IIAP Publications: Recent submissions

  • A deep UBVRI CCD photometric study of the open clusters Tr1 and Be 11 
    Yadav, R. K. S; Sagar, R (Royal Astronomical Society, 2002-11)
    We present deep UBVRI charge-coupled device (CCD) photometry for the young open star clusters Tr1 and Be11. The CCD data for Be11 are obtained for the first time. The sample consists of ~1500 stars reaching down to V~ 21 ...
  • Nature of Tilt Angles of Sunspot Groups During the 22nd Solar Cycle 
    Muneer, S; Singh, J (Springer, 2002-10)
    Daily white-light images from Kodaikanal Observatory have been utilized to study the nature of tilt angles of sunspot groups during the 22nd solar cycle. 2416 spot groups have been measured to find the tilt angle. An average ...
  • Imaging With The Mauritius Radio Telescope Challenges and Results 
    Udaya Shankar, N; Golap, K; Sachdev, S; Dodson, R; Katwaroo, M; Sastry, Ch. V (Springer, 2002)
    The Mauritius Radio Telescope (MRT) has been built with the main objective of surveying the southern sky at meter wavelengths. MRT is a Fourier synthesis, T-shaped non-coplanar array. It consists of a2048 m long East-West ...
  • The Mass Function of Young Star Clusters in our Galaxy and Nearby Galaxies: Is It Universal? 
    Sagar, R (International Astronomical union, 2002)
    Mass functions (MFs) derived from photometric observations of young star clusters of our Galaxy, the Magellanic Clouds (MCs), M31 and M33 have been used to investigate the question of universality of the initial mass ...
  • Spectroscopic Observation of Coronal Waves 
    Sakurai, T; Ichimoto, K; Raju, K. P; Singh, J (Springer, 2002-10)
    A time sequence over 80 min of coronal green-line spectra was obtained with a corona- graph at the Norikura Solar Observatory. Doppler velocities, line intensities, and line widths were derived through fitting a single ...
  • On the Out of Phase Appearance of Large-Scale Diffuse Magnetic Field of the Sun with Respect to Sunspots 
    Dikpati, M; Choudhuri, A. R (Kluwer Academic Publishers, 1996-03)
    We assume the large-scale diffuse magnetic field of the Sun to originate from the poloidal component of a dynamo operating at the base of the convection zone, whereas the sunspots are due to the toroidal component. The ...
  • Estimation of Fried's Parameter From Specklegrams of Solar Features 
    Sridharan, R; Venkatakrishnan, P; Verma, V. K (Springer, 2002-12)
    A few methods of estimating Fried's parameter (r 0) from specklegrams of solar features are described. Some of these methods were used to estimate r 0 for the speckle data obtained from Kodaikanal Observatory (KO), Uttar ...
  • Dynamical Effects in Solar Photospheric Flux Tubes 
    Hasan, S. S (Kluwer Academic Publisher, 1996)
    The interaction of an intense flux tube, extending vertically through the photosphere, with p-modes in the ambient medium is modelled by solving the time dependent MHD equations in the thin flux tube approximation. It is ...
  • Observability of Coronal Heating Processes 
    Venkatakrishnan, P (Kluwer Academic Publishers, 1996)
    The mechanisms that could possibly heat the corona are briefly reviewed with emphasis on their observability. Observing enhanced wave flux at footpoints of active regions would confirm wave heating. Observation of nonthermal ...
  • A Near Infrared Photometric Study of the Young Orion Nebula Star Cluster NGC 1976 
    Qian, Z. Y; Sagar, R (Royal Astronomical Society, 1994-01)
    We have measured the JHK magnitudes of 47 stars in the region of the extremely young Orion nebula star cluster NGC 1976. These, in combination with the existing near-infrared and optical data, are used to study the ...
  • Mutual phenomena of the Galilean satellites: an analysis of the 1991 observations from VBO 
    Vasundhara, R (European Southern Observatory, 1994-01)
    Results of analysis of seventeen mutual events, of the Galilean satellites, observed at the Vainu Bappu Observatory (VBO) during the 1991 are presented. The light curves were fitted with theoretical models to derive the ...
  • 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.

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