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Browsing by Author "Giridhar, S"

Browsing by Author "Giridhar, S"

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  • Chemical composition of A–F type post-AGB candidates 
    Giridhar, S; Molina, R; Arellano Ferro, A; Selvakumar, G (Wiley-Blackwell, 2010-07)
    An abundance analysis has been conducted for a sample of nine post-AGB candidate stars; eight of them have not been explored before.We find four very promising objects like HD 105262, HD 53300 and CpD−62o5428 among them. ...
  • Chemical composition of evolved stars of high galactic latitude 
    Giridhar, S; Arellano Ferro, A (EDP Sciences, 2005-11)
    We have carried out abundance analysis for a sample of high galactic latitude supergiants in search of evolved stars. We find that HD 27381 has atmospheric parameters and an abundance pattern very similar to that of the ...
  • 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 ...
  • Chemical Composition of Two Bright, Extremely Metal-poor Stars from the SDSS MARVELS Pre-survey 
    Bandyopadhyay, A; Sivarani, T; Susmitha, A; Beers, T. C; Giridhar, S; Arun Surya; Masseron, T (IOP Publishing, 2018-06-01)
    SDSS J082625.70+612515.10 (V = 11.4; [Fe/H] = −3.1) and SDSS J134144.60+474128.90 (V = 12.4; [Fe/H] = −3.2) were observed with the SDSS 2.5m telescope as part of the SDSS MARVELS spectroscopic pre-survey and identified ...
  • Chemical Compositions of Four Metal-poor Giant Stars 
    Giridhar, S; Lambert, D. L; Gonzalez, G; Pandey, G (University of Chicago Press, 2001-05)
    We present the chemical compositions of four K giants (CS 22877-1, CS 22166-16, CS 22169-35, and BS 16085-0050) that have [Fe/H] in the range -2.4 to -3.1. Metal-poor stars with [Fe/H]<-2.5 are known to exhibit considerable ...
  • Chemical Compositions of RV Tauri Stars and Related Objects 
    Sumangala Rao, S; Giridhar, S (Institute de Astronomia, 2014-04)
    We have undertaken a comprehensive abundance analysis for a sample of relatively unexplored RV Tauri and RV Tauri like stars to further our understanding of post-Asymptotic Giant Branch (post-AGB) evolution. From our study ...
  • The Chemical Compositions of the SRd Variable Stars. I. XY Aquarii, RX Cephei, AB Leonis, and SV Ursae Majoris 
    Giridhar, S; Lambert, D. L; Gonzalez, G (The Astronomical Society of the Pacific, 1998-06)
    Chemical compositions are derived from high-resolution spectra for four stars classed as SRd variables in the General Catalogue of Variable Stars. Two stars—XY Aquarii and RX Cephei—are of solar metallicity and most likely ...
  • The Chemical Compositions of the SRD Variable Stars. II. WY Andromedae, VW Eridani, and UW Librae 
    Giridhar, S; Lambert, D. L; Gonzalez, G (The Astronomical Society of the Pacific, 1999-10)
    Chemical compositions are derived from high-resolution spectra for three stars classed as SRd variables in the General Catalogue of Variable Stars. These stars are shown to be metal-poor supergiants: WY And with [Fe/H]=-1.0, ...
  • The Chemical Compositions of the SRD Variable Stars. III. KK Aquilae, AG Aurigae, Z Aurigae, W Leo Minoris, and WW Tauri 
    Giridhar, S; Lambert, D. L; Gonzalez, G (The Astronomical Society of the Pacific, 2000-12)
    Chemical compositions are derived from high-resolution spectra for five field SRd variables. These supergiants not previously analyzed are shown to be metal poor: KK Aql with [Fe/H]=-1.2, AG Aur with [Fe/H]=-1.8, Z Aur ...
  • The Chemical Compositions of the Type II Cepheids-The BL Herculis and W Virginis Variables 
    Maas, T; Giridhar, S; Lambert, D. L (University of Chicago Press, 2007-09)
    Abundance analyses from high-resolution optical spectra are presented for 19 type II Cepheids in the Galactic field. The sample includes both short-period (BL Her) and long-period (W Vir) stars. This is the first extensive ...
  • Classical Cepheids and the local chemical inhomogeneities in the galactic disc 
