Search Results - "Hansen, Terese T."

The Lanthanide Fraction Distribution in Metal-poor Stars: A Test of Neutron Star Mergers as the Dominant r-process Site by Ji, Alexander P., Drout, Maria R., Hansen, Terese T.

“…Multimessenger observations of the neutron star merger GW170817 and its kilonova proved that neutron star mergers can synthesize large quantities of r-process…”
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Chemical Abundances in the Ultra-faint Dwarf Galaxies Grus I and Triangulum II: Neutron-capture Elements as a Defining Feature of the Faintest Dwarfs by Ji, Alexander P., Simon, Joshua D., Frebel, Anna, Venn, Kim A., Hansen, Terese T.

“…Abstract We present high-resolution spectroscopy of four stars in two candidate ultra-faint dwarf galaxies (UFDs), Grus I (Gru I) and Triangulum II (Tri II)…”
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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.

“…Abstract 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…”
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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

“…Abstract Extensive progress has recently been made in our understanding of heavy-element production via the r -process in the universe, specifically with the…”
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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.

“…Abstract We present a nearly complete rapid neutron-capture process ( r -process) chemical inventory of the metal-poor ([Fe/H] = −1.46 ± 0.10) r…”
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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

“…Abstract 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,…”
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Kinematics of Antlia 2 and Crater 2 from the Southern Stellar Stream Spectroscopic Survey (S 5) by Ji, Alexander P., Koposov, Sergey E., Li, Ting S., Erkal, Denis