Changing stellar activity cycles

K. Oláh, K. G. Strassmeier, T. Granzer, W. Soon, S. L. Baliunas

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We investigated continuous long-term photometric datasets of thirteen active stars, Ca II variability of one single mainsequence star, and 10.7cm radio data of the Sun, with simple Fourier- and time-frequency analysis. The data reflect the strength of the activity manifested in magnetic spots. All studied stars show multiple (2 to 4) cycles of different lengths. The time-frequency analysis reveals, that in several cases of the sample one or two of the cycles exhibit continuous changes (increase or decrease). For four stars (V711 Tau, IL Hya, HK Lac, HD 100180) and for the Sun we find that the cycle length changes are strong, amounting to 10-50% during the observed time intervals. The cycle lengths are generally longer for stars with longer rotational periods.

Original languageEnglish
Pages (from-to)1072-1074
Number of pages3
JournalAstronomische Nachrichten
Volume328
Issue number10
DOIs
Publication statusPublished - Oct 2007

Fingerprint

stellar activity
frequency analysis
stars
cycles
sun
radio
intervals

Keywords

  • Stars: activity
  • Stars: atmospheres
  • Stars: late-type
  • Stars: magnetic fields
  • Starspots

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Oláh, K., Strassmeier, K. G., Granzer, T., Soon, W., & Baliunas, S. L. (2007). Changing stellar activity cycles. Astronomische Nachrichten, 328(10), 1072-1074. https://doi.org/10.1002/asna.200710839

Changing stellar activity cycles. / Oláh, K.; Strassmeier, K. G.; Granzer, T.; Soon, W.; Baliunas, S. L.

In: Astronomische Nachrichten, Vol. 328, No. 10, 10.2007, p. 1072-1074.

Research output: Contribution to journalArticle

Oláh, K, Strassmeier, KG, Granzer, T, Soon, W & Baliunas, SL 2007, 'Changing stellar activity cycles', Astronomische Nachrichten, vol. 328, no. 10, pp. 1072-1074. https://doi.org/10.1002/asna.200710839
Oláh K, Strassmeier KG, Granzer T, Soon W, Baliunas SL. Changing stellar activity cycles. Astronomische Nachrichten. 2007 Oct;328(10):1072-1074. https://doi.org/10.1002/asna.200710839
Oláh, K. ; Strassmeier, K. G. ; Granzer, T. ; Soon, W. ; Baliunas, S. L. / Changing stellar activity cycles. In: Astronomische Nachrichten. 2007 ; Vol. 328, No. 10. pp. 1072-1074.
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