    Giridhar, S (1986-06)
    Places of formation have been derived for a sample of 23 Cepheids with well-determined atmospheric abundances in an attempt to study the chemical inhomogeneities in the local interstellar medium. The abundance data available ...
  • Comments on the variability and physical parameters of the F supergiant Phi Cassiopeiae 
    Ferro, A. A; Parrao, L; Giridhar, S (Astronomical Society of the Pacific, 1988-08)
    UBVRI and uvby photometry and radial velocities have been obtained for the F0 Ia supergiant Phi Cas. The variability is confirmed from the radial velocities; the velocity range is small (Delta V/subr of about 6 km/s). No ...
  • Commission 45: Spectral classification 
    Giridhar, S; Gray, R. O; Corbally, C. J; Bailer-Jones, C. A. L; Eyer, L; Irwin, M. J; Davy Kirkpatrick, J; Majewski, S; Minniti, D; Nordstrom, B (Cambridge University Press, 2009)
    This report gives an update of developments (since the last General Assembly at Prague) in the areas that are of relevance to the commission. In addition to numerous papers, a new monograph entitled Stellar Spectral ...
  • Commission 45: Stellar Classification 
    Corbally, C; Giridhar, S; Bailer-Jones, C; Humphreys, R; Kirkpatrick, D; Lloyd Evans, T; Luri, X; Minniti, D; Pasinetti, L; Straižys, V; Weiss, W (Cambridge University Press, 2007)
    This report, like its predecessors, focuses on areas which have been especially active since the last General Assembly. Two major developments have been the unification of the T-dwarf standards and the new general catalogue ...
  • Comprehensive abundance analysis of red giants in the open clusters NGC 1342, 1662, 1912, 2354 and 2447 
    Reddy, A. B. S; Giridhar, S; Lambert, D. L (Oxford University Press on behalf of the Royal Astronomical Society, 2015-07-11)
    We have observed high-dispersion echelle spectra of red giant members in the five open clusters (OCs) NGC 1342, NGC 1662, NGC 1912, NGC 2354 and NGC 2447 and determined their radial velocities and chemical compositions. ...
  • Comprehensive abundance analysis of red giants in the open clusters NGC 2527, 2682, 2482, 2539, 2335, 2251 and 2266 
    Reddy, A. B. S; Giridhar, S; Lambert, D. L (Oxford University Press on behalf of the Royal Astronomical Society, 2013-06-01)
    We have analysed high-resolution echelle spectra of red giant members for seven open clusters in the Galactic anticentre direction to explore their chemical compositions. Cluster membership has been confirmed by radial ...
  • Comprehensive abundance analysis of red giants in the open clusters NGC 752, 1817, 2360 and 2506 
    Reddy, A. B. S; Giridhar, S; Lambert, D. L (Wiley-Blackwell, 2012-01)
    We have analysed high-dispersion echelle spectra (R ≳ 50 000) of red giant members for four open clusters to derive abundances for many elements. The spread in temperatures and gravities being very small among the red ...
  • Constraining the parameters of globular cluster NGC 1904 from its variable star population 
    Kains, N; Bramich, D. M; Figuera Jaimes, R; Arellano Ferro, A; Giridhar, S; Kuppuswamy, K (EDP Sciences, 2012-12)
    Aims. We present the analysis of 11 nights of V and I time-series observations of the globular cluster NGC 1904 (M 79). Using this we searched for variable stars in this cluster and attempted to refine the periods of known ...
  • Coronal photography at H alpha 
    Rangarajan, K. E; Giridhar, S (Indian National Science Academy, 1981)
  • A critical compilation of oscillator strengths for Fe II lines. 
    Giridhar, S; Arellano Ferro, A (Mexicana de Astronomia y Astrofisica, 1995-04)
    We have compiled oscillator strengths for 848 Fe II lines of astrophysical interest. The Oscillator strengths from various sources like laboratory measurements, semi-empirical estimates and those derived using solar Fe II ...

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