IIA Institutional Repository

Browsing by Subject "Helium"

Browsing by Subject "Helium"

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  • The chemical composition of algol systems. III - Beta Lyrae-nucleosynthesis revealed 
    Balachandran, S; Lambert, D. L; Tomkin, J; Parthasarathy, M (Royal Astronomical Society, 1986-04)
    The B8 primary of the eclipsing binary star Beta Lyr is subjected to high S/N ratio Reticon observations of the visible and near-IR lines of He, C, N, O, Ne, and Fe, in order to determine their abundances. N is noted to ...
  • Expanding shell and P Cygni profiles of 27 Canis Majoris 
    Ghosh, K. K (American Astronomical Society, 1990-09)
    H-alpha and He I profiles of 27 CMa obtained between January 1985 and February 1989 are presented. Velocities of blue absorption and red emission components of H-alpha were different from that of He I, suggesting that the ...
  • Helium abundance in the solar envelope 
    Basu, S (Astronomical Society of India, 2000)
  • The hot R Coronae Borealis star DY Centauri: Nebular and photospheric lines 
    Kameswara Rao, N; Giridhar, S; Lambert, D. L (The European Southern Observatory, 1993-12)
    High resolution spectra in the red region of the hot R CrB star DY Cen show the following characteristics: a strong absorption line spectrum dominated by lines of C II, N II, and Ne I inverse P-Cygni type profiles of some ...
  • Polarimetric observations of hydrogen deficient stars 
    Raveendran, A. V; Kameswara Rao, N; Deshpande, M. R; Joshi, U. C; Kulshrestha, A. K (Reidel Publishing Company, 1986)
    Polarimetric observations of HD 30353, SU Tau, XX Cam, R CrB, UV Cas, BD +13°3224, BD +10°2179 and HD 124448 are presented. The linear polarization of HD 30353 is found to vary appreciably at Hα over a time scale as short ...
  • Spatio-temporal fluctuations in He I 10830 A line parameters - Evidence for spicule formation 
    Venkatakrishnan, P; Jain, S. K; Singh, J; Recely, F; Livingston, W. C (Springer Netherlands, 1992-03)
    The equivalent width, line depth, line width, and Doppler shift of the He i 10830 Å line were extracted from two time series of spectra. Scatter plots of time-averaged line depth, line width, and Doppler shifts, as well ...
  • Spectrophotometric studies of CO Cephei 
    Shylaja, B. S (Indian Academy of Sciences, 1986-09)
    Spectrophotometric and spectroscopic observations of CQ Cep, the shortest-period binary with a WN component, are presented. Excepting the N V 4603 A, the fluxes of all other emission lines show enhancement at minima. They ...
  • A spectroscopic study of the Scorpio-Centaurus association 
    Rajamohan, R (Indian Academy of Sciences, 1976-09)
    Rotational velocities for 112 members of the Scorpio-Centaurus association brighter than 8.5 magnitudes are derived from spectra obtained with a dispersion of 47 A/mm. Hydrogen and helium line intensities are determined ...
  • The synthesis of Al-26 during combined hydrogen and helium-burning reactions 
    Goswami, A; Ramadurai, S; Duorah, H. L (Springer Netherlands, 1992-02)
    The synthesis of Al-26 during combined hydrogen and helium-burning processes in high temperature and density conditions is studied. The possible sites for these processes are believed to be the neutron star surfaces where ...
  • Time variability of the He I 10830 A line profile 
    Singh, J; Jain, S. K; Venkatakrishnan, P (Springer, 1994-03)
    We have studied the time-dependent behavior of the He I 10830 A line. These studies show that (1) the fluctuations of the line width are uncorrelated with the equivalent-width fluctuations and (2) the autocorrelation curves ...
  • 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. ...
  • The variation of the 5200 feature in HD 34452 
    Shylaja, B. S; Babu, G. S. D (Royal Astronomical Society, 1986-10)
    Spectrophotometric observations of the hot Si star HD 34452 = HR 1732 obtained over a duration of four years, from 1979 to 1983, are presented. The period of variation in the broad-band feature centred around λ5200 is found ...
  • Yields of nucleosynthesis from massive and intermediate mass stars and constraints on their final evolution 
    Mallik, D. C. V; Mallik, S. G. V (Indian Academy of Sciences, 1985-09)
    Nucleosynthetic yields and production rates of He and heavy elements are derived using recent revisions in O star counts and the stellar models of Maeder (1981). The current production rates and yields are significantly ...

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