IIA Institutional Repository: Recent submissions

  • BVRI photometry of the Dipper Asterism region in M 67 
    Anupama, G. C; Kembhavi, A. K; Prabhu, T. P; Singh, K. P; Bhat, P. N (European Southern Observatory, 1995-02)
    We present Cousins BVRI magnitudes for stars in the M 67 `dipper asterism' region, based on observations carried out at the prime focus of the 2.3 m Vainu Bappu Telescope of the Vainu Bappu Observatory, Kavalur. The ...
  • The CA II triplet lines in cool stars 
    Mallik, S. G. V (European Southern Observatory, 1994-02)
    Observations of the infrared triplet lines of ionized calcium are presented for 91 stars brighter than m_v_=+7.0 in the spectral range F8-M4 of all luminosity classes and over a range of metallicities [Fe/H] from -0.65 to ...
  • BV photometry and H-alpha spectroscopy of the RS Canum Venaticorum binary V711 Tauri 
    Mohin, S; Raveendran, A. V (European Southern Observatory, 1993-08)
    Differential BV photometry of V711 Tau obtained on a total of 120 nights during the years 1984-1991 and H-alpha spectroscopy obtained on 14 nights during the 1990-1991 observing season are presented. We find that the mean ...
  • Implications of the Crustal Moment of Inertia for Neutron Star Equations of State 
    Datta, B; Alpar, M. A (European Southern Observatory, 1993-08)
    The dynamical models for neutron star glitches and postglitch behaviour, and the information they yield on the crustal moment of inertia, are applied to a catalogue of neutron star models. The implications for neutron star ...
  • On the Maxwellian alternative to the galactic dark matter problem 
    Sivaram, C (European Southern Observatory, 1993-08)
    Recently a new type of gravitational coupling due to a gravo-inductive force field generated by mass currents was introduced to account for constant rotation velocities at large distances from galactic cores. It is pointed ...
  • Contribution of polarons and bipolarons to low-temperature conductivity in doped polypyrrole 
    Reghu, M; Subramanyam, S. V; Chatterjee, S (American Physical Society, 1991-02)
    The resistivity of polypyrrole films, from 300 to 1.3 K, doped with ClO4 ions at various concentrations to have a different number of polarons and bipolarons, can be better fitted by T-1/3 than T-1/4. The conduction process ...
  • Energy transport to the solar corona by magnetic kink waves 
    Choudhuri, A. R; Dikpati, M; Banerjee, D (American Astronomical Society, 1993-08-20)
    We show that the magnetic kink waves generated by the motions of photospheric footpoints of the coronal flux tubes can supply adequate energy for heating the quiet corona, provided there are occasional rapid motions of ...
  • Polarimetry of Comet P/Halley - Properties of dust 
    Sen, A. K; Deshpande, M. R; Joshi, U. C; Kameswara Rao, N; Raveendran, A. V (European Southern Observatory, 1991-02)
    Comet P/Halley was observed polarimetrically for seven nights in IHW and other continuum filters, during its pre- and postpreihelion passages. These polarimetric observations have been combined with the observations taken ...
  • Maximum acceleration and magnetic field in the early universe 
    Sivaram, C; de Sabbata, Venzo (Kluwer Academic Publishers, 1991-02)
    The maximum acceleration at the Planck epoch is shown to be related to the maximum magnetic field and curvature as well as temperature in that era. Spin-torsion effects at that epoch also lead to same value.
  • Fibre spectroscopy and BV CCD photometry of the southern open cluster NGC 3114 
    Sagar, R; Sharples, Ray M (European Southern Observatory, 1991-04)
    New spectroscopic and photometric observations are presented for a sample of faint stars which extends the color-magnitude diagram of the open cluster NGC 3114 down to V = 16 mag. The distance to the cluster is estimated ...
  • CCD photometry of the distant young open cluster NGC 7510 
    Sagar, R; Griffiths, W. K (Royal Astronomical Society, 1991-06)
    CCD observations in B, V, and I passbands have been used to generate deep V, (B-V), and V,(V-I) color-magnitude diagrams for the open cluster NGC 7510. The sample consists of 592 stars reaching down to V = 21 mag. There ...
  • Interfacial hydromagnetic waves with shear and inclined magnetic fields 
    Satya Narayanan, A; Ramesh, R (Astronomical Society of India, 2002-09)
    The combined effect of non-parallel propagation, steady :flow and inclined magnetic field on the . propagation characteristics of hydromagnetic surface waves is examined. The fluid is assumed to be perfectly conducting ...
  • How Thick are the Saturn's Rings? 
    Chakrabarti, S. K; Bhattacharyya, A (Astronomical Society of India, 2002-09)
    It has been long thought that the rings of saturn are probably not thicker than a few hundreds of meters. By actually following the motion of particles inside the decaying bending waves of the Saturn's rings and matching the ...
  • Can geoeffectiveness of CMEs be predicted? 
    Srivastava, N (Astronomical Society of India, 2002-09)
    Coronal mass ejections or CMEs are well known as the drivers of enhanced interplanetary and geomagnetic activity. They are large expulsions of material from the Sun, which travel into the interplanetary (IP) medium. ...
  • Probing the Sun's hot atmosphere: Views from Yohkoh, SOHO and TRACE 
    Dwivedi, B. N (Astronomical Society of India, 2002-09)
    This article reviews some recent progress in our understanding of the Sun's hot atmosphere. using data from spacecraft (Yohkoh, SOHO and TRACE) and from ground-based eclipse experiments.
  • Dynamics of the Solar Magnetic Network. II. Heating the Magnetized Chromosphere 
    Hasan, S. S; van Ballegooijen, A. A (The American Astronomical Society, 2008-06-20)
    We consider recent observations of the chromospheric network and argue that the bright network grains observed in the Ca ii H and K lines are heated by an as-yet-unidentified quasi-steady process. We propose that the heating ...
  • Intensity oscillations and heating of the coronal X-ray bright points from Hinode/XRT 
    Kariyappa, R; Varghese, B. A (EDP Sciences, 2008-07)
    Aims. Our aim is to investigate the intensity oscillations in coronal X-ray Bright Points (XBPs). Methods. We analysed a 7 h long time sequence of the soft X-ray images obtained on April 14, 2007 with a 2 min cadence using ...
  • Zeeman line formation in solar magnetic fields. Studies with empirical probability distribution functions 
    Sampoorna, M; Nagendra, K. N; Frisch, H; Stenflo, J. O (EDP Sciences, 2008-07)
    Context. Numerical simulations of magneto-convection and analysis of solar magnetograms provide probability distribution functions (PDFs) for the magnetic field strength. Aims. In the paper, we explore the effects of these ...
  • The maximum mass of neutron stars 
    Srinivasan, G (Astronomical Society of India, 2002-09)
    The choice of a suitable topic for this talk posed a problem for me. Should I talk about some work I have done recently? Or, should I talk about something which is not yet resolved, but of great contemporary Significance? ...
  • Stellar Disruption by Supermassive Black Holes and the Quasar Radio Loudness Dichotomy 
    Gopal-Krishna; Mangalam, A; Wiita, P. J (The American Astronomical Society, 2008-06-10)
    The origin of the dichotomy of radio loudness among quasars can be explained using recent findings that the mass of the central supermassive black hole (SMBH) in extended radio-loud quasars is systematically a few times ...

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