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Browsing by Subject "H Alpha Line"

Browsing by Subject "H Alpha Line"

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  • 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 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 eruption of prominences and disappearance of quiescent filaments 
    Singh, J; Gupta, S. S (Springer, 1995-05)
    We suggest the following heuristic model for the evolution of a quiescent filament. The middle part of the filament rises due to heating, while its ends remain anchored in the chromosphere; and a kink appears in the H alpha ...
  • Photometric calibration of the CCD camera of 1-m telescope at VBO 
    Mayya, Y. D (Indian Academy of Sciences, 1991-12)
    Calibration of the CCD camera of the 1-m telescope at the Vainu Bappu Observatory, Kavalur, to the BVR system is reported here based on the observations of stars in the 'dipper asterism' in the open cluster M 67 (NGC 2682). ...
  • Poleward migration of the magnetic neutral line and the reversal of the polar fields on the sun. II - Period 1904-1940 
    Makarov, V. I; Sivaraman, K. R (Springer, 1983-06)
    Poleward migration of the magnetic neutral line on the sun has been computed for the period 1904-1940 using synoptic charts based on H-alpha observations and the epochs of sign reversal of the solar magnetic field at ...
  • 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. ...
  • RS CVn-type variables. I - Photometry of HR 1099 
    Parthasarathy, M; Raveendran, A. V; Mekkaden, M. V (D. Reidel Publishing Co., 1981-01)
    Photometric observation of HR 1099 inV andB obtained on 18 nights between January and March 1977 is presented. The amplitude of the asymmetric light curve is found to be 0m.10±0m.004 both inV andB. On three occasions—namely, ...
  • 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 ...
  • 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 ...
  • Study of calcium-K network evolution from Antarctica 
    Singh, J; Nagabhushana, B. S; Babu, G. S. D; Uddin, Wahab (Springer, 1994-08)
    To study the evolution of large convective cells known as supergranules, a solar telescope was set up at Maitri, Indian permanent station in Antarctica region, during the local summer months (December 1989 through March ...
  • A study of the H-alpha line in late G and K supergiants 
    Mallik, S. G. V (Indian Academy of Sciences, 1982-03)
    H-alpha is investigated spectroscopically in order to gain information on the properties of expanding chromospheres of late G and K supergiants. Spectra of 23 stars brighter than V equals 6.0 are obtained at dispersions ...
  • Unidentified molecular features in the red spectrum (5800 to 7300 Å) of PI Gruis 
    Murty, P. S (D.Reidel Publishing Co.,, 1982-11)
    Moderate dispersion (46 Å mm–1 at H) image-tube spectrum (5800–7300 Å) of the S star 1 Gru is found to exhibit several unidentified molecular features, in addition to the well-known bands of the oxides ofs-process elements. ...

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