ET Dra activity according to observations in 2018–2023

Cover Page

Cite item

Full Text

Open Access Open Access
Restricted Access Access granted
Restricted Access Subscription Access

Abstract

The results of new photometric observations of the chromospherically active star ET Dra, performed using telescopes of the Zvenigorod INASAN Observatory, the Russian-Cuban Observatory in the territory of the Republic of Cuba (Havana) and the Terskol INASAN Observatory (a total of 8 sets of observations), as well as the addition of archival observations of the Kamogata Wide-field Survey. According to the data received during 2018–2023 changes in the shape of the light curve caused by the rotational modulation of a star with spots on the surface, as well as studies of the long-term variability of the star’s brightness were investigated. Characteristic changes in the ET Dra light curve are noted including a decrease of the stellar brightness in V filter, its cyclic changes and subsequent brightness increase. The shape of the phase curve and the duration of the extended minimum of brightness vary. During the HJD 245 9670 – 245 9715 interval the amplitude of the star’s brightness variability reached a maximum value of more than 0.4 magnitude, as it was in 1990. For each of the 8 set of observations the surface temperature inhomogeneities map were calculated and estimates of the spotedness parameter S of the object were performed. Maximum value of parameter S was 32.2–33.5%. Based on the constructed power spectra the values of possible cycles of long-term activity of the star are obtained as 570 and 1160 days (1.56 and 3.18 years).

About the authors

I. S. Savanov

Institute of Astronomy of the Russian Academy of Sciences

Author for correspondence.
Email: igs231@mail.ru
Russian Federation, Moscow

S. A. Naroenkov

Institute of Astronomy of the Russian Academy of Sciences

Email: igs231@mail.ru
Russian Federation, Moscow

M. A. Nalivkin

Institute of Astronomy of the Russian Academy of Sciences

Email: igs231@mail.ru
Russian Federation, Moscow

A. N. Tarasenkov

Institute of Astronomy of the Russian Academy of Sciences

Email: igs231@mail.ru
Russian Federation, Moscow

E. S. Dmitrienko

Lomonosov Moscow State University, Sternberg Astronomical Institute

Email: igs231@mail.ru
Russian Federation, Moscow

References

  1. B. W. Bopp and R. E. Stencel, 247, L131 (1981).
  2. V. B. Puzin, I. S. Savanov, I. I. Romanyuk, E. A. Semenko, and E. S. Dmitrienko, Astrophys. Bull. 69(3), 321 (2014).
  3. V. B. Puzin, I. S. Savanov, and E. S. Dmitrienko, Astron. Rep. 61(8), 693 (2017).
  4. J. Sikora, J. Rowe, S. B. Howell, E. Mason, and G. A.Wade, Monthly Not. Roy. Astron. Soc. 496(1), 295 (2020).
  5. C. W. Ambruster, F. C. Fekel, E. F. Guinan, and B. J. Hrivnak, 479(2), 960 (1997).
  6. L. Jetsu, R. Anttila, E. Dmitrienko, K. N. Grankin, J. Huovelin, S. Y. Mel’nikov, V. S. Shevchenko, and I. Tuominen, Astron. and Astrophys. 262, 188 (1992).
  7. I. S. Savanov, S. A. Naroenkov, M. A. Nalivkin, and E. S. Dmitrienko, Astrophysics 62(3), 313 (2019).
  8. I. S. Savanov, S. V. Karpov, G. M. Beskin, A. V. Biryukov, et al., Astrophys. Bull. 77(4), 422 (2022).
  9. I. S. Savanov, S. A. Naroenkov, M. A. Nalivkin, and E. S. Dmitrienko, Astron. Rep. 67(12), 1394 (2023).
  10. I. S. Savanov and K. G. Strassmeier, Astron. Nachricht. 329(4), 364 (2008).
  11. K. G. Strassmeier, R. Briguglio, T. Granzer, G. Tosti, et al., Astron. and Astrophys. 490(1), 287 (2008).
  12. I. S. Savanov and E. S. Dmitrienko, Astron. Rep. 56(2), 116 (2012).
  13. I. S. Savanov and K. G. Strassmeier, Astron. and Astrophys. 444(3), 931 (2005).
  14. V. Y. Terebizh, Astron. Astrophys. Trans. 23(2), 85 (2004), arXiv:math-ph/0412036.
  15. S. V. Berdyugina, Astron. and Astrophys. 338, 97 (1998).
  16. W. H. Press, S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, Numerical recipes in FORTRAN. The art of scientific computing (1992).
  17. A. Claret and J. Southworth, Astron. and Astrophys. 674, id. A63 (2023), arXiv:2305.01704 [astro-ph.SR].

Supplementary files

Supplementary Files
Action
1. JATS XML

Copyright (c) 2024 The Russian Academy of Sciences