Author
Number of items: 64.
Article
The Rotation of the halo of NGC 6822 from the radial velocities of carbon stars. (2016)
Graham Thompson,
Sean Ryan
and
Lisette Sibbons
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A three-dimensional hydrodynamical line profile analysis of iron lines and barium isotopes in HD140283. (2015)
A. J. Gallagher,
H. G. Ludwig,
Sean G. Ryan
and
W. Aoki
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Spectral classification of photometrically selected AGB candidates in NGC 6822. (2015)
L. F. Sibbons,
Sean G. Ryan,
Ralf Napiwotzki
and
G. P. Thompson
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The AGB population in IC 1613 using JHK photometry. (2015)
L. F. Sibbons,
Sean G. Ryan,
M. Irwin
and
R. Napiwotzki
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The Most Metal-Poor Stars. IV : The Two Populations with [Fe/H] <~ -3.0. (2013)
John Norris,
David Yong,
Michael Bessell,
Norbert Christlieb,
Martin Asplund,
G.F. Gilmore,
Rosemary F. G. Wyse,
Timothy Beers,
Paul Barklem,
Anna Frebel
and
Sean G. Ryan
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The Most Metal-poor Stars. I : Discovery, Data and Atmospheric Parameters. (2013)
John Norris,
Michael Bessell,
David Yong,
Norbert Christlieb,
Paul Barklem,
Martin Asplund,
Michael Murphy,
Timothy Beers,
Anna Frebel
and
Sean G. Ryan
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The Most Metal-poor Stars. II : Chemical Abundances of 190 Metal-poor Stars Including 10 New Stars with [Fe/H] <= -3.5. (2013)
David Yong,
John Norris,
Michael S. Bessell,
Martin Asplund,
Timothy C. Beers,
Paul S. Barklem,
Anna Frebel
and
Sean G. Ryan
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The Most Metal-poor Stars. III : The Metallicity Distribution Function and Carbon-enhanced Metal-poor Fraction. (2013)
David Yong,
John Norris,
Michael Bessell,
Norbert Christlieb,
Martin Asplund,
Timothy Beers,
Paul Barklem,
Anna Frebel
and
Sean G. Ryan
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The AGB population of NGC 6822 : Distribution and the C/M ratio from JHK photometry. (2012)
L. F. Sibbons,
Sean G. Ryan,
M-R.L. Cioni,
M. Irwin
and
R. Napiwotzki
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The barium isotopic fractions in five metal-poor stars. (2012)
Andrew Gallagher,
Sean G. Ryan,
Adam Hosford,
A E Garcia Perez,
W Aoki
and
S Honda
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Lithium abundances of halo dwarfs based on excitation temperatures. II : Non-local thermodynamic equilibrium. (2010)
A. Hosford,
A.E.G. Perez,
R. Collet,
Sean G. Ryan,
J.E. Norris
and
K.A. Olive
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The SALT HRS spectrograph : final design, instrument capabilities, and operational modes. (2010)
D.G. Bramall,
R. Sharples,
L. Tyas,
J. Schmoll,
P. Clark,
P. Luke,
N. Looker,
N.A. Dipper
and
Sean G. Ryan
The barium isotopic mixture for the metal-poor subgiant star HD 140283. (2010)
A.J. Gallagher,
Sean G. Ryan,
A.E. Garcia Perez
and
W. Aoki
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6Li/7Li estimates for metal-poor stars. (2009)
A.E. Garcia Perez,
W. Aoki,
S. Inoue,
Sean G. Ryan,
T.K. Suzuki
and
M. Chiba
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Lithium abundances of halo dwarfs based on excitation temperature I : Local thermodynamic equilibrium. (2009)
A. Hosford,
Sean G. Ryan,
A.E. Garcia Perez,
J.E. Norris
and
K.A. Olive
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A new sample of extremely/ultra metal-poor stars. (2008)
A. E. Garcia Perez,
N. Christlieb,
Sean G. Ryan,
T.C. Beers,
W. Aoki,
M. Asplund,
P.S. Barklem,
M.S. Bessell,
K. Eriksson,
A. Frebel,
B. Gustafsson,
A.J. Korn,
B. Nordstrom
and
J.E. Norris
Carbon-Enhanced Metal-Poor Stars. III : Main-Sequence Turn-Off Stars from the SDSS/SEGUE Sample. (2008)
W. Aoki,
T.C. Beers,
T. Sivarani,
B. Marsteller,
Y.S. Lee,
S. Honda,
J.E. Norris,
Sean G. Ryan
and
D. Carollo
Limits on Reddening and Gas-to-Dust Ratios for Seven Intermediate Redshift Damped Ly-alpha Absorbers from Diffuse Interstellar Bands. (2008)
B. Lawton,
C.W. Churchill,
B.A. York,
S.L. Ellison,
T.P. Snow,
R. Johnson,
Sean G. Ryan
and
C. Benn
Lithium isotopic abundances in old stars. (2008)
Ana Elia Garcia Perez,
Susumu Inoue,
Wako Aoki
and
Sean G. Ryan
Carbon enhanced metal-poor stars I : Chemical compositions of 26 stars. (2007)
W. Aoki,
T.C. Beers,
N. Christlieb,
J.E. Norris,
