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Browsing by Subject "Stars: Population II"

Browsing by Subject "Stars: Population II"

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  • Abundance analysis of SDSS J134338.67+484426.6; an extremely metal-poor star from the MARVELS pre-survey 
    Susmitha Rani, A; Sivarani, T; Beers, T. C; Fleming, S; Mahadevan, S; Ge, J (Oxford University Press on behalf of the Royal Astronomical Society, 2016-05)
    We present an elemental-abundance analysis of an extremely metal-poor (EMP; [Fe/H] <−3.0) star, SDSS J134338.67+484426.6, identified during the course of the Multi-object Apache Point Observatory Radial Velocity Exoplanet ...
  • CH stars at high Galactic latitudes 
    Goswami, A (Blackwell Publishing, 2005-05)
    Carbon-rich stars of Population II, such as CH stars, can provide direct information on the role of low- to intermediate-mass stars of the halo in early Galactic evolution. Thus accurate knowledge of the CH stellar population ...
  • Chemical analysis of CH stars – I. Atmospheric parameters and elemental abundances 
    Drisya, K; Goswami, A (Oxford University Press on behalf of the Royal Astronomical Society, 2014-05-11)
    Results from high-resolution spectral analyses of a selected sample of CH stars are presented. Detailed chemical composition studies of these objects, which could reveal abundance patterns that in turn provide information ...
  • Chemical analysis of CH stars – II. Atmospheric parameters and elemental abundances 
    Drisya, K; Goswami, A (Oxford University Press on behalf of the Royal Astronomical Society, 2015-01-21)
    We present detailed chemical analyses for a sample of 12 stars selected from the CH star catalogue of Bartkevicius. The sample includes two confirmed binaries, four objects that are known to show radial velocity variations ...
  • Chemical analysis of three barium stars: HD 51959, HD 88035, HD 121447 
    Drisya, K; Goswami, A; Sridhar, N; Masseron, T; Meenakshi, P (Oxford University Press on behalf of the Royal Astronomical Society, 2018-05)
    We present elemental abundance results from high-resolution spectral analysis of three nitrogen-enhanced barium stars. The analysis is based on spectra obtained with the fibre- fed extended range optical spectrograph ...
  • Chemical composition of UV-bright star ZNG 4 in the globular cluster M 13 
    Ambika, S; Parthasarathy, M; Aoki, W; Fujii, T; Nakada, Y; Ita, Y; Izumiura, H (EDP Sciences, 2004-04)
    We present a detailed model-atmosphere analysis of ZNG 4, a UV-bright star in the globular cluster M 13. From the analysis of a high resolution ( R ≈ 45 000 ) spectrum of the object, we derive the atmospheric parameters ...
  • HD209621: abundances of neutron-capture elements 
    Goswami, A; Aoki, W (Blackwell Publishing, 2010-05)
    High-resolution spectra obtained from the Subaru Telescope High Dispersion Spectrograph have been used to update the stellar atmospheric parameters and metallicity of the star HD 209621. We have derived a metallicity of ...
  • Low-resolution spectroscopy of high galactic latitude objects: a search for CH stars 
    Goswami, A; Bama, P; Shantikumar, N. S; Devassy, D (Astronomical Society of India, 2007-09)
    Properties of CH stars like iron deficiency and enrichment of carbon and heavy elements can provide valuable inputs to our understanding of nucleosynthesis. In particular, these parameters provide strong observational ...
  • The metal-poor end of the Spite plateau I. Stellar parameters, metallicities, and lithium abundances 
    Sbordone, L; Bonifacio, P; Caffau, E; Ludwig, H. -G; Behara, N. T; González Hernández, J. I; Steffen, M; Cayrel, R; Freytag, B; Van’t Veer, C; Molaro, P; Plez, B; Sivarani, T; Spite, M; Spite, F; Beers, T. C; Christlieb, N; François, P; Hill, V (EDP Sciences, 2010-11)
    Context. The primordial nature of the Spite plateau is at odds with the WMAP satellite measurements, implying a primordial Li production at least three times higher than observed. It has also been suggested that A(Li) might ...
  • The metal-poor end of the Spite plateau. II. Chemical and dynamical investigation 
    Pinto, A. M. Matas; Spite, M; Caffau, E; Bonifacio, P; Sbordone, L; Sivarani, T; Steffen, M; François, P; Di Matteo, P (EDP Sciences, 2021-10)
    Context. The study of old, metal-poor stars deepens our knowledge on the early stages of the universe. In particular, the study of these stars gives us a valuable insight into the masses of the first massive stars and their ...
  • Optical and NIR spectroscopy of cool CEMP stars to probe the nucleosynthesis in low-mass AGB binary system 
    Susmitha, A; Ojha, D. K; Sivarani, T; Ninan, J. P; Bandyopadhyay, A; Surya, Arun; Unni, Athira (Oxford University Press on behalf of Royal Astronomical Society, 2021-09)
    We present the abundance analyses of seven carbon enhanced metal-poor (CEMP) stars to understand the origin of carbon in them. We used high-resolution optical spectra to derive abundances of various elements. We also used ...
  • A Search for Unrecognized Carbon-Enhanced Metal-Poor Stars 
    Placco, V. M; Kennedy, C. R; Rossi, S; Beers, T. C; Christlieb, N; Sivarani, T (Cambridge University Press, 2010-03)
    We have developed a new procedure to search for Carbon-Enhanced Metal-Poor (CEMP) stars from the Hamburg/ESO (HES) prism-survey plates. This method uses an extended line index for the CH G-band, which we demonstrate to ...
  • A search for unrecognized carbon-enhanced metal-poor stars in the galaxy 
    Placco, V. M; Kennedy, C. R; Rossi, S; Beers, T. C; Lee, Y. S; Christlieb, N; Sivarani, T; Reimers, D; Wisotzki, L (Institute of Physics, 2010-03)
    We have developed a new procedure to search for carbon-enhanced metal-poor (CEMP) stars from the Hamburg/ESO (HES) prism-survey plates. This method employs an extended line index for the CH G band, which we demonstrate to ...
  • Searches for Metal-poor Stars from the Hamburg/ESO Survey Using the CH G Band 
    Placco, V. M; Kennedy, C. R; Beers, T. C; Christlieb, N; Rossi, S; Sivarani, T; Lee, Young Sun; Reimers, D; Wisotzki, L (IOP Publishing, 2011-12)
    We describe a new method to search for metal-poor candidates from the Hamburg/ESO objective-prism survey (HES) based on identifying stars with apparently strong CH G-band strengths for their colors. The hypothesis we exploit ...

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