IIA Institutional Repository: Recent submissions

  • A New Digital Display System for the 1-meter Telescope at Vainu Bappu Observatory 
    Srinivasan, R; Naidu, B. N (Astronomical Society of the Pacific, 1997-01)
    The Carl-Zeiss 1-meter telescope at Vainu Bappu Observatory uses synchro transmitters as angular transducers in a 3-stage geared train for the two axes coordinate display system. Synchro receivers are used in the console ...
  • High-resolution spectroscopy of R CrB - pulsations, shells and mass loss 
    Kameswara Rao, N; Lambert, D. L (The Royal Astronomical Society, 1997-01)
    High spectral resolution observations obtained in 1994 and spanning three pulsation cycles of R CrB are discussed along with available UBV photometric observations for the same epochs. Model atmosphere based analyses of ...
  • BVRI photometry of a few `unidentified' IRAS sources 
    Iyengar, K. V. K; Parthasarathy, M (EDP Sciences, 1997-01)
    We selected 33 unidentified IRAS sources based on the following criteria: i) galactic latitude more than 2 deg, ii) have flux density higher than 1 Jy at 12 microns, iii) have good fluxes at 12, 25, and 60 microns with ...
  • Electromagnetic properties of neutral and charged spin-1 particles 
    Nieves, J. F; Pal, P. B (The American Physical Society, 1997-03)
    The structure of the electromagnetic vertex of spin-1 particles is studied in a general way, for the diagonal as well as the off-diagonal couplings. In each case, we consider in detail the consequences of gauge invariance ...
  • Dispersion velocity of Galactic dark matter particles- Reply 
    Cowsik, R; Ratnam, C; Bhattacharjee, P (The American Physical Society, 1997-03)
    A Reply to the Comment by N. W. Evans. Also, Evalyn Gates, Marc Kamionkowski, and Michael S. Turner.
  • The Spectrum of the Cool R Coronae Borealis Variable S Apodis in a Deep Decline 
    Goswami, A; Kameswara Rao, N; Lambert, D. L; Smith, V. V (Astronomical Society of the Pacific, 1997-03)
    A high resolution spectrum (5575 - 8875\AA) of the cool R Coronae Borealis variable S Apodis in its 1993 deep decline is discussed. Narrow or chromospheric emission lines of Na I, K I, Ca II, and Ba II and broad emission ...
  • The solar dynamo with meridional circulation 
    Choudhuri, A. R; Schuessler, M; Dikpati, M (European Southern Observatory, 1997-03)
    In the mathematical form for the coefficient given in the expression (4) in this paper, the value of the parameters d and d should actually be 0.025R/sub0 instead of as printed. We became aware of this typographical error ...
  • Gyroscopic precession and centrifugal force in the Ernst spacetime 
    Rajesh Nayak, K; Vishveshwara, C. V (Springer, 1997-03)
    The phenomenon of gyroscopic precession in the Ernst spacetime is studied within the framework of the Frenet-Serret formalism. General formulae are obtained for circular orbits. At the same time general relativistic analogues ...
  • Detection of Short-Period Coronal Oscillations during the Total Solar Eclipse of 24 October, 1995 
    Singh, J; Cowsik, R; Raveendran, A. V; Bagare, S. P; Saxena, A. K; Sundararaman, K; Krishan, V; Naidu, N; Samson, J. P. A; Gabriel, F (Springer, 1997-02)
    An experiment to search for short-period oscillations in the solar corona was conducted during the total solar eclipse of 1995 October 24 at Kalpi, India. The intensity in the continuum, centred around 5500 Å and with a ...
  • Stellar contents of the open clusters Be 64 and Be 69 
    Pandey, A. K; Durgapal, A. K; Bhatt, B. C; Mohan, V; Mahra, H. S (EDP Sciences, 1997-04)
    We present UBVRI CCD photometry for previously unstudied open clusters (Be 64 and Be 69). Photometry has also been carried out for nearby fields to correct for the effects of field stars contamination. From the colour-colour ...
