IIA Institutional Repository

Browsing IIAP Publications by Subject "Calcium"

Browsing IIAP Publications by Subject "Calcium"

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  • Analysis of Ca(+) K plage area for short period variation 
    Singh, J; Jain, S. K (Indian Academy of Sciences, 1989-12)
    Observations of solar Ca(+) K daily plage area from 1951 to 1977 are analyzed to search for short-period (12-13 day) variations. The 27-day periodicity due to solar rotation modulation is found at all latitudes. Using an ...
  • CA II K2V spectral features and their relation to small-scale photospheric magnetic fields 
    Sivaraman, K. R; Livingston, W. C (D. Reidel Publishing Co.,, 1982-10)
    Although the Ca ii K232 network is known to be cospatial with magnetic elements there has been doubt as to the magnetic origin of the fainter K2V points. We demonstrate that weak magnetic elements also lie at the roots of ...
  • Calibration on the Sun for stellar magnetic fields 
    Sivaraman, K. R; Bagare, S. P; Gupta, S. S; Kariyappa, R (Springer, 1987-07)
    The intimate association between the surface magnetic fields and the Ca II K-line emission known to exist on the Sun, holds a promise for using this property to detect the presence of global magnetic fields on Sun-like ...
  • Chromospheric CA II K-line variations in the sun as a star over a solar cycle 
    Sivaraman, K. R; Singh, J; Bagare, S. P; Gupta, S. S (American Astronomical Society, 1987-02)
    The disk-averaged Ca II K profiles obtained at the Kodaikanal solar tower telescope for the period 1969-1984 are used to study the chromospheric variations in the sun as a star. The 1A index shows increases of 18 and 28 ...
  • Do polar faculae on the sun predict a sunspot cycle? 
    Makarov, V. I; Makarova, V. V; Sivaraman, K. R (Springer, 1989-03)
    The paper reports the results of the analysis of the data on polar faculae for three solar cycles (1960–1986) at the Kislovodsk Station of the Pulkovo Observatory and on polar bright points in Ca ii K line for two solar ...
  • Relativistic coupled-cluster studies of ionization potentials, lifetimes, and polarizabilities in singly ionized calcium 
    Sahoo, B. K; Das, B. P; Mukherjee, D (The American Physical Society, 2009-05)
    Using the relativistic coupled-cluster method, we have calculated ionization potentials, electric dipole transition amplitudes, and dipole polarizabilities of many low-lying states of Ca/sub+. Contributions from the Breit ...
  • Spectral lines behavior of Be I and Na I isoelectronic sequence in Debye plasma environment 
    Chaudhuri, R. K; Chattopadhyay, S; Mahapatra, U. S (American Institute of Physics, 2012-08)
    We report the plasma screening effect on the first ionization potential (IP) and [He]2s/sup2/ (/sup1/S/sup0/)→[He]2s2p/2s3p allowed (/sup1/P/sub1/) and inter-combination transitions (/sup3/P/sub1/) in some selected Be-like ...
  • Study of calcium-K network evolution from Antarctica 
    Singh, J; Nagabhushana, B. S; Babu, G. S. D; Uddin, Wahab (Springer, 1994-08)
    To study the evolution of large convective cells known as supergranules, a solar telescope was set up at Maitri, Indian permanent station in Antarctica region, during the local summer months (December 1989 through March ...
  • Unusual extinction profiles by Rayleigh scattering 
    Shah, G. A (WILEY-VCH Verlag Berlin GmbH & Co, 1977)
    The extinction efficiencies for small smooth metallic particles (granules) have been calculated using rigorous Mie theory of scattering. Strong size-dependent resonances for spheres composed of sodium, potassium, and calcium ...
  • Variability of the solar chromospheric network over the solar cycle 
    Kariyappa, R; Sivaraman, K. R (Springer, 1994-06)
    From a large sample of the Kodaikanal spectroheliograms in the Ca II K line we have studied the variations in the intensity of the network elements over two solar cycles and have estimated their contribution to the overall ...
  • Variations in the solar rotation rate derived from Ca(+) K plage areas 
    Singh, J; Prabhu, T. P (Springer, 1985-11)
    Daily calcium plage areas for the period 1951-1981 (which include the solar cycle 19 and 20) have been used to derive the rotation period of the sun at latitude belts 10-15 deg N, 15-20 deg N, 10-15 deg S, and 15-20 deg ...

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