IIA Institutional Repository: Recent submissions

  • Neutrino induced nucleosynthesis 
    Ramadurai, S; Schramm, D. N (Astronomical Society of India, 1993)
    The detection of neutrinos from SN1987a has revived the interest in neutrino induced nucleosynthesis. In this work various results on the neutrino produced abundances of several isotopes are summarized and compared with ...
  • A search for TeV photons from 4U0115 + 63 
    Rannot, R. C; Bhat, C. L; Senecha, V. K; Sapru, M. L; Tickoo, A. K; Kaul, R. K; Rawat, H. S (Astronomical Society of India, 1993)
    An analysis of 47 hours of data collected by the Gulmarg gamma-ray telescope during the period 1989 September 27-October 30, indicates absence of a statistically significant steady, persistent-pulsed or episodic pulsed ...
  • Near infrared coronal line emission in nova Herculis 1991 
    Chandrasekhar, T; Ashok, N. M; Ragland, S (Astronomical Society of India, 1993)
    Near infrared coronal line emission at 1.98 +/- 0.02 micrometers due to (Si VI) detected in the spectrum of Nova Herculis 1991 as early as about 17 days after optical maximum is reported. The coronal line observations ...
  • Detached cold dust shells around yellow variable supergiants TW Aql, AI CMi, V 925 SCO and related stars 
    Parthasarathy, M; Reddy, B. E (Astronomical Society of India, 1993)
    TW Azl, AI CMi, V 924 Sco, ST Pup, AX Sgr, AD Aql, V1027 Cyg are yellow variable supergiants. We find these stars to be far-infrared (IRAS) sources with flux maximum around 25 micrometers. Analysis of the IRAS fluxes shows ...
  • Terrestrial effects of PSR 0950 + 08 (Paper 2) 
    Vats, Hari Om; Chandra, H; Deshpande, M. R; Janardhan, P; Vyas, G. D (Astronomical Society of India, 1993)
    This article presents indirect evidence that on July 29, 1992 PSR 0950 + 08 emitted a burst of X-ray emissions along with the enhanced radio pulses. This indirect evidence is seen in the form of excess absorption of HF ...
  • Observations of PSR 0950 + 08 at 103 MHz 
    Deshpande, M. R; Vats, Hari Om; Janardhan, P; Bobra, A. D (Astronomical Society of India, 1993)
    n this article we report the possible cause of an enormously large enhancement (burst) in the ratio flux of PSR 0950 + 08. The burst was observed by two radio telescopes at Rajkot and Thaltej separated by 20 km. Simple ...
  • Post-AGB A-F supergiant stars 
    Parthasarathy, M; Reddy, B. E (Astronomical Society of India, 1993)
    We have searched the IRAS Polar Stratospheric Clouds (PSC) for dust shells around A-F supergiant stars similar to the high galactic latitude A-F supergiants with circumstellar dust shells. We have found that HD 114855 ...
  • Spectroscopy of IRAS sources with far IR colors similar to those of planetary nebulae 
    Reddy, B. E; Parthasarathy, M (Astronomical Society of India, 1993)
    Optical candidates of 17 unidentified IRAS sources with far-infrared colors similar to planetary nebulae have been detected on sky survey plates. Low resolution CCD spectra of seven optical candidates suggests that they ...
  • Photometric elements, absolute dimensions and evolutionary status of the eclipsing binary HU Tauri 
    Parthasarathy, M; Sarma, M. B. K; Vivekananda Rao, P (Astronomical Society of India, 1993)
    The photometric elements of HU Tauri are derived from an analysis of its B and V light curve using the Wilson and Devinney (1971) light curve synthesis method. The photometric elements suggest that HU Tauri is a semi-detached ...
  • Mass transfer in ALGOLS and its implications to the mass transfer theory 
    Chaubey, U. S (Astronomical Society of India, 1993)
    he average mass transfer rates in four Algol-type binary stars RZ Cas, TV Cas, SW Cyg and DI Peg are derived from their observed period changes in the light of alternate period change model. The results have been used to ...
  • Near infrared photometry of unassociated IRAS point sources in the zodiacal belt 
    Ashok, N. M; Chandrasekhar, T; Ragland, S; Watson, P. V (Astronomical Society of India, 1993)
    An observational program to generate a list of bright near infrared sources using IRAS Point Source Catalogue for further studies using lunar occultation technique has been initiated at Physical Research Laboratory, ...
  • Interstellar grains in the regions of anomalous extinction 
    Vaidya, D. B; Anandarao, B. G (Astronomical Society of India, 1993)
    We have evaluated the interstellar extinction curve and the ratio R of the total to the selective extinction using exact computations of extinction efficiencies for various grain models. The computed results are compared ...
  • Balloon-borne far-infrared mapping of galactic star forming regions 
    Das, B; Ghosh, S. K; Rengarajan, T. N; Verma, R. P; Iyengar, K. V. K; Tandon, S. N (Astronomical Society of India, 1993)
    Large angular areas (greater than 500 sq arcmin each) covering the three Galactic star forming regions (NGC 2024, OMC-1/OMC-2, and IRAS 06058 + 2138 and its neighborhood) have been mapped in two FIR bands (58 and 150 ...
  • The infall time-scale in the solar neighborhood 
    Basu, S (Astronomical Society of India, 1993)
    The Galactic disk is supposed to have been formed from gas condensing out from the halo. The rate at which this infall of gas occurs, the amount of infall, and the time scales over which gas falls on to the disc have ...
  • Effects of velocity laws on line formation 
    Srinivasa Rao, M; Varghese, B. A (Astronomical Society of India, 1993)
    We calculated the spectral line profiles in a spherically symmetric expanding medium. Complete redistribution of photons in the line for a two level atom is assumed with Doppler profile function in a purely scattering ...
  • Dwarf cepheid DY Pegasus -- revisited 
    Kilambi, G. C; Rahman, A (Astronomical Society of India, 1993)
    UBV broadband photoelectric photometry of dwarf cepheid DY Pegasus is presented. Using the observed light variations of this pulsating variable, mass, radius, gravity and temperature variations over a pulsational cycle ...
  • Velocity field structure in the Orion Nebula 
    Seema, P; Banerjee, D. P. K; Anandarao, B. G (Astronomical Society of India, 1993)
    High quality interferograms have been obtained on the H II region in the Orion Nebula in the emission line of (OIII) 5007 A using the high resolution imaging Fabry-Perot spectrometer. Velocity profiles were obtained for ...
  • Intracluster extinction in young open star clusters 
    Sagar, R; Qian, Z. Y (Astronomical Society of India, 1993)
    An analysis of near-infrared data in combination with optical observations, indicates a normal interstellar extinction law around hot O and B stars at wavelengths greater than or = 0.9 micrometers. At shorter wavelengths, ...
  • Ultra rapid variability in gamma CAS and lambda ERI 
    Chakraborty, A; Anandarao, B. G; Swaminathan, R (Astronomical Society of India, 1993)
    We present here preliminary results of observations on two Be stars gamma Cas and lambda Eri made during 27-30 December 1992 and 14-15 February 1993.
  • Hard X-ray spectra of some X-ray binaries from balloon-borne observations 
    Chitnis, V. R; Agrawal, P. C; Manchanda, R. K; Rao, A. R (Astronomical Society of India, 1993)
    We have studied X-ray binaries 4U1907 + 09, GX1 + 4 and Cygnus X-1 in the energy range 20-100 keV, using balloon-borne xenon-filled multilayer proportional counters flown from Hyderabad, India. Results of these observations ...

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