IIA Institutional Repository: Recent submissions

  • Magnetic fields in the sun's interior: What do we know about them? 
    Choudhuri, A. R (Astronomical Society of India, 1996)
    The surface observations of the solar magnetic fields put some constraints on the possible magnetic configurations in the Sun's interior. It is currently believed that the solar magnetic fields are generated by a dynamo ...
  • The influence of chromospheric magnetism on oscillation frequencies 
    Roberts, B (Astronomical Society of India, 1996)
    The influence of chromospheric magnetism on p- and f-modes is examined. The magnetism is modelled as a horizontal canopy field, embedded in an isothermal atmosphere, overlying a field-free polytropic convection zone. Both ...
  • BiSON observations, their application to the rotation of the solar interior and to excitation mechanisms - the advantages of long, continuous time series 
    Elsworth, Y (Astronomical Society of India, 1996)
    The Birmingham Solar Oscillations group runs the so-called BiSON network. As the network has been operational since 1981 we have the great advantage of long, well-filled, historical datasets. These data have been put to ...
  • Elemental abundance survey of the galactic thick disc 
    Reddy, B. E; Lambert, D. L; Prieto, Carlos Allende (Blackwell Publishing, 2006-04)
    We have performed an abundance analysis for F- and G- dwarfs of the Galactic thick-disc component. A sample of 176 nearby (d≤ 150 pc) thick-disc candidate stars was chosen from the Hipparcos catalogue and subjected to a ...
  • Using solar oscillations to constrain the equation of state and low-temperature opacities 
    Guzik, J. A; Cox, A. N; Swenson, F. J (Astronomical Society of India, 1996)
    Because thousands of solar p-mode oscillation frequencies have been measured to high accuracy, direct comparisons between calculated and observed frequencies are an excellent means of testing solar interior physics. Here ...
  • Helioseismic diagnosis of the equation of state 
    Dappen, W (Astronomical Society of India, 1996)
    The helioseismic verification of major nonideal effects in the equation of state of solar matter has become well established. The dominant contribution is the Coulomb pressure, conventionally described in the Debye-Huckel ...
  • Solar structure as revealed by 1 year LOWL data 
    Basu, S; Christensen-Dalsgaard, J; Schou, J; Thompson, M. J; Tomczyk, S (Astronomical Society of India, 1996)
    We have used solar frequencies obtained form 1 year of observations with LOWL instrument to investigate the radial stratification of the Sun. Models which include the diffusion of helium and heavy elements below the solar ...
  • Solar neutrino flux variation and its implications 
    Raychaudhuri, Probhas (Astronomical Society of India, 1996)
    Considering the solar neutrino flux data during the period from June 1989 to April 1992 from four solar neutrino experiments (Cl Solar neutrino experiment, SAGE I & II, GALLEX, Kamiokande II & III) we suggest that the ...
  • Seismic probing of the solar core 
    Dziembowski, W. A (Astronomical Society of India, 1996)
    Only a small fraction of the solar p-modes have frequencies with any measurable sensitivity to the core structure. Nevertheless an accurate seismic sounding with such modes alone is possible. This requires a high-precision ...
  • Near-infrared and optical studies of the fast nova V4643 Sgr (Nova Sagittarii 2001) 
    Ashok, N. M; Banerjee, D. P. K; Varricatt, W. P; Kamath, U. S (Blackwell Publishing, 2006-05)
    V4643 Sagittarii or Nova Sagittarii 2001 was discovered in outburst at 7.7 mag on 2001 February 24. Here, we present near-infrared results of this fast classical nova obtained in the early decline phase in 2001 March ...
  • Effects on solar structure of opacity changes 
    Tripathy, S. C; Christensen-Dalsgaard, J (Astronomical Society of India, 1996)
    We investigate the sensitivity of solar structure to localized changes in opacity by considering differences between models computed with locally modified opacity and unmodified references models. The results confirm that ...
  • Magnetoacoustic wave propagation in off-limb polar regions 
    O'Shea, E; Banerjee, D; Doyle, J. G (EDP Sciences, 2006-02)
    Aims.To find evidence of magnetoacoustic waves in off-limb polar regions. Methods.Using temporal series data from the Coronal Diagnostic Spectrometer (CDS) on SOHO, we study oscillations found in radiant flux and velocity ...
  • The effect of p-modes on thin magnetic flux tubes 
    Hasan, S. S; Bogdan, T. J (Astronomical Society of India, 1996)
    We examine the effect of p-modes impinging on thin magnetic flux tubes. The aim of the study is to see whether global p-modes can excite wave motions of significant amplitude in a magnetic flux tube. For simplicity we treat ...
  • Transition region counterpart of a moving magnetic feature 
    Lin, C. -H; Banerjee, D; O'Shea, E; Doyle, J. G (EDP Sciences, 2006-12)
    this which we seek to address in this work. Aims.In this work we aim to investigate the chromospheric and transition-region dynamics associated with a moving magnetic monopole by using spectral time-series and ...
  • MHD window on the sun 
    Gokhale, M. H (Astronomical Society of India, 1996)
    Our recent studies of rotation and magnetic field near the Sun's surface have indicated that the solar activity may be originating in interference of global torsional MHD oscillations in the Sun. Using theory of dynamics ...
  • Japanese radio astronomy - Past, present, and future. 
    Deguchi, S (Astronomical Society of India, 1995)
    The past, present and future of radio astronomy in Japan are described form the author's personal view point. The radio astronomy in Japan is quickly growing in terms of the telescope size, the budget scale, and the total ...
  • Li Abundance Survey in Galactic Thin Disk 
    Lambert, D. L; Reddy, B. E (Astronomical Society of the Pacific, 2005-09)
    Lithium abundances for a sample of 451 F and G dwarfs including 181 new stars all belonging to the Galactic thin disk are discussed. Lithium abundances, metallicities ([Fe/H]), masses, and ages are determined (Lambert & ...
  • GRB 051028: an intrinsically faint gamma-ray burst at high redshift? 
    Castro-Tirado, A. J; Jelínek, M; Pandey, S. B; McBreen, S; de Jong, J; Sahu, D. K; Ferrero, P; Caballero, J. A; Gorosabel, J; Kann, D. A; Klose, S; de Ugarte Postigo, A; Anupama, G. C; Gry, C; Guziy, S; Srividya, S; Valdivielso, L; Vanniarajan, S; Henden, A. A (EDP Sciences, 2006-12)
    We present multiwavelength observations of the gamma-ray burst GRB 051028 detected by HETE-2 in order to derive its afterglow emission parameters and to determine the reason for its optical faintness when compared to other ...
  • Non-conservative Rayleigh scattering in a finite atmosphere - II. Polarization in telluric lines 
    Mohan Rao, D; Rangarajan, K. E; Abhyankar, K. D (Astronomical Society of India, 1995)
    We consider non-conservative Rayleigh scattering in finite atmospheres and study the polarization in the molecular lines both in the transmitted and reflected sunlight. We first investigate the parameterized models to ...
  • The discovery of fluorine in cool extreme helium stars 
    Pandey, G (The University of Chicago Press, 2006-08-21)
    Neutral fluorine (F I) lines are identified in the optical spectra of cool extreme helium (EHe) stars. These are the first F I lines identified in a star's spectrum, and they provide the first measurement of fluorine ...

Search DSpace

Browse

My Account