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Browsing by Author "Aoki, W"

Browsing by Author "Aoki, W"

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  • Carbon-enhanced Metal-poor Stars in the Inner and Outer Halo Components of the Milky Way 
    Carollo, D; Beers, T. C; Bovy, Jo; Sivarani, T; Norris, J. E; Freeman, K. C; Aoki, W; Lee, Young Sun; Kennedy, C. R (IOP Publishing, 2012-01-10)
    Carbon-enhanced metal-poor (CEMP) stars in the halo components of the Milky Way are explored, based on accurate determinations of the carbon-to-iron ([C/Fe]) abundance ratios and kinematic quantities for over 30,000 ...
  • The chemical composition of the post-asymptotic giant branch F supergiant CRL 2688 
    Ishigaki, M. N; Parthasarathy, M; Reddy, B. E; García-Lario, P; Takeda, Y; Aoki, W; García-Hernández, D. A; Manchado, A (Wiley-Blackwell, 2012-09)
    We present an analysis of a high-resolution (R ∼ 50 000) optical spectrum of the central region of the protoplanetary nebula CRL 2688. This object is thought to have recently moved off the asymptotic giant branch (AGB) and ...
  • 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 ...
  • Concerning the Li-rich status of KIC 9821622: a Kepler field RGB star reported as a Li-rich giant 
    Raghubar Singh; Bharat Kumar, Y; Reddy, B. E; Aoki, W (Oxford University Press on behalf of the Royal Astronomical Society, 2020-01)
    Given the implications for the origin of Li enhancement in red giants, we have reviewed the Li-rich classification of KIC 9821622, the only bonafide red giant branch (RGB) giant with a He inert core to date, reported as a ...
  • Contribution of HdC Stars to the Galactic Enrichment: The Sr-rich HdC Star HE 1015-2050 
    Goswami, A; Aoki, W (Astronomical Society of the Pacific, 2012-08)
    A fraction of the rare class of Hydrogen-deficient carbon (HdC) stars in our Galaxy are known to exhibit strong features of light neutron-capture elements such as Sr, Y and Zr usually attributed to the weak component of ...
  • Detection of Zinc in the Very Metal-Poor Post-AGB Star HR 4049 
    Takeda, Yoichi; Parthasarathy, M; Aoki, W; Ita, Yoshifusa; Nakada, Yoshikazu; Izumiura, Hideyuki; Noguchi, Kunio; Takada-Hidai, Masahide; Sato, B; Tajitsu, Akito; Honda, Satoshi; Kawanomoto, Satoshi; Ando, Hiroyasu; Karoji, Hiroshi (Astronomical Society of Japan, 2002-10-25)
    We report on the detection of two Zn I lines at 4722.15Å and 4810.53Å in the high-quality spectrum of the very metal-poor post-AGB star HR 4049, which was obtained with the High Dispersion Spectrograph attached to the ...
  • Gaia DR2 data and the evolutionary status of eight high-velocity hot post-AGB candidates 
    Parthasarathy, M; Matsuno, T; Aoki, W (Oxford University Press on behalf of the Astronomical Society of Japan, 2020-12)
    From Gaia DR2 data of eight high-velocity hot post-AGB candidates, LS 3593, LSE 148, LS 5107, HD 172324, HD 214539, LS IV −12 111, LS III +52 24, and LS 3099, we found that six of them have accurate parallaxes which made ...
  • 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 ...
  • A high-resolution spectral analysis of three carbon-enhanced metal-poor stars 
    Goswami, A; Aoki, W; Beers, T. C; Christlieb, N; Norris, J. E; Ryan, S. G; Tsangarides, S (Blackwell Publishing, 2006-09)
    We present results of an analysis of high-resolution spectra obtained with the Subaru Telescope High Dispersion Spectrograph, of two Carbon-Enhanced Metal-Poor stars, HE 1305+0007 and HE 1152-0355, and of the classical CH ...
  • High-resolution spectroscopy of extremely metal-poor stars from SDSS/SEGUE. I. Atmospheric parameters and chemical compositions 
    Aoki, W; Beers, T. C; Lee, Young Sun; Honda, S; Ito, H; Takada-Hidai, M; Frebel, A; Suda, T; Fujimoto, M. Y; Carollo, D; Sivarani, T (IOP Publishing, 2013-01)
    Chemical compositions are determined based on high-resolution spectroscopy for 137 candidate extremely metalpoor (EMP) stars selected from the Sloan Digital Sky Survey (SDSS) and its first stellar extension, the ...
  • High-resolution spectroscopy of the extremely iron-poor post-AGB star CCâLyr 
    Aoki, W; Matsuno, Tadafumi; Honda, S; Parthasarathy, M (Astronomical Society of Japan, 2017-04)
    High-resolution optical spectroscopy was conducted for the metal-poor post-AGB star CC Lyr to determine its chemical abundances and spectral line profiles. Our standard abundance analysis confirms its extremely low ...
  • Horizons: nuclear astrophysics in the 2020s and beyond 
    Schatz, H; Becerril Reyes, A. D; Best, A; Brown, E. F; Chatziioannou, K; Chipps, K. A; Deibel, C. M; Ezzeddine, R; Galloway, D. K; Hansen, C. J; Herwig, F; Gibson, B. K; Gorda, T; Gourgouliatos, K. N; Graber, V; Gupta, M; Haxton, W. C; Heger, A; Nevins, B; Hix, W. R; Ho, W. C. G; Rebeiro, B. M; Holmbeck, E. M; Hood, A. A; Huth, S; Imbriani, G; Izzard, R. G; Jain, R; Jayatissa, H; Johnston, Z; Newton, W. G; Kajino, T; Reifarth, R; Kankainen, A; Kiss, G. G; Kwiatkowski, A; La Cognata, M; Laird, A. M; Lamia, L; Landry, P; Laplace, E; Launey, K. D; Nguyen, L. Q; Richard, A. L; Leahy, D; Leckenby, G; Lennarz, A; Longfellow, B; Lovell, A. E; Lynch, W. G; Lyons, S. M; Maeda, K; Masha, E; Matei, C; Rijal, N; Nishikawa, K; Merc, J; Messer, B; Montes, F; Mukherjee, A; Nishimura, N; Nunes, F. M; O'Connor, E; O'Shea, B. W; Ji, A. P; Roederer, I. U; Ong, W. J; Pain, S. D; Pajkos, M. A; Pignatari, M; Pizzone, R. G; Placco, V. M; Plewa, T; Pritychenko, B; Psaltis, A; Puentes, D; Rojo, J. S; Lugaro, M; Qian, Y-Z; Radice, D; Rapagnani, D; J. S. K; Meisel, Z; Saito, Y; Schwenk, A; Cote, B; Sergi, M. L; Sidhu, R. S; Simon, A; Sivarani, T; Skuladottir, A; Smith, M. S; Spiridon, A; Sprouse, T. M; Norman, D; Starrfield, S; Caplan, M. E; Steiner, A. W; Strieder, F; Sultana, I; Surman, R; Szucs, T; Tawfik, A; Thielemann, F; Trache, L; Trappitsch, R; Read, J. S; Champagne, A. E; Tsang, M. B; Tumino, A; Upadhyayula, S; Valle Martínez, J. O; Van der Swaelmen, M; Viscasillas Vazquez, C; Watts, A; Wehmeyer, B; Wiescher, M; Wrede, C; Clark, J. A; Roberts, L. F; Yoon, J; Zegers, R. G. T; Zermane, M. A; Zingale, M; Spyrou, A; Timmes, F. X; Travaglio, C; Vassh, V; Abia, C; Couder, M; Adsley, P; Agarwal, S; Aliotta, M; Aoki, W; Arcones, A; Aryan, A; Bandyopadhyay, A; Banu, A; Bardayan, D. W; Barnes, J; Couture, A; Bauswein, A; Beers, T. C; Bishop, J; Boztepe, T; de Mink, S. E; Debnath, S; deBoer, R. J; den Hartogh, J; Mumpower, M. R; Denissenkov, P; Dexheimer, V; Dillmann, I; Escher, J. E; Famiano, M. A; Farmer, R; Fisher, R; Frohlich, C; Frebel, A; Fryer, C; Neto, D; Fuller, G; Ganguly, A. K; Ghosh, S (IOP Publishing, 2022-11)
    Nuclear astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper ...
  • Subaru/HDS study of CH stars: elemental abundances for stellar neutron-capture process studies 
    Goswami, A; Aoki, W; Drisya, K (Oxford University Press on behalf of the Royal Astronomical Society, 2016-01)
    A comprehensive abundance analysis providing rare insight into the chemical history of lead stars is still lacking. We present results from high-resolution (R ∼ 50 000) spectral analyses of three CH stars, HD 26, HD ...

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