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Browsing by Author "Giridhar, S"

Browsing by Author "Giridhar, S"

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  • 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 ...
  • 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. ...
  • Galactic chemical evolution and chemical tagging with open clusters 
    Reddy, A. B. S; Giridhar, S; Lambert, D. L (Indian Academy of Sciences, 2020-12)
    The article presents the consolidated results drawn from the chemical composition studies of Reddy et al. (2012, 2013, 2015, 2016) and Reddy & Lambert (2019), who through the high-dispersion echelle spectra (R=60000) of ...
  • The Globular cluster M10: reassessment of stellar membership, distance, and age using its variable and HB stars 
    Arellano Ferro, A; Yepez, M. A; Muneer, S; Bustos Fierro, I. H; Schroder, K. P; Giridhar, S; Calderon, J. H (Oxford University Press on behalf of the Royal Astronomical Society, 2020-12)
    Time-series VI CCD photometry of the globular cluster M10 (NGC 6254) is employed to perform a detailed identification, inspection of their light curves, their classification, and their cluster membership, of all the known ...
  • Hanle echelle spectrograph: design and performance 
    Sriram, S; Amit Kumar; Arun Surya; Sivarani, T; Giridhar, S; Kathiravan, S; Anand, M. N; Jones, D; Grobler, D; Jakobsson, R; Anantha, Ch; Athira Unni; Angchuk, D; Tsewang, D; Gyalson, T (SPIE-The International Society for Optical Engineering, 2018-07-06)
    Hanle echelle spectrograph (HESP) is a high resolution, bench mounted, fiber-fed spectrograph at visible wavelengths. The instrument was recently installed at the 2m Himalayan Chandra Telescope (HCT), located at Indian ...
  • HD 34700: A new T Tauri double-lined spectroscopic binary 
    Arellano, F. A; Giridhar, S (The European Southern Observatory, 2003-09)
    We find the star HD 34700 to be a double-lined spectroscopic binary. We also identify it as a weak-line T Tauri object. The spectra of both components are very similar and both show the Li I feature at 6708 Å. Strong ...
  • The He II 5411 Å velocity curve of the Wolf-Rayet eclipsing system HD 214419 
    Giridhar, S (Indian Institute of Astrophysics, 1978)
    A velocity curve of the Wolf-Rayet eclipsing system HD 214419 is obtained from measures on prismatic spectra of the Hell 5411 emission line. The shape of the velocity curve is unlike that obtained for Hell 4686. The emission ...
  • High resolution spectroscopy of R Coronae Borealis during the 1988-1989 minimum 
    Lambert, D. L; Kameswara Rao, N; Giridhar, S (Indian Academy of Sciences, 1990-12)
    Moderate-resolution spectra of the C2 Swan 0-1 bandhead, the Na I D lines and the K I resonance lines near 7660 A obtained at minimum light during the 1988-1989 decline of R CrB are discussed and interpreted in terms of a ...
  • High Resolution Spectroscopy of the Semi-Regular Variable LR Sco 
    Giridhar, S; Kameswara Rao, N; Lambert, D. L (Indian Academy of Sciences, 1992)
    A detailed spectroscopic investigation of LR Sco which was earlier misclassified as R CrB star is made. Atmospheric parameters and elemental abundances are determined using detailed depth-dependent model atmospheres and ...
  • High resolution spectroscopy with a 10-m class telescope 
    Giridhar, S (Astronomical Society of India, 2000)
  • The hot R Coronae Borealis star DY Centauri: Nebular and photospheric lines 
    Kameswara Rao, N; Giridhar, S; Lambert, D. L (The European Southern Observatory, 1993-12)
    High resolution spectra in the red region of the hot R CrB star DY Cen show the following characteristics: a strong absorption line spectrum dominated by lines of C II, N II, and Ne I inverse P-Cygni type profiles of some ...
  • Identification of metal-poor stars using the artificial neural network 
    Giridhar, S; Goswami, A; Kunder, A; Muneer, S; Selvakumar, G (EDP Sciences, 2013-08)
    Context. Identification of metal-poor stars among field stars is extremely useful for studying the structure and evolution of the Galaxy and of external galaxies. Aims. We search for metal-poor stars using the artificial ...
  • Image processing facilities at Vainu Bappu observatory 
    Giridhar, S; Bhattacharyya, J. C; Kutty, K. N (Tata Institute of Fundamental Research, 1988)
    Need for application of Image processing techniques in astronomical studies in optical wavelengths and special advantages accruing thereby are discussed. The paper describes various image processing facilities that are ...
  • Important parameters of four small-amplitude cepheids from uvby photometry 
    Arellano Ferro, A; Giridhar, S; Parrao, L (Konkoly Observatory, 1987-08)
  • An internally consistent set of oscillator strengths for Fe I lines 
    Giridhar, S; Ferro, A. A (Indian Academy of Sciences, 1989-03)
    An extensive set of internally consistent oscillator strength values for Fe I lines is compiled using literature data and scaling the oscillator strengths derived by different workers to that of Blackwell and his coworkers. ...
  • Investigation of variable star candidates in the globular cluster NGC 5024 (M53) 
    Bramich, D. M; Arellano Ferro, A; Figuera Jaimes, R; Giridhar, S (Wiley-Blackwell, 2012-08)
    We have performed a careful investigation of the 74 candidate variable stars presented by Safonova & Stalin. For this purpose we used our data base of imaging and light curves from Arellano Ferro et al. We find that two ...
  • Is LR SCO and RCB star? 
    Giridhar, S; Kameswara Rao, N; Lambert, D. L (The Observatory, 1990-08)
  • Is the Post-AGB Star SAO 40039 Mildly Hydrogen-Deficient? 
    Sumangala Rao, S; Pandey, G; Lambert, D. L; Giridhar, S (IOP Publishing, 2011-08-10)
    We have conducted an LTE abundance analysis for SAO 40039, a warm post-AGB star whose spectrum is known to show surprisingly strong He I lines for its effective temperature and has been suspected of being H-deficient and ...
  • A Li-rich post-AGB star HD 172481 
    Giridhar, S; Arellano Ferro, A; Mathias, P (Astronomical Society of India, 2001)
    Our abundance analysis of this post-AGB candidate star confirms that the HD 172481 is indeed a post-AGB star. It belongs to an important, but relatively rare class of post-AGB stars showing Li I features in their spectra. ...
  • A new discussion on the M(v) - W(O I 7774 A) relationship for F-G stars in the light of high-resolution data 
    Arellano Ferro, A; Giridhar, S; Goswami, A (Royal Astronomical Society, 1991-05)
    High-resolution CCD data and a large group of F-G stars of fundamentally determined distances are used here to investigate the intrinsic nature of the M(v) - W(O I) relation and the effect of other atmospheric parameters ...

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