Sean G. Ryan
and
S. Tsangarides
Experimental Mg I oscillator strengths and radiative lifetimes for astrophysical applications on metal-poor stars : New data for the Mg I b triplet. (2007)
M. Aldenius,
J.D. Tanner,
S. Johansson,
H. Lundberg
and
Sean G. Ryan
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Spectroscopic studies of extremely metal-poor stars with the Subaru high dispersion spectrograph. IV : The alpha-element-enhanced metal-poor star BS16934-002. (2007)
W. Aoki,
S. Honda,
T.C. Beers,
M. Takada-Hidai,
N. Iwamoto,
N. Tominaga,
H. Umeda,
K. Nomoto,
J.E. Norris
and
Sean G. Ryan
Carbon-enhanced metal-poor stars. Osmium and iridium abundances in the neutron-capture-enhanced subgiants CS31062-050 and LP625-44. (2006)
W. Aoki,
S. Bisterzo,
R. Gallino,
T.C. Beers,
J.E. Norris,
Sean G. Ryan
and
S. Tsangarides
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A high-resolution spectral analysis of three carbon-enhanced metal-poor stars. (2006)
A. Goswami,
W. Aoki,
T.C. Beers,
N. Christlieb,
J.E. Norris,
Sean G. Ryan
and
S. Tsangarides
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Nucleosynthetic signatures of the first stars. (2005)
A. Frebel,
W. Aoki,
N. Christlieb,
H. Ando,
M. Asplund,
P.S. Barklem,
T.C. Beers,
K. Eriksson,
C. Fechner,
M.Y. Fujimoto,
S. Honda,
T. Kajino,
T. Minezaki,
K. Nomoto,
J.E. Norris,
Sean G. Ryan,
M. Takada-Hidai,
S. Tsangarides
and
Y. Yoshii
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Mg abundances in metal-poor halo stars as a tracer of early Galactic mixing. (2005)
E. Arnone,
Sean G. Ryan,
D. Argast,
J.E. Norris
and
T.C. Beers
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The Binary Frequency Among Carbon-enhanced, s-Process-rich, Metal-poor Stars. (2005)
S. Lucatello,
S. Tsangarides,
T.C. Beers,
E. Carretta,
R.G. Gratton
and
Sean G. Ryan
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Lithium abundances in halo dwarfs. (2005)
Sean G. Ryan
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The new record holder for the most iron-poor star: HE 1327−2326, a dwarf or subgiant with [Fe/H] = −5.4. (2005)
A. Frebel,
W. Aoki,
N. Christlieb,
H. Ando,
M. Asplund,
P.S. Barklem,
T.C. Beers,
K. Eriksson,
C. Fechner,
M.Y. Fujimoto,
S. Honda,
T. Kajino,
T. Minezaki,
K. Nomoto,
J.E. Norris,
Sean G. Ryan,
M. Takada-Hidai,
S. Tsangarides
and
Y. Yoshii
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The Hamburg/ESO R-process Enhanced Star survey (HERES). I : Project description and discovery of two stars with strong enhancements of neutron-capture elements. (2004)
N. Christlieb,
T.C. Beers,
P.S. Barklem,
M.S. Bessell,
V. Hill,
J. Holmberg,
A.J. Korn,
B. Marsteller,
L. Mashonkina,
Y.Z. Qian,
S. Rossi,
G.J. Wasserburg,
F.J. Zickgraf,
K.L. Kratz,
B. Nordstrom,
B. Pfeiffer,
J. Rhee
and
Sean G. Ryan
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A low upper-limit on the lithium isotope ratio in HD140283. (2004)
W. Aoki,
S. Inoue,
S. Kawanomoto,
Sean G. Ryan,
I.M. Smith,
T.K. Suzuki
and
M. Takada-Hidai
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Late stages of stellar evolution. (2004)
Sean G. Ryan
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Oxygen Overabundance in the Extremely Iron-poor Star CS 29498-043. (2004)
W. Aoki,
J.E. Norris,
Sean G. Ryan,
T.C. Beers,
N. Christlieb,
S. Tsangarides
and
H. Ando
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Spectroscopic Studies of Extremely Metal-Poor Stars with the Subaru High Dispersion Spectrograph. I. Observational Data. (2004)
S. Honda,
W. Aoki,
H. Ando,
H. Izumiura,
T. Kajino,
E. Kambe,
S. Kawanomoto,
K. Noguchi,
K. Okita,
K. Sadakane,
B. Sato,
M. Takada-Hidai,
Y. Takeda,
E. Watanabe,
T.C. Beers,
J.E. Norris
and
Sean G. Ryan
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The Detection of Low Eu Abundances in Extremely Metal-poor Stars and the Origin of r-Process Elements. (2004)
Y. Ishimaru,
S. Wanajo,
W. Aoki
and
Sean G. Ryan
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Lead and s-process elements in stars of various metallicities : AGB predictions and observations. (2004)
D. Delaude,
R. Gallino,
S. Christallo,
O. Straniero,
L. Husti
and
Sean G. Ryan
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On the binarity of carbon-enhanced, metal-poor stars. (2004)
S. Tsangarides,
Sean G. Ryan
and
T.C. Beers
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Europium Isotope Ratios in s-Process Element-enhanced Metal-poor Stars : A New probe of the 151Sm Branching. (2003)
