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Browsing by Subject "B Stars"

Browsing by Subject "B Stars"

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  • 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 ...
  • 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 ...
  • Flare-like activity in Be stars HR 7403 and .8762 
    Ghosh, K. K (D. Reidel Publishing Co., 1989-05)
    Results are presented from rapid spectrophotometric observations of the Be stars HR 7403 and HR 8762. The observations were conducted between November, 1984 and December, 1985. No ultrarapid variations were detected in the ...
  • Observation of an H-alpha outburst in the Be star HR 4123 
    Ghosh, K. K; Apparao, K. M. V; Tarafdar, S. P (American Astronomical Society, 1989-09)
    During routine monitoring of the Be star HR 4123 during the year 1987-1988, a burst of H-alpha emission was observed on May 11, 1987. The increase was observed on May 9 and lasted until June 7, peaking to an equivalent ...
  • Observations of X-Per in optical domain 
    Sharma, D. P; Nagaraja, B. V; Bhattacharyya, J. C; Mohin, S; Raveendran, A. V (Kluwer Academic Publishers, 1983-09)
    We have monitored the X-ray source X-Per (4U 0352+30) on 31 August, 1979 through aU filter for about 1.5 hr using 102-cm telescope of Kavalur observatory. During this period intensity of X-Per fluctuated for some time, on ...
  • 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 ...
  • Optical colours and polarization of a model reflection nebula. III - Composite and mixture of grains in the nebula with the star in the rear 
    Shah, G. A (Indian Academy of Sciences, 1977-11)
    The colour differences between the star and the associated reflection nebula and polarization caused by core mantle grains and mixture of grains have been given. They are based on homogeneous plane-parallel slab-model of ...
  • Possible young stellar objects in the region of the Cygnus OB2 (VI Cygni) association from IRAS observations 
    Parthasarathy, M; Jain, S. K; Bhatt, H. C (EDP Sciences, 1992-12)
    Several massive young stellar objects are found from an analysis of the 12- to 100-micron flux data of IRAS sources in the region of the Cyg OB2 association. Sixty-four sources with positive spectral indices and steeply ...
  • 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 H-alpha variability in Phi Persei 
    Ghosh, K. K; Sanjeevkumar, T; Jaykumar, K; Kuppuswamy, K; Rosario, M. J (Astronomical Society of the Pacific, 1988-06)
    A search for rapid variability of H-alpha with a time resolution from 30 to 45 seconds is performed for Phi Per. In total, 42 spectra in H-alpha were obtained during three nights. Results show the presence of rapid irregular ...
  • Rapid simultaneous observations of Fe II and Balmer emission lines of X OPH 
    Ghosh, K. K; Jayakumar, K (D. Reidel Publishing Co., 1988-02)
    Sudden brightening of Fe II and Balmer (Hβ and Hα) lines of X Oph was observed on 28 - 29 May, 1986. Equivalent width of Fe II and Hβ lines increased by a factor of two and that for Hα line by a factor of four, during the ...
  • 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. ...
  • Red and blue stars in the direction of the Large Magellanic Cloud 
    Parthasarathy, M (International Astronomical Union, 1978)
    The Large Magellanic Cloud has been surveyed on ultralow dispersion (10,000 A/mm) plates taken with the 102-centimeter reflector at Kavalur. Many new red and blue stars were found. The LMC bar was found to have a strong ...
  • Search for rapid H-alpha variability studies in Be stars - 28 Eri, X Ophiuchi, 66 Ophiuchi and Pi Aquarii 
    Ghosh, K. K (EDP Sciences, 1988-10)
    In order to search for rapid Hα variability in Be stars, a series of Hα profiles were observed on a time scale of few minutes for 28 Eri, X Oph, 66 Oph and π Aqr. In total, 95 and 54 Hα profiles were obtained for the program ...
  • 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 ...
  • Search for rapid spectral variability in Psi(9) Aurigae 
    Ghosh, K. K (Astronomical Society of the Pacific, 1989-09)
    Observations of Psi(9) Aur on five nights between January 29 and February 3, 1988 were conducted as part of a search for rapid spectral variability in Be stars. In addition, a series of H-alpha profiles with a time resolution ...
  • Search for rapid V/R variability in Eta CEN 
    Ghosh, K. K (Royal Astronomical Society, 1989-10)
    In order to search for rapid V/R variability in the Be star, Eta Cen, a series of H-alpha profiles of this star were observed on three nights between May 28 and June 3, 1986. A method of estimating the standard deviation ...
  • 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 ...
  • UBV Observations of R-Coronae Type Variables and Related Objects 
    Kameswara Rao, N (D. Reidel Publishing Co., 1980-07)
    UBV observations obtained during the period 1972-73 are presented for the following five R CrB stars: GU Sgr, SU Tau, XX CAm, DZ And, V973 Oph, and the hydrogen-poor, carbon-rich stars BD + 10 deg 2179 and HD 137613. ...

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