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Browsing IIAP Publications by Subject "H Alpha Line"

Browsing IIAP Publications by Subject "H Alpha Line"

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  • The chemical composition of the RV Tauri variable IW Carinae 
    Giridhar, S; Kameswara Rao, N; Lambert, D. L (The American Astronomical Society, 1994-12)
    Analysis of the RV Tauri star IW Carinae shows a photospheric composition unlike that reported previously for a few other RV Tau stars but resembling that of certain post-asymptotic giant branch stars (post-AGB) stars. IW ...
  • Consequences of a chromospheric temperature rise on the formation of the H-alpha line in late-type supergiants 
    Mallik, S. G. V; Mallik, D. C. V (Royal Astronomical Society, 1988-08)
    Computations of the H-alpha line profiles were performed in a non-LTE moving chromosphere with temperature rise to simulate the observed H-alpha characteristics in G and K supergiants. The comoving frame radiative transfer ...
  • Dust and ionized gas in NGC 3607 
    Singh, K. P; Prabhu, T. P; Kembhavi, A. K; Bhat, P. N (The American Astronomical Society, 1994-04)
    We report the detection of a broad dust ring in the X-ray-bright elliptical galaxy NGC 3607, the dominant member of a nearby group of galaxies. The inner radius of the ring is approximately 1.3 kpc from the nucleus and has ...
  • Embedded clusters in giant extragalactic H II regions, 1: BVRH-alpha photometry 
    Mayya, Y. D (The American Astronomical Society, 1994-10)
    Photometry in BVR continuum bands and in the emission line of H-alpha+(N II) are presented for a sample of H II complexes in disk, spiral arm and nuclear regions of galaxies NGC 1365, 1566, 2366, 2903, 2997, 3351, 4303, ...
  • 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 ...
  • 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 ...
  • Further spectroscopic observations of SN 1987A 
    Anupama, G. C; Prabhu, T. P; Ghosh, K. K; Ashoka, B. N; Giridhar, S (Elsevier, 1988)
    Spectroscopic observations of SN 1987a obtained during 1987 August 30 – September 8 from Vainu Bappu Observatory, Kavalur, are presented; the spectrum is compared and contrasted with the spectra recorded at earlier epochs. ...
  • H-alpha flare of 14 March, 1984 -- Evidence for reconnection? 
    Sundararaman, K; Aleem, S. M; Singh, J; Selvendran, R; Thiagarajan, R (Springer, 1994-01)
    Kodaikanal H-alpha monochromatic and white-light observations are used to study the circular flare of 14 March, 1984. We report here the dynamic activity of the H-alpha filament, which attained a severe twist before erupting ...
  • The H-alpha line profile in early type-binary systems HD 47129 and Gamma Velorum 
    Rajamohan, R (Kluwer Academic Publishers, 1984-02)
    A brief description of the variation of the Hα line profile in γ Velorum and HD 47129 is given.
  • High-resolution studies of forbidden O I and NH2 line emissions at 6300 A in Halley's comet 
    Prasad, C. D; Chandrasekhar, T; Desai, J. N; Ashok, N. M; Sivaraman, K. R; Rajmohan, R (Astronomical Society of the Pacific, 1988-06)
    The forbidden O I line and NH2 (0-8-0) emissions of Comet Halley at about 6300 A were observed during April 1986 using a Fabry-Perot spectrometer with a resolution of about 0.14 A. The forbidden O I line and NH2 rotational ...
  • Morphology of H-alpha filaments and filament channel systems 
    Makarov, V. I; Stoianova, M. N; Sivaraman, K. R (Indian Academy of Sciences, 1982-12)
    The results of a study of the morphology of the large-scale filament structures of the sun and their relations with the distribution of the large-scale magnetic field on the solar surface are reported. A continuous filament ...
  • Morphology of the bipolar planetary nebula NGC 2346 from emission line profile studies 
    Anandarao, B. G; Banerjee, D. P. K; Desai, J. N; Jain, S. K; Mallik, D. C. V (Royal Astronomical Society, 1988-11)
    High resolution observations of H-alpha 6563-A, forbidden O-III 5007 A, and forbidden N-II 6583-A emission lines in the bipolar planetary nebula NGC 2346 are presented. From the widths of the alpha and forbidden N-II lines, ...
  • 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 ...

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