W. Aoki,
Sean G. Ryan,
N. Iwamoto,
T.C. Beers,
J.E. Norris,
H. Ando,
T. Kajino,
G.J. Mathews
and
M.Y. Fujimoto
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Intermediate-metallicity, high-velocity stars and Galactic chemical evolution. (2003)
Sean G. Ryan
and
I.M. Smith
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Nucleosynthesis and early chemical evolution in galaxies. (2003)
S. Tsangarides,
E. Arnone
and
Sean G. Ryan
Observations of r- and s-process elements in population II stars. (2003)
Sean G. Ryan
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A Subaru/High Dispersion Spectrograph Study of Lead (Pb) Abundances in Eight s-Process Element-rich, Metal-poor Stars. (2002)
W. Aoki,
Sean G. Ryan,
J.E. Norris,
T.C. Beers,
H. Ando
and
S. Tsangarides
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Lithium 6104 A in Population II stars. (2002)
A. Ford,
R.D. Jeffries,
B. Smalley,
Sean G. Ryan,
W. Aoki,
S. Kawanomoto,
D.J. James
and
John R. Barnes
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Chemical Composition fo the Carbon-rich, Extremely Metal Poor Star CS 29498-043. (2002)
W. Aoki,
J.E. Norris,
Sean G. Ryan,
T.C. Beers
and
H. Ando
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Rapid Rotation of Ultra-Li-depleted Halo Stars and Their Association with Blue Stragglers. (2002)
Sean G. Ryan,
S. Gregory,
U. Kolb,
T.C. Beers
and
T. Kajino
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Extremely Metal-poor Stars : IX CS 22949-037 and the Role of Hypernovae. (2002)
J.E. Norris,
Sean G. Ryan,
T.C. Beers,
H. Ando
and
W. Aoki
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The Chemical Composition of Carbon-rich, very Metal Poor Stars : A New Class of Mildly Carbon Rich Objects without Excess of Neutron-Capture Elements. (2002)
W. Aoki,
J.E. Norris,
Sean G. Ryan,
T.C. Beers
and
H. Ando
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Big Bang Nucleosynthesis, Population III, and Stellar Genetics in the Galactic Halo. (2002)
Sean G. Ryan
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Extremely Metal-Poor Stars. VIII. High-Resolution, HighSignal-to-Noise Ratio Analysis of Five Stars with [Fe/H][[3.5. (2001)
J.E. Norris,
Sean G. Ryan
and
T.C. Beers
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Neutron Capture Elements in s-Process-Rich, Very Metal-Poor Stars. (2001)
W. Aoki,
Sean G. Ryan,
J.E. Norris,
T.C. Beers,
H. Ando,
N. Iwamoto,
T. Kajino,
G.J. Mathews
and
M.Y. Fujimoto
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The first detection of cobalt in a damped Lyman alpha system. (2001)
S.L. Ellison,
Sean G. Ryan
and
J.X. Prochaska
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Abundances and Evolution of Lithium in the Galactic Halo and Disk. (2001)
Sean G. Ryan,
T. Kajino,
T.C. Beers,
T.K. Suzuki,
D. Romano,
F. Matteucci
and
K. Rosolankova
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Ultra-Lithium-deficient Halo Stars and Blue Stragglers : A Common Origin? (2001)
Sean G. Ryan,
T.C. Beers,
T. Kajino
and
K. Rosolankova
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s- and r-process elements in two very metal-poor stars. (2001)
Sean G. Ryan,
W. Aoki,
L.A.J. Blake,
J.E. Norris,
T.C. Beers,
R. Gallino,
M. Busso
and
H. Ando
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Primordial Lithium and Big Bang Nucleosynthesis. (2000)
Sean G. Ryan,
T.C. Beers,
K.A. Olive,
B.D. Fields
and
J.E. Norris
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The host stars of extrasolar planets have normal lithium abundances. (2000)
Sean G. Ryan
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Beryllium Abundances in Halo Stars from Keck/HIRES Observations. (1999)
A.M. Boesgaard,
C.P. Deliyannis,
J.R. King,
Sean G. Ryan,
S. Vogt
and
T.C. Beers
Estimation of Stellar Metal Abundance. II : A Recalibration of the Ca II K Technique, and the Autocorrelation Function Method. (1999)
T.C. Beers,
S. Rossi,
J.E. Norris,
Sean G. Ryan
and
T. Shefler
The Spite Lithium Plateau: Ultrathin but Postprimordial. (1999)
Sean G. Ryan,
J.E. Norris
and
T.C. Beers
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Boron in the very metal-poor star BD-13 3442. (1998)
D.K. Duncan,
L.M. Rebull,
F. Primas,
A.M. Boesgaard,
C.P. Deliyannis,
L.M. Hobbs,
J.R. King
and
Sean G. Ryan
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