IIAP Publications: Recent submissions

  • Time variability of the He I 10830 A line profile 
    Singh, J; Jain, S. K; Venkatakrishnan, P (Springer, 1994-03)
    We have studied the time-dependent behavior of the He I 10830 A line. These studies show that (1) the fluctuations of the line width are uncorrelated with the equivalent-width fluctuations and (2) the autocorrelation curves ...
  • Vlasov-Maxwell equilibria of solar coronal loops 
    Krishan, V; Sreedharan, T. D; Mahajan, Swadesh M (Royal Astronomical Society, 1991-04)
    A Vlasov-Maxwell description of the ubiquitous solar coronal structures is presented. It is found that an equilibrium plasma configuration can live with spatial gradients in density, temperature, current and drift speeds ...
  • A new discussion on the M(v) - W(O I 7774 A) relationship for F-G stars in the light of high-resolution data 
    Arellano Ferro, A; Giridhar, S; Goswami, A (Royal Astronomical Society, 1991-05)
    High-resolution CCD data and a large group of F-G stars of fundamentally determined distances are used here to investigate the intrinsic nature of the M(v) - W(O I) relation and the effect of other atmospheric parameters ...
  • H-alpha flare of 14 March, 1984 -- Evidence for reconnection? 
    Sundararaman, K; Aleem, S. M; Singh, J; Selvendran, R; Thiagarajan, R (Springer, 1994-01)
    Kodaikanal H-alpha monochromatic and white-light observations are used to study the circular flare of 14 March, 1984. We report here the dynamic activity of the H-alpha filament, which attained a severe twist before erupting ...
  • A model of solar granulation through inverse cascade 
    Krishan, V (Royal Astronomical Society, 1991-05)
    Nonlinear interactions between small fluid elements in an energetically open system facilitate the formation of large coherent stable structures. This is known as self-organization. Solar granulation on all scales is ...
  • Clustering of galaxies by inverse cascade in a turbulent medium 
    Krishan, V; Sivaram, C (Royal Astronomical Society, 1991-05)
    A definite physical mechanism based in inverse cascading is suggested which quite naturally yields a bottom-up hierarchical structure for galactic clustering. In this mechanism, nonlinear interactions between small fluid ...
  • Observations of the continuum radio emission from the undisturbed Sun at a wavelength of 8.7 meters 
    Sastry, Ch. V (Springer, 1994-03)
    We have mapped the continuum emission from the undisturbed Sun at a wavelength of 8.7 m during 1981-1985 using the large decameter-wave radio telescope at Gauribidanur, India with a resolution of 26 x 38 arc min. During ...
  • The radio brightness of the undisturbed outer solar corona in the presence of a radial magnetic field 
    Golap, K; Sastry, Ch. V (Springer, 1994-03)
    The radio brightness of the quiet outer solar corona at a frequency of 35 MHz in the presence of a radial magnetic field is computed. It is found that the brightness temperature of the ordinary radiation increases ...
  • SAO 75669: A late type giant behind the molecular cloud MBM 12 
    Bhatt, H. C; Sagar, R; Subramaniam, A; Gorti, U; Chandrasekhar, T; Ashok, N. M; Ragland, S (European Southern Observatory, 1994-09)
    Photometric and spectroscopic observations of the star SAO 75669 in the region of the high galactic latitude molecular cloud MBM 12 are presented. The optical, near-infrared and far-infrared IRAS photometric magnitudes ...
  • Density and temperature diagnostics of solar emission lines from NA VII and AL IX 
    Raju, P. K; Dwivedi, B. N; Gupta, A. K (Springer, 1994-02)
    Line intensity ratios of extreme ultraviolet (EUV) emission lines from Na VII and Al IX have been considered for electron density and temperature determinations within the chromosphere-corona transition region and the ...
  • Mutual phenomena of Jovian satellites 
    Vasundhara, R (Indian Academy of Sciences, 1991-03)
    Mutual eclipses of Galilean satellites were observed and the results are given. The observations are fitted by utilizing Lambert's law, theoretical models assuming a uniform disk, and Lommel-Seeliger's law which describes ...
  • Dust and ionized gas in NGC 3607 
    Singh, K. P; Prabhu, T. P; Kembhavi, A. K; Bhat, P. N (The American Astronomical Society, 1994-04)
    We report the detection of a broad dust ring in the X-ray-bright elliptical galaxy NGC 3607, the dominant member of a nearby group of galaxies. The inner radius of the ring is approximately 1.3 kpc from the nucleus and has ...
  • Resonance line polarization in spherical atmospheres: Partial redistribution effects studied with the Domke-Hubeny redistribution matrix 
    Nagendra, K. N (The American Astronomical Society, 1994-09)
    The problem of resonance line polarization including collisional redistribution is studied using simple theoretical models. The medium is assumed to be a static finite spherical shell atmosphere. The purpose of this paper ...
  • Aberration and advection effects in expanding spherically symmetric shells 
    Peraiah, A (American Astronomical Society, 1991-04)
    The extreme outer layers of supernovae, novae, AGN, QSOs, and many supergiant stars are known to be in rapid expansion or contraction. In this paper, aberration and advection effects in a spherical medium scattering radiation ...
  • 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 ...
  • An investigation of polarization produced by circumstellar dust envelopes 
    Raveendran, A. V (European Southern Observatory, 1991-03)
    Numerical computations show that: (1) the polarimetric behavior of carbon stars is inconsistent with the scattering by graphite grains, (2) the radial pulsation of the star does not significantly change the net polarization ...
  • BVRI polarimetry of carbon stars 
    Raveendran, A. V (European Southern Observatory, 1991-03)
    BVRI polarimetry of carbon stars belonging to different variability types - VX And, UU Aur, T Cae, Y CVn, U Hya, Y Hya, RY Mon, W Ori, Y Per, RT Pup, and X Vel - is presented. Though there is significant scatter, on the ...
  • Heating of the quiet solar chromosphere. 1: Role of the inner network bright points 
    Kariyappa, R; Sivaraman, K. R; Anandaram, M. N (Springer, 1994-05)
    We have analyzed a large number of Ca II H line profiles at the sites of the bright points in the interior of the network using a 35-min-long time sequence of spectra obtained at the Vacuum Tower Telescope (VTT) of the ...
  • Effect of Lyman radiation transfer on the formation of the H-alpha line in supergiant chromospheres 
    Mallik, S. G. V; Mallik, D. C. V; Mohan Rao, D (European Southern Observatory, 1991-03)
    The paper pesents radiative transfer calculations of the H-alpha line in spherically expanding chromospheres of late-type supergiants where the assumption of radiative detailed balance in Lyman transitions has been relaxed. ...
  • Resonance-Line Polarization in Expanding Spherical Atmospheres - Solution in the Comoving Frame 
    Sengupta, S (Royal Astronomical Society, 1994-07)
    The effect of differential radial velocity in the distribution of line intensities and line polarization along the line of sight of an extended stellar atmosphere has been studied. The medium is assumed to be inhomogeneous, ...

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