IIA Institutional Repository: Recent submissions

  • Effects of rotation on the colours and line indices of stars. I - The Alpha Persei Cluster 
    Rajamohan, R; Mathew, A (Indian Academy Sciences, 1988-06)
    Analysis of the available observational data for the Alpha-Persei cluster members shows that rotation effects on the intermediate-band indices c1 and (u-b) are considerable. In c1, rotation produces a reddening of 0.040 ...
  • Reversals in Bz component of interplanetary magnetic field and equatorial zonal electric field 
    Sastri, J. H (Elsevier, 1988-08)
    Sudden northward turnings of the Bz (North-South) component of the interplanetary magnetic field, IMF, are sometimes associated with anomalous reversals in the equatorial East-West electric field. The electric field reversal ...
  • Consequences of a chromospheric temperature rise on the formation of the H-alpha line in late-type supergiants 
    Mallik, S. G. V; Mallik, D. C. V (Royal Astronomical Society, 1988-08)
    Computations of the H-alpha line profiles were performed in a non-LTE moving chromosphere with temperature rise to simulate the observed H-alpha characteristics in G and K supergiants. The comoving frame radiative transfer ...
  • Segregation of dust and abundance inhomogeneities in globular clusters 
    Bhatt, H. C (Royal Astronomical Society, 1988-08)
    Segregation of dust in globular cluster protoclouds is considered as a possible mechanism for producing the observed heavy element abundance inhomogeneities within globular clusters. Segregation of dust towards the protocloud ...
  • Limits on rotation-induced characteristics of radiation from stable rapidly rotating neutron stars 
    Datta, B; Kapoor, R. C (The American Astronomical Society, 1988-08)
    Results are presented of a study of frequency shifts in radiation from the surface of rapidly rotating neutron stars and rotation-induced spectral line broadening as a function of their mass. It is found that, despite large ...
  • Energy transport in intense flux tubes on the sun. I - Equilibrium atmosphere 
    Hasan, S. S (The American Astronomical Society, 1988-09)
    Model calculations are performed to determine self-consistently the equilibrium atmosphere in an intense flux tube. The generalization of the Eddington approximation to three dimensions is used to develop a zeroth-order ...
  • IUE observations of high galactic latitude F supergiants HD 161796 and HD 187885 
    Parthasarathy, M; Pottasch, S. R; Wamsteker, W (European Southern Observatory, 1988-09)
    Low resolution (6 A) IUE ultraviolet spectra of the high galactic latitude F supergiants HD 161796 (F3 Ib) and HD 187885 (F2-3I) are analyzed. The UV spectrum (1250 A to 3250 A) of HD 161796 shows no excess UV flux ...
  • Lines Formed in Slowly Expanding Thin Spherical Shell 
    Peraiah, A; Raghunath, G; Nagendra, K. N (Indian Institute of Astrophysics, Bangalore, 1980)
    We have investigated how an optically thin spherical shell with small velocities change the profiles and equivalent widths of the lines. We have employed several types of variations in density, velocity of expansion and ...
  • Astrometry from mutual events of Jovian satellites in 1997 
    Vasundhara, R; Arlot, J. E; Lainey, V; Thuillot, W (The European Southern Observatory, 2003-10)
    Astrometric results of observations of the mutual events of the Galilean satellites of Jupiter of the PHEMU97 campaign by the Institut de Mécanique Céleste et de Calcul des Éphémérides are presented. These astrometric ...
  • A High-Resolution Spectrum of the R Coronae Borealis Star V2552 Ophiuchi 
    Kameswara Rao, N; Lambert, D. L (The Astronomical Society of the Pacific, 2003-11)
    Photometry and low-resolution spectroscopy have added V2552 Oph to the rare class of R Coronae Borealis variables. We confirm this classification of V2552 Oph through a comparison of our high-resolution optical spectrum ...
  • Metric Radio Observations of the Evolution of a ``Halo'' Coronal Mass Ejection Close to the Sun 
    Ramesh, R; Kathiravan, C; Sastry, Ch. V (The American Astronomical Society, 2003-07-10)
    We report direct imaging observations of the propagation of a diffuse thermal radio enhancement in close temporal and spatial association with a ``halo'' coronal mass ejection from the solar atmosphere, in the metric ...
  • UV(IUE) spectra of hot post-AGB candidates 
    Gauba, G; Parthasarathy, M (The European Southern Observatory, 2003-09)
    Analysis of the low resolution UV(IUE) spectra (1150 to 3200 Å) of 15 hot post-AGB candidates is presented. The UV(IUE) spectra of 10 stars suggest partial obscuration of the hot stars due to circumstellar dust. The reddened ...
  • The proton synchrotron model of TeV gamma ray bursts and their detectability by AMANDA/ICECUBE type detectors 
    Bhattacharjee, P; Gupta, N (Elsevier, 2003-11)
    The detectability of a possible ``high'' energy (>100 GeV) component of gamma ray bursts (GRBs) using AMANDA/ICECUBE large area muon detectors is examined within the context of a specific model of such high energy gamma ...
  • HD 34700: A new T Tauri double-lined spectroscopic binary 
    Arellano, F. A; Giridhar, S (The European Southern Observatory, 2003-09)
    We find the star HD 34700 to be a double-lined spectroscopic binary. We also identify it as a weak-line T Tauri object. The spectra of both components are very similar and both show the Li I feature at 6708 Å. Strong ...
  • The flares associated with the abnormal rotation rates of the bipolar sunspots: Reconnection probably below the surface 
    Hiremath, K. M; Suryanarayana, G. S (The European Southern Observatory, 2003-12)
    We use the observations of Kodaikanal observatory white light pictures to study the association between the rotation rates of the bipolar sunspots and triggering of the flares. For the years 1969-1974, we compute daily ...
  • Large Magellanic Cloud Bar: Evidence of a Warped Bar 
    Subramaniam, A (The European Southern Observatory, 2003-11)
    The geometry of the LMC bar is studied using the dereddened mean magnitudes of the red clump stars (I0) from the Optical Gravitational Lensing Experiment II catalog. The value of I0 is found to vary in the east-west direction ...
  • The optical afterglow of the not so dark GRB 021211 
    Pandey, S. B; Anupama, G. C; Sagar, R; Bhattacharya, D; Castro-Tirado, A. J; Sahu, D. K; Parihar, P. S; Prabhu, T. P (The European Southern Observatory, 2003-09)
    We determine Johnson B,V and Cousins R,I photometric CCD magnitudes for the afterglow of GRB 021211 during the first night after the GRB trigger. The afterglow was very faint and would have been probably missed if no prompt ...
  • Kerr Black Hole in the Background of the Einstein Universe 
    Ramachandra, B. S; Rajesh Nayak, K; Vishveshwara, C. V (Springer, 2003-11)
    The Vaidya-Einstein-Kerr (VEK) black hole which represents the spacetime of the Kerr black hole in a non-vacuum, asymptotically non-flat background is investigated. The energy-momentum tensor corresponding to this spacetime ...
  • Magnetic Field Geometry in `Red' and `Blue' BL Lacs 
    Kharb, P; Gabuzda, D. C; Shastri, P (Springer, 2003-10)
    We compare the systematics of the magnetic field geometry in the `red' low-energy peaked BL Lacs (LBLs) and `blue' high-energy peaked BL Lacs (HBLs) using VLBI polarimetric images. The LBLs are primarily `radio-selected' ...
  • Tidal disruption model for the interacting pair of galaxies VV 117 (NGC 2444/45) 
    Narasimhan, K. S. V. S; Namboodiri, P. M. S; Alladin, S. M (Springer, 2003-09)
    A series of N-body simulations have been performed to interpret the interacting pair of galaxies VV 117 (NGC 2444/45). The galaxies have been modelled assuming a mass ratio two. The simulations use various values for the ...

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