IIAP Publications: Recent submissions

  • CCD photometry in VRI bands of the galactic cluster NGC 2818 
    Surendiranath, R; Kameswara Rao, N; Sagar, R; Nathan, J. S; Ghosh, K. K (Indian Academy of Sciences, 1990-06)
    The open cluster NGC 2818 containing a planetary nebula has been observed in VRI bands using the CCD system at prime focus of the 2.3 meter Vainu Bappu Telescope. The study extending to stars V of 21 magnitude established ...
  • Radiative transfer with Compton scattering in plane parallel geometry 
    Peraiah, A (Indian Academy of Sciences, 1990-06)
    The equation of radiative transfer with Compton scattering is solved. The specific intensity has been expanded by Taylor series with respect to wavelength and the first three terms have been retained in solving the transfer ...
  • Evolution of latitude zonal structure of the large-scale magnetic field in solar cycles 
    Makarov, V. I; Sivaraman, K. R (Springer, 1989-03)
    The latitude zonal component of the large-scale solar magnetic field is analyzed using H-alpha charts for the 1905-1982 period, and the poleward migration of prominences is used to calculate the time of reversal of the ...
  • The UV spectrum of the WC 11 star CPD -56 deg 8032 
    Kameswara Rao, N; Giridhar, S; Nandy, K (The European Southern Observatory, 1990-08)
    UV observations of the WC 11 central star of the compact planetary nebula CPD -56 deg 8032 show that the continuum flux is variable. This variability appears to be caused by a change in the circumstellar extinction properties. ...
  • Analysis of Ca(+) K plage area for short period variation 
    Singh, J; Jain, S. K (Indian Academy of Sciences, 1989-12)
    Observations of solar Ca(+) K daily plage area from 1951 to 1977 are analyzed to search for short-period (12-13 day) variations. The 27-day periodicity due to solar rotation modulation is found at all latitudes. Using an ...
  • A photometric study of F-type stars of high galactic latitude 
    Ferro, A. A; Giridhar, S; Chavez, M; Parrao, L (European Southern Observatory, 1989-04)
    Photometry in the O I 7774 A line and the uvbybeta system is presented for a group of high Galactic latitude F-type luminosity type I stars. The results indicate that the candidates are high gravity near solar Fe/H abundance ...
  • CCD photometry of the distant southern globular cluster NGC 5824 
    Cannon, R. D; Sagar, R; Hawkins, M. R. S (Royal Astronomical Society, 1990-03)
    A V, (B-V) C-M diagram for the distant globular cluster NGC 5824 is obtained from CCD observations of 285 stars reaching V = 20.5. Assuming a reddening of E(B-V) = 0.13, the color of the giant branch at the level of the ...
  • The ultraviolet spectrum of the hydrogen-poor binary HD 30353 
    Parthasarathy, M; Hack, M; Tektunali, G (The European Southern Observatory, 1990-04)
    An analysis is made of the high- and low-resolution UV spectra of the hydrogen-poor star HD 30353. The stellar wind profiles of the resonance lines of N V, C V, and Si IV are found to be similar to those observed in Upsilon ...
  • Second National Workshop on Solar Physics, Indian Institute of Astrophysics, Kodaikanal, India 
    Krishan, V; Sastry, Ch. V (Springer, 1989-09)
    This paper a brief report about the topics discussed at the second Indian national Workshop on Solar Physics held in September 1987
  • Supernova SN 1987A - Rotation rate of the central pulsar 
    Bhatt, H. C; Datta, B (Royal Astronomical Society, 1989-04)
    Using available observational data on supernova SN 1987A, firm quantitative lower limits on the rotation period of the central pulsar (assuming the pulsar luminosity to power the supernova light curve) are derived. It is ...
  • Occultations by possible material in Saturn's outer magnetosphere. II 
    Vasundhara, R (Indian Academy of Sciences, 1989-03)
    Results of a search for occultations of stars in the SAO catalog by Saturn's outer magnetosphere during 1989-1990 are presented. A total of nine events are predicted to occur during this period. The most favorable event ...
  • Tidal change in the energy of a spherical galaxy 
    Namboodiri, P. M. S; Kochhar, R. K (Royal Astronomical Society, 1990-03)
    Tidal effects of a massive perturber on a satellite galaxy have been studied by numerical simulations. The model consists of a spherical satellite galaxy and a point-mass perturber and the encounter is non-penetrating. A ...
  • An internally consistent set of oscillator strengths for Fe I lines 
    Giridhar, S; Ferro, A. A (Indian Academy of Sciences, 1989-03)
    An extensive set of internally consistent oscillator strength values for Fe I lines is compiled using literature data and scaling the oscillator strengths derived by different workers to that of Blackwell and his coworkers. ...
  • Sunspot activity as originating in interference of the sun's global MHD oscillations 
    Gokhale, M. H; Javaraiah, J (Royal Astronomical Society, 1990-03)
    Spherical-harmonic-Fourier (SHF) analysis of sunspot activity during 1902-54 show that the sunspot occurrence probability p(theta, phi, t) is given by superposition of, mainly, axisymmetric even degree SHF modes of l not ...
  • Tidal transfer of energy and angular momentum to spheroidal galaxies 
    Som Sunder, G; Kochhar, R. K; Alladin, S. M (Royal Astronomical Society, 1990-06)
    The tidal transfer of energy and angular momentum to a spheriodal test galaxy is studied using tensor virial equations within the framework of impulse approximation. The tidally introduced angular momentum is always along ...
  • Integrated parameters of open clusters 
    Pandey, A. K; Bhatt, B. C; Mahra, H. S; Sagar, R (Royal Astronomical Society, 1989-01)
    Integrated magnitudes and colors of population I synthetic clusters have been derived using theoretical evolutionary tracks and an age-dependednt initial mass function. A comparison of the theoretically obtained integrated ...
  • Stability of cool flux tubes in the solar chromosphere. II - Non-linear dynamical behaviour 
    Hasan, S. S; Kneer, F (The European Southern Observatory, 1990-06)
    A single vertical cool flux tube in the solar chromosphere is focused upon for stability studies. The analysis of a previous study by Hasan and Kneer (1986) is extended to the nonlinear regime with a view to examining the ...
  • Comments on the variability and physical parameters of the F supergiant Phi Cassiopeiae 
    Ferro, A. A; Parrao, L; Giridhar, S (Astronomical Society of the Pacific, 1988-08)
    UBVRI and uvby photometry and radial velocities have been obtained for the F0 Ia supergiant Phi Cas. The variability is confirmed from the radial velocities; the velocity range is small (Delta V/subr of about 6 km/s). No ...
  • Radial distribution of the integrated light and photometric colours in open star clusters 
    Sagar, R; Bhatt, H. C (Indian Academy of Sciences, 1989-06)
    Mass segregation in the form of preferential concentration of more massive stars in the central regions of a number of open star clusters has been known for some time. In this paper, integrated UBV colors in concentric ...
  • Is the X-ray pulsar H 0253 + 193 a neutron star spun down in a molecular cloud? 
    Bhatt, H. C (The European Southern Observatory, 1990-06)
    The detection of 206s X-ray pulsations from H0253+193 indicates that the source is a compact object. It is argued here that object can not be a T Tauri star or Be/X –ray binary pulsar suggested that H 0253+193 is slowly ...

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