Search Results - "ROEDERER, Ian U"

Finding r-II Sibling Stars in the Milky Way with the Greedy Optimistic Clustering Algorithm by Hattori, Kohei, Okuno, Akifumi, Roederer, Ian U.

“…R -process enhanced stars with [Eu/Fe] ≥ +0.7 (so-called r -II stars) are believed to have formed in an extremely neutron-rich environment in which a rare…”
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THE DIVERSE ORIGINS OF NEUTRON-CAPTURE ELEMENTS IN THE METAL-POOR STAR HD 94028: POSSIBLE DETECTION OF PRODUCTS OF i-PROCESS NUCLEOSYNTHESIS by Roederer, Ian U, Karakas, Amanda I, Pignatari, Marco, Herwig, Falk

“…We present a detailed analysis of the composition and nucleosynthetic origins of the heavy elements in the metal-poor ([Fe/H] = −1.62 ± 0.09) star HD 94028…”
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High-resolution Optical Spectroscopy of Stars in the Sylgr Stellar Stream by Roederer, Ian U., Gnedin, Oleg Y.

“…We observe two metal-poor main-sequence stars that are members of the recently discovered Sylgr stellar stream. We present radial velocities, stellar…”
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The R-process Alliance: First Release from the Southern Search for R-process-enhanced Stars in the Galactic Halo by Hansen, Terese T., Holmbeck, Erika M., Beers, Timothy C., Placco, Vinicius M., Roederer, Ian U., Frebel, Anna, Sakari, Charli M., Simon, Joshua D., Thompson, Ian B.

“…The recent detection of a binary neutron star merger and the clear evidence of the decay of radioactive material observed in this event have, after 60 years of…”
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A New Test of Copper and Zinc Abundances in Late-type Stars Using Ultraviolet Cu ii and Zn ii Lines by Roederer, Ian U., Barklem, Paul S.

“…We present new abundances derived from Cu i , Cu ii , Zn i , and Zn ii lines in six warm (5766 ≤  ≤ 6427 K), metal-poor (−2.50 ≤ [Fe/H] ≤ −0.95) dwarf and…”
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The R-Process Alliance: First Magellan/MIKE Release from the Southern Search for R-process-enhanced Stars by Ezzeddine, Rana, Rasmussen, Kaitlin, Frebel, Anna, Chiti, Anirudh, Hinojisa, Karina, Placco, Vinicius M., Ji, Alexander P., Beers, Timothy C., Hansen, Terese T., Roederer, Ian U., Sakari, Charli M., Melendez, Jorge

“…Extensive progress has recently been made in our understanding of heavy-element production via the r -process in the universe, specifically with the first…”
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GERMANIUM, ARSENIC, AND SELENIUM ABUNDANCES IN METAL-POOR STARS by Roederer, Ian U

“…The elements germanium (Ge, Z = 32), arsenic (As, Z = 33), and selenium (Se, Z = 34) span the transition from charged-particle or explosive synthesis of the…”
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Evidence for an Aspherical Population III Supernova Explosion Inferred from the Hyper-metal-poor Star HE 1327–2326 by Ezzeddine, Rana, Frebel, Anna, Roederer, Ian U., Tominaga, Nozomu, Tumlinson, Jason, Ishigaki, Miho, Nomoto, Ken’ichi, Placco, Vinicius M., Aoki, Wako

“…We present observational evidence that an aspherical supernova explosion could have occurred in the first stars in the early universe. Our results are based on…”
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Detailed abundances of 15 stars in the metal-poor globular cluster NGC 4833 by Roederer, Ian U., Thompson, Ian B.

“…We have observed 15 red giant stars in the relatively massive, metal-poor globular cluster NGC 4833 using the Magellan Inamori Kyocera Echelle spectrograph at…”
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R-process-rich Stellar Streams in the Milky Way by Gull, Maude, Frebel, Anna, Hinojosa, Karina, Roederer, Ian U., Ji, Alexander P., Brauer, Kaley

“…We present high-resolution Magellan/MIKE spectra of 22 bright (9 < V < 13.5) metal-poor stars (−3.18 < [Fe/H] < −1.37) in three different stellar streams, the…”
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HD 222925: A New Opportunity to Explore the Astrophysical and Nuclear Conditions of r-process Sites by Holmbeck, Erika M., Surman, Rebecca, Roederer, Ian U., McLaughlin, G. C., Frebel, Anna

“…With the most trans-iron elements detected of any star outside the solar system, HD 222925 represents the most complete chemical inventory among metal-poor…”
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The R-process Alliance: A Nearly Complete R-process Abundance Template Derived from Ultraviolet Spectroscopy of the R-process-enhanced Metal-poor Star HD 222925 by Roederer, Ian U., Lawler, James E., Den Hartog, Elizabeth A., Placco, Vinicius M., Surman, Rebecca, Beers, Timothy C., Ezzeddine, Rana, Frebel, Anna, Hansen, Terese T., Hattori, Kohei, Holmbeck, Erika M., Sakari, Charli M.

“…We present a nearly complete rapid neutron-capture process ( r -process) chemical inventory of the metal-poor ([Fe/H] = −1.46 ± 0.10) r -process-enhanced…”
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The R-Process Alliance: Chemodynamically Tagged Groups of Halo r-process-enhanced Stars Reveal a Shared Chemical-evolution History by Gudin, Dmitrii, Shank, Derek, Beers, Timothy C., Yuan, Zhen, Limberg, Guilherme, Roederer, Ian U., Placco, Vinicius, Holmbeck, Erika M., Dietz, Sarah, Rasmussen, Kaitlin C., Hansen, Terese T., Sakari, Charli M., Ezzeddine, Rana, Frebel, Anna

“…We derive dynamical parameters for a large sample of 446 r -process-enhanced (RPE) metal-poor stars in the halo and disk systems of the Milky Way, based on…”
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Iron and neutron-capture element abundance variations in the globular cluster M2 (NGC 7089) by Yong, David, Roederer, Ian U., Grundahl, Frank, Da Costa, Gary S., Karakas, Amanda I., Norris, John E., Aoki, Wako, Fishlock, Cherie K., Marino, A. F., Milone, A. P., Shingles, Luke J.

“…We present CN and CH indices and Ca ii triplet metallicities for 34 giant stars and chemical abundances for 33 elements in 14 giants in the globular cluster…”
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Metal Mixing in the r-process Enhanced Ultrafaint Dwarf Galaxy Reticulum II by Ji, Alexander P., Simon, Joshua D., Roederer, Ian U., Magg, Ekaterina, Frebel, Anna, Johnson, Christian I., Klessen, Ralf S., Magg, Mattis, Cescutti, Gabriele, Mateo, Mario, Bergemann, Maria, Bailey, John I.

“…The ultrafaint dwarf galaxy Reticulum II was enriched by a single rare and prolific r -process event. The r -process content of Reticulum II thus provides a…”
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The R-Process Alliance: Chemodynamically Tagged Groups. II. An Extended Sample of Halo r-process-enhanced Stars by Shank, Derek, Beers, Timothy C., Placco, Vinicius M., Gudin, Dmitrii, Catapano, Thomas, Holmbeck, Erika M., Ezzeddine, Rana, Roederer, Ian U., Sakari, Charli M., Frebel, Anna, Hansen, Terese T.

“…Orbital characteristics based on Gaia Early Data Release 3 astrometric parameters are analyzed for ∼1700 r -process-enhanced (RPE; [Eu/Fe] > +0.3) metal-poor…”
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Iron-peak Element Abundances in Warm Very Metal-poor Stars by Sneden, Christopher, Boesgaard, Ann Merchant, Cowan, John J., Roederer, Ian U., Den Hartog, Elizabeth A., Lawler, James E.

“…We have derived new detailed abundances of Mg, Ca, and the Fe-group elements Sc through Zn ( Z = 21−30) for 37 main-sequence turnoff very metal-poor stars…”
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Detailed Iron-peak Element Abundances in Three Very Metal-poor Stars by Cowan, John J., Sneden, Christopher, Roederer, Ian U., Lawler, James E., Hartog, Elizabeth A. Den, Sobeck, Jennifer S., Boesgaard, Ann Merchant

“…We have obtained new detailed abundances of the Fe-group elements Sc through Zn ( Z  = 21–30) in three very metal-poor ([Fe/H] ≈ −3) stars: BD+03 o 740, BD−13…”
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The R-Process Alliance: 2MASS J22132050–5137385, the Star with the Highest-known r-process Enhancement at [Eu/Fe] = +2.45 by Roederer, Ian U, Beers, Timothy C, Hattori, Kohei, Placco, Vinicius M, Hansen, Terese T, Ezzeddine, Rana, Frebel, Anna, Holmbeck, Erika M, Sakari, Charli M

“…We present stellar parameters and chemical abundances of 47 elements detected in the bright (V = 11.63) very metal-poor ([Fe/H] = −2.20 ± 0.12) star 2MASS…”
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Abundance Analysis of Stars at Large Radius in the Sextans Dwarf Spheroidal Galaxy by Roederer, Ian U., Pace, Andrew B., Placco, Vinicius M., Caldwell, Nelson, Koposov, Sergey E., Mateo, Mario, Olszewski, Edward W., Walker, Matthew G.

“…We present the stellar parameters and chemical abundances of 30 elements for five stars located at large radii (3.5–10.7 times the half-light radius) in the…”
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