Bodies 29, 120–130 (2013).
B. E. Zhilyaev, I. A. Verlyuk, M. V. Andreev, et al., “Observations of high-frequency variability in the chromospherically active star V390 Aurigae,” Mon. Not. R. Astron. Soc. 436, 1986–1992 (2013).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © B.E. Zhilyaev, A.V. Bondar, M.V. Andreev, S.M. Pokhvala, Yu.M. Ivashchenko, V.M. Reshetnyk, V.N. Petukhov, O.A. Svyatogorov, I.A. Verlyuk, 2015, published in Kinematika i Fizika Nebesnykh Tel, 2015, Vol. 31, No. 6, pp. 3–15.
About this article
Cite this article
Zhilyaev, B.E., Bondar, A.V., Andreev, M.V. et al. High-frequency variations of spectral lines in cromospherically active stars 61 cyg AB. Kinemat. Phys. Celest. Bodies 31, 267–275 (2015). https://doi.org/10.3103/S0884591315060082
Received:
Published:
Issue Date:
DOI: https://doi.org/10.3103/S0884591315060082