IIA Institutional Repository: Recent submissions

  • 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 ...
  • Uncertainty principle limits on the cosmological constant 
    Sivaram, C (Springer, 1986-08)
    The identification of the cosmological constant term with the energy density of the vacuum enables lower and upper limits to be placed on its value. The upper limit arises from the constraint that the total zero-point ...
  • Effects of spacetime curvature and rotation on arrival times of pulses from fast pulsars 
    Kapoor, R. C; Datta, B (American Astronomical Society, 1986-12)
    General relativistic effects due to spacetime curvature and rotation on the arrival times of pulsar signals are investigated using a rotationally perturbed spherical metric. It is found that for the millisecond pulsar PSR ...
  • IRAS observations of R Cor Bor stars 
    Kameswara Rao, N; Nandy, K (Royal Astronomical Society, 1986-09)
    The IRAS observations of R Cr B, SU Tau and V 348 Sgr indicate the existence of a cool dust component of temperature about 30 K in R Cr B and SU Tau and less than or equal to 100 K in V 348 Sgr, in addition to the hot dust. ...
  • HF Doppler observations of small scale plasma motions in the equatorial electrojet 
    Sastri, J. H; Ramesh, K. B; Rao, J. V. S. V; Rao, D. R. K (The Royal Swedish Academy of Sciences, 1986-12)
    Recordings of the variations in phase path, P of reflections, at vertical incidence, from blanketing sporadic-E layers over Kodaikanal (dip 3.5°N) revealed small amplitude, quasi-sinusoidal oscillations of 45-180 s periods ...
  • Expanding chromospheres of late G and K supergiants 
    Mallik, S. G. V (Royal Astronomical Society, 1986-09)
    The radiative transfer problem in non-LTE moving atmospheres has been explicitly solved for Hα line profiles. These computations have been done for a schematic model of the line-forming region over a wide range of optical ...
  • The variation of the 5200 feature in HD 34452 
    Shylaja, B. S; Babu, G. S. D (Royal Astronomical Society, 1986-10)
    Spectrophotometric observations of the hot Si star HD 34452 = HR 1732 obtained over a duration of four years, from 1979 to 1983, are presented. The period of variation in the broad-band feature centred around λ5200 is found ...
  • General relativistic decollimation of a jet 
    Kapoor, R. C (Gordon and Breach Science Publishers, 1986)
    The effect of defocusing introduced by spacetime curvature in a narrow conical beam of particles emanating from the vicinity of a compact mass is considered, with application to the study of jets. The deflection in particle ...
  • Periodic modulations in the optical light curves of EX Hydrae 
    Seetha, S; Sharma, D. P; Padmini, V. N; Marar, T. M. K; Kasturirangan, K (Kluwer Academic Publishers, 1987-02)
    The authors present here new results on the periodic modulations in the optical light curves of EX Hydrae observed during 1982 - 84. The period analysis has been done using synchronous summation and discrete Fourier transform ...
  • Photometry of the Rs-Canum Binary II-PEG 
    Mohin, S; Raveendran, A. V; Mekkaden, M. V (International Astronomical Union, 1986)
    B and V photometry of II Peg obtained at Kavalur on 39 nights during 1980 - 81, 1981 - 82 and 1984 - 85 is presented. From an analysis of the available data on this object the authors find that no two light curves agree ...
  • Occultation of SAO 185428 by 336 Lacadiera 
    Paranjpye, A; Babu, G. S. D (Indian Academy of Sciences, 1986)
  • A spectrophotometric study of the Wolf-Rayet star HD 50896 
    Shylaja, B. S (Indian Academy of Sciences, 1986-12)
    New spectrophotometric observations of the Wolf-Rayet system HD 50896 are presented and interpreted in terms of its binary nature. The lines of N V, N IV and C IV show moderate variations which can be explained using a ...
  • A New Polarimeter for Stellar Polarization Measurement 
    Saxena, A. K (International Astronomical Union, 1986)
    A polarimeter for the measurement of Stokes' parameters for stellar and quasi stellar objects in specific wavelength regions has been reported. The variable retardation and dispersive property of a small angle Babinet ...
  • Minimum Relative Entropy Method - Solution to Missing Short Baseline Problem 
    Shevgaonkar, R. K (Indian Academy of Sciences, 1986-12)
    The minimum-relative-entropy method (MREM) is proposed as a solution to the missing short-baseline problem in radio synthesis observations. It is shown that a measure of distance between the prior model and the image in ...
  • A Single-Channel Polarimeter 
    Jain, S. K; Bhattacharyya, J. C (International Astronomical Union, 1986)
    The authors have developed a single-channel photopolarimeter to measure polarization to ≡1%, with an accuracy of 0.1%. Laboratory tests show that the performance of the instrument matches the requirements.
  • CN 1-1 - A peculiar compact planetary nebula 
    Bhatt, H. C; Mallik, D. C. V (The European Southern Observatory, 1986-11)
    Cn 1-1 is an emission-line object that shows strong emission lines characteristic of high density planetary nebulae superposed on the stellar spectrum of an F5 III-IV star. The authors estimate the absolute luminosity of ...
  • Variation of linear polarization in the R Aquarii system 
    Deshpande, M. R; Joshi, U. C; Kulshrestha, A. K; Sen, A. K; Kameswara Rao, N; Raveendran, A. V (Astronomical Society of the Pacific, 1987-01)
    Linear polarization measurements of the R Aqr system are reported here. The R Aqr system shows strong wavelength dependence of percent polarization and position angle, which are strongly time dependent also. There is a ...
  • Does sunspot activity originate in slow global oscillations of the sun? 
    Gokhale, M. H (Indian Academy of Sciences, 1986-12)
    A Fourier analysis of sunspot activity during the 1933-1954 period using data entending over the first 10 degrees and all azimuthal orders of the spherical harmonics is presented, and results suggest that the sunspot ...
  • Seya namioka monochromators theory and design of holographic concave grating 
    Singh, M; Reddy, G. P (Elsevier, 1986-11)
  • On the saturation of the refractive index structure function. I - Enhanced hopes for long baseline optical interferometry 
    Venkatakrishnan, P; Chatterjee, S (Royal Astronomical Society, 1987-01)
    The Kolomogorov- Obukhov law for the refractive index structure function is shown to be only an approximation valid in the inertial sub range of turbulence. The inclusion of saturation effects for larger separations leads ...

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