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Browsing by Subject "Stellar Envelopes"

Browsing by Subject "Stellar Envelopes"

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  • Capture of field stars by molecular clouds 
    Bhatt, H. C (European Southern Observatory, 1989-04)
    Field stars can be captured by massive interstellar clouds. Stars encounter interstellar clouds with relative velocities that have a distribution. Close encounters in which stars enter a cloud with relative velocities less ...
  • 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 ...
  • The far-infrared (IRAS) excess in HD 161796 and related stars 
    Parthasarathy, M; Pottasch, S. R (European Southern Observatory, 1986-01)
    The far infrared IRAS measurements of the high galactic latitude F-supergiant HD 161796 and related stars are found to show strong far infrared excesses, due to large amounts of dust around them. For HD 161796 the dust ...
  • Observations of hydrogen deficient binary Upsilon Sagittarii 
    Kameswara Rao, N; Venugopal, V. R (Indian Academy of Sciences, 1985-06)
    The absolute magnitude M(v) of the hydrogen deficient binary Upsilon Sgr has been estimated as -4.8 + or - 1.0 from the distribution of the interstellar reddening, polarization, and interstellar lines of the surrounding ...
  • On the Balmer progression in the expanding shell of Pleione 
    Peraiah, A (Indian Academy of Sciences, 1982-09)
    An attempt has been made to explain the Balmer progression in velocities seen in Pleione and other shell stars. Equations of conservation of mass and momentum are simultaneously solved with assumptions which simplify the ...
  • Optical CCD imaging of some Herbig Ae/Be stars 
    Bhatt, H. C; Sagar, R (EDP Sciences, 1992-02)
    Results of V, R, and H-alpha CCD imaging for 15 Herbig Ae/Be stars are presented. Light variations of more than about 2 mag in V have been noticed in stars T Ori, RR Tau, and LH-alpha 25. The nature of the variations in ...
  • Photometric and radial velocity variations of RCrB near maximum light 
    Raveendran, A. V; Ashoka, B. N; Kameswara Rao, N (D. Reidel Publishing Co, 1986)
    Fourier analysis of the light curves of R CrB in the V band near maximum shows that in addition to several significant short periods there is a modulation of the visual light with a period around 1170 days, similar to that ...
  • Planetary nebulae and nitrogen enrichment in the galaxy 
    Mallik, D. C. V (Geneva Observatory, 1978)
    The extent of nitrogen enrichment of the interstellar gas by planetary-nebula formation is evaluated, and the nitrogen and oxygen abundance gradients in the disk of the Galaxy are derived on the basis of a simple model for ...
  • The R Coronae Borealis stars - A few mere facts 
    Lambert, D. L; Kameswara Rao, N (Indian Academy of Sciences, 1994-03)
    This review presents a selection of recent highlights of observations of R Coronae Borealis (RCB) variables. Emphasis is placed on an abundance analysis of a complete sample (18 stars) of the warm galactic RCBs. It is shown ...
  • Rapid continuum level variability in Be stars earlier than B2 
    Ghosh, K. K (American Astronomical Society, 1990-05)
    H-alpha profiles for 12 Be stars and four standard stars were obtained on six nights in January and February, 1988, in order to search for rapid spectral variability in these stars. The results show that the Be stars earlier ...
  • Rapid variations of H-alpha emission strength of eight Be stars 
    Ghosh, K. K (Kluwer Academic Publishers, 1988-08)
    Rapid observations of H profiles of eight Be stars have been obtained and it is found that rapid (in a time-scale of 4 to 6 minutes) and irregular variations of total emission strength of H line are present in these stars. ...
  • Relativistic star clusters with large central redshifts 
    Das, P. K (The Royal Astronomical Society, 1984-10)
    Previous calculations of the velocity distribution function for a star cluster scenario of a class of core-envelope type static, stable, massive equilibrium configurations, capable of giving high internal gravitational ...
  • Search for rapid spectral variability in Be stars - Alpha Columbae, Rho Carinae and Eta Centauri 
    Ghosh, K. K; Pukalenthi, S; Jaykumar, K; Kuppuswamy, K; Sanjeevkumar, T; Muniandi, A (European Southern Observatory, 1990-03)
    A series of H-alpha profiles (in total 1006 spectra in the H-alpha region) with the time resolution around 45 s were obtained on six nights between January 29 and February 7, 1988, to search for rapid spectral variability ...
  • Spectral evolution of nova V443 Scuti 1989 
    Anupama, G. C; Duerbeck, H. W; Prabhu, T. P; Jain, S. K (European Southern Observatory, 1992-09)
    Spectroscopy of the moderately fast nova V443 is presented. Observations were made during the brightness fluctuations following maximum and during the transition stage. A few broadband polarimetric observations are also ...
  • Spectrophotometry of Nova Coronae Austrinae, 1981 
    Shylaja, B. S (D. Reidel Publishing Co., 1984-10)
    Spectrophotometric observations of Nova Coronae Austrinae 1981, during its nebular phase are reported. The various emission lines are identified. The electron densities and the mass of the ionized hydrogen in the shell ...
  • Spectroscopic observations of delta orionis 
    Singh, M (Kluwer Academic Publishers, 1982-10)
    The H α profile in the spectrum of δ Orionis shows phase-dependent changes, with a period of variation equal to the orbital period fo the binary system. The profile shape changes from a normal absorption profile at zero ...

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