• L. H. Deng

      Articles written in Journal of Astrophysics and Astronomy

    • The Relative Phase Asynchronization between Sunspot Numbers and Polar Faculae

      L. H. Deng J. Y. Song Y. Y. Xiang Y. K. Tang

      More Details Abstract Fulltext PDF

      The monthly sunspot numbers compiled by Temmer et al. and the monthly polar faculae from observations of the National Astronomical Observatory of Japan, for the interval of March 1954 to March 1996, are used to investigate the phase relationship between polar faculae and sunspot activity for total solar disk and for both hemispheres in solar cycles 19, 20, 21 and 22. We found that (1) the polar faculae begin earlier than sunspot activity, and the phase difference exhibits a consistent behaviour for different hemispheres in each of the solar cycles, implying that this phenomenon should not be regarded as a stochastic fluctuation; (2) the inverse correlation between polar faculae and sunspot numbers is not only a long-term behaviour, but also exists in short time range; (3) the polar faculae show leads of about 50–71 months relative to sunspot numbers, and the phase difference between them varies with solar cycle; (4) the phase difference value in the northern hemisphere differs from that in the southern hemisphere in a solar cycle, which means that phase difference also existed between the two hemispheres. Moreover, the phase difference between the two hemispheres exhibits a periodical behaviour. Our results seem to support the finding of Hiremath (2010).

    • The Hemispheric Asymmetry of Polar Faculae

      L. H. Deng Z. Q. Qu X. L. Yan T. Liu K. R. Wang

      More Details Abstract Fulltext PDF

      In this paper, the north–south (N–S) asymmetry of the polar faculae at relatively low (RLLs), relatively high (RHLs) as well as total latitudes (TLs) respectively, are investigated. It is found that

      the polar faculae behave in a different asymmetrical way at different latitudinal bands;

      the asymmetry of solar activity may be a function of latitudes, which is present not only in the low-latitude solar activity but also in the high-latitude solar activity;

      the N–S asymmetry of the polar faculae at TLs depends on that at RHLs, and the asymmetry of the polar faculae at RLLs only plays a modulatory role.

    • Phase Relationship Between Sunspot Number, Flare Index and Solar Radio Flux

      X. L. Yan L. H. Deng Z. Q. Qu C. L. Xu D. F. Kong

      More Details Abstract Fulltext PDF

      To understand better the variation of solar activity indicators originated at different layers of the solar atmosphere with respect to sunspot cycles, we carried out a study of phase relationship between sunspot number, flare index and solar radio flux at 2800 MHz from January 1966 to May 2008 by using cross-correlation analysis. The main results are as follows:

      The flare index and sunspot number have synchronous phase for cycles 21 and 22 in the northern hemisphere and for cycle 20 in the southern hemisphere.

      The flare index has a noticeable time lead with respect to sunspot number for cycles 20 and 23 in the northern hemisphere and for cycles 22 and 23 in the southern hemisphere.

      For the entire Sun, the flare index has a noticeable time lead for cycles 20 and 23, a time lag for cycle 21, and no time lag or time lead for cycle 22 with respect to sunspot number.

      The solar radio flux has a time lag for cycles 22 and 23 and no time lag or time lead for cycles 20 and 21 with respect to sunspot number.

      For the four cycles, the sunspot number and flare index in the northern hemisphere are all leading to the ones in the southern hemisphere.

      These results may be instructive to the physical processes of flare energy storage and dissipation.

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

© 2017-2019 Indian Academy of Sciences, Bengaluru.