  • Multicolour deep CCD photometric study of the moderately young southern open star clusters NGC 3228, NGC 4103, NGC 5662 and NGC 6087 
    Sagar, R; Cannon, R. D (EDP Sciences, 1997-04)
    CCD observations in the U, B, V, R and I passbands have been used to generate colour-colour and deep colour-magnitude diagrams for the young open star clusters NGC 3228, NGC 4103, NGC 5662 and NGC 6087. The sample consists ...
  • Galactic Age Estimates from O-rich Stardust in Meteorites 
    Nittler, L. R; Cowsik, R (The American Physical Society, 1997-01)
    The sup16Osup/17 supO and sup16O/sup18O ratios of refractory oxide grains extracted from primitive meteorites suggest that they originated in low-mass red giant stars prior to the formation of the Solar System 4.6×10/sup9 ...
  • Multisite observations of surface structures on AB Doradus in 1994 November 
    Collier Cameron, A; Walter, F. M; Vilhu, O; Böhm, T; Catala, C; Char, S; Clarke, F. J; Felenbok, P; Foing, B. H; Ghosh, K. K; Hao, J; Huang, L; Jackson, D. A; Janot-Pacheco, E; Jiang, S; Lagrange, A. M; Suntzeff, N; Zhai, D. S (The Royal Astronomical Society, 1999-09)
    We present time-resolved optical spectroscopy and broad-band photometry of the rapidly rotating southern K0 dwarf star AB Doradus, obtained during 1994 November. The data were obtained as part of a collaboration dedicated ...
  • General Relativistic Effects on the Ohmic Decay of Crustal Magnetic Fields in Neutron Stars 
    Sengupta, S (The American Astronomical Society, 1997-04)
    The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating the effect of spacetime curvature produced by the intense gravitational field of the star. It is shown that the ...
  • Molecular Line Polarization in the Solar Atmosphere: MGH Lines 
    Mohan Rao, D; Rangarajan, K. E (The American Astronomical Society, 1999-10)
    The polarimetric observations of the quiet Sun show linear polarization in molecular lines of C_2, MgH, etc. The molecular lines are very faint in the intensity spectrum. We propose that the polarization is caused by ...
  • Resonance line polarization in the presence of wave motion 
    Rangarajan, K. E (European Southern Observatory, 1997-04)
    The effect of wave velocity on resonance line polarization is studied. We assumed a photosphere - chromosphere type of temperature structure for the atmosphere with plane parallel symmetry. The "Discrete Space Theory ...
  • Constrained Violent Relaxation to a Spherical Halo 
    Mangalam, A; Nityananda, R; Sridhar, S (The American Astronomical Society, 1999-10)
    Violent relaxation during the collapse of a galaxy halo is known to be incomplete in realistic cases such as cosmological infall or mergers. We adopt a physical picture of strong but short-lived interactions between potential ...
  • The Chromospheric Network - (A) Network Evolution Viewed as a Diffusion Process 
    Srikanth, R; Singh, J; Raju, K. P (Kluwer Academic Publishers, 1999-03)
    Autocorrelation and cross-correlation techniques have been applied to obtain quantitative information about the dynamics of magnetic flux on the solar surface. The speed of network magnetic elements and the diffusion ...
  • The effect of angle-dependent non-coherent electron scattering and partial redistribution on the polarization of resonance lines 
    Rangarajan, K. E (The Royal Astronomical Society, 1999-10)
    The polarized radiative transfer equation is solved when angle-dependent partial redistribution and non-coherent electron scattering are included as line-scattering mechanisms. A static atmosphere with plane parallel ...
  • Abundance Analyses of Field RV Tauri Variables. III. DY Aquilae, SS Geminorum, CT Orionis, and CE Virginis 
    Gonzalez, G; Lambert, D. L; Giridhar, S (The American Astronomical Society, 1997-05)
    Analyses of the photospheric compositions of the four field RV Tauri stars, DY Aql, SS Gem, CT Ori, and CE Vir, indicate that to varying degrees they have experienced fractionation processes that have preferentially depleted ...

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