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Browsing by Author "Jayakumar, K"

Browsing by Author "Jayakumar, K"

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  • Detection of an extremely active state of AM Canum Venaticorum 
    Kutty, K. R. N; Marar, T. M. K; Padmini, V. N; Seetha, S; Kasturirangan, K; Rao, U. R; Bhattacharyya, J. C; Mohin, S; Jayakumar, K (D. Reidel Publishing Co., 1986)
    We report fast photometric observations of AM Canum Venaticorum (AM CVn), the ultrashort-period, hydrogen-deficient variable, are reported. An intense flare of (Delta m) peak roughly 0.34 was detected on February 24th, ...
  • Fiber-fed echelle spectrometer of the 2.34 meter Vainu Bappu Telescope 
    Kameswara Rao, N; Sriram, S; Gabriel, F; Prasad, B. R; Samson, J. P. A; Jayakumar, K; Srinivasan, R; Mahesh, P. K; Giridhar, S (Anita Publications, 2004-12)
    The optical design and performance of high resolution fiber-fed echelle spectrometer for the 2.34 meter Vainu Bappu Telescope (VBT) is described. An optical fiber of core 100 J-Lm and length 45 meter is used to link the ...
  • High Resolution Stellar Spectroscopy with VBT Echelle Spectrometer 
    Kameswara Rao, N; Sriram, S; Jayakumar, K; Gabriel, F (Indian Academy of Sciences, 2005-09)
    The optical design and performance of the recently commissioned fiber fed echelle spectrometer of 2.34 meter Vainu Bappu Telescope are described. The use of it for stellar spectroscopic studies is discussed.
  • Identification of emission bands in P/Halley 
    Bhattacharyya, J. C; Babu, G. S. D; Ghosh, K. K; Jayakumar, K; Appakutty, M (Indian Academy of Sciences, 1986)
    Spectrophotometric studies of P /Halley (r = 1.98 AU, Δ= 1.19AU, r = 1.97, Δ = 1.16 AU and r = 1.95 AU, Δ. = 1.13 AU) in the spectral range 3900 A - 6450 A were made on three nights and identifications of emission features ...
  • A new three-band, two beam astronomical photo-polarimeter 
    Srinivasulu, G; Raveendran, A. V; Muneer, S; Mekkaden, M. V; Jayavel, N; Somashekar, M. R; Sagayanathan, K; Ramamoorthy, S; Rosario, M.; Jayakumar, K (Astronomical Society of India, 2014-09)
    We designed and built a new astronomical photo-polarimeter that can measure linear polarization simultaneously in three spectral bands. It has a Calcite beamdisplacement prism as the analyzer. The ordinary and extra-ordinary ...
  • Observations of occulation of HIP 66446 by (423) Diotima on 2001 March 15 from India - Detection of a companion to the star 
    Vasundhara, R; Jayakumar, K; Velu, C; Appakutty, M; Paranjpye, A; Kulkarni, H; Nitsure, P; Prabhunne, M; Shah, K (Astronomical Society of India, 2001)
    Observations of the occulation of the star HIP 66446 by (423) Diotima on 2001 March 15 made by the team at the Vainu Bappu Observatory and three mobile teams at Ganeshgudi, Londa and the CES Field Research Station at Sirsi ...
  • Orbital period modulation and spot activity in the RS CVn binary V711 Tauri 
    Muneer, S; Jayakumar, K; Rosario, M. J; Raveendran, A. V; Mekkaden, M. V (EDP Sciences, 2010-10)
    We attempt to establish the real nature of the orbital period variation and its relation to the spot activity of V711 Tau, and determine why the (B–V) colour of the star appears to be nearly independent of its V magnitude. ...
  • 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 ...
  • Recent photometry of HR 1099 (V711 Tau) 
    Mohin, S; Raveendran, A. V; Mekkaden, M. V; Jayakumar, K; Rosario, M. J (Konkoly Observatory, 1982-08)
  • Spectral Line Variations in the Ap Star HD 42536 
    Babu, G. S. D; Jayakumar, K; Velu, C; Sujatha, S (Astronomical Society of India, 2003)
    The Sr-Cr type chemically peculiar star HD 42536 (= HR 2195) was observed with the 2.34 meter Vainu Bappu Telescope. Kavalur during the period of November 1998 to April 1999. A total of 46 spectrograms were obtained in the ...
  • A spectroscopic study of the hybrid pulsator Gamma Pegasi 
    Pandey, C. P; Morel, T; Briquet, M; Jayakumar, K; Bisht, S; Sanwal, B. B (Austrian Academy of Sciences Press, 2011-02)
    The recent detection of both pressure and high-order gravity modes in the clas- sical B-type pulsator γ Pegasi offers promising prospects for probing its internal structure through seismic studies. To aid further modelling ...
  • A study of K i 7699 Å and related shell lines during the recent eclipse of ϵ Aurigae 
    Muthumariappan, C; Parthasarathy, M; Leadbeater, R; Potravnov, I. S; Appakutty, M; Jayakumar, K (Oxford University Press on behalf of the Royal Astronomical Society, 2014-12-11)
    We report high-resolution (R = 30 000, 45 000 and 75 000) echelle and medium-resolution (R = 22 000 and 10 000) spectroscopic observations of the long-period, eclipsing binary ε Aurigae during the 2009 - 2011 eclipse. ...
  • Variation of the Si II features in the chemically peculiar star - HD 115735 
    Sriraghavan, S. M; Jayakumar, K; Babu, G. S. D; Sujatha, S (Astronomical Society of India, 2004-06)
    The chemically peculiar star HD 115735 (= HR 5023 = 21 CVn) was observed with the 2.34 meter Vainu Bappu Telescope at Kavalur during the period of January 1999 to April 2000. A total of 47 spectrograms were obtained in the ...
  • VRI photometry of LMC SN 1987A 
    Rangarajan, K. E; Jayakumar, K; Appakutty, M; Sheriff, H. D (Konkoly Observatory, 1987-07)
  • ɛ Aur in eclipse: Post-AGB primary and disk-shaped secondary 
    Muthumariappan, C; Parthasarathy, M; Jayakumar, K; Appakutty, M (Cambridge University Press, 2012-08)
    We present physical and chemcal properties of the disk in the eclipsing binary system ɛ Aur by solving 2D radiative transfer problem. We also present preliminary results of our high resolution spectroscopic monitoring of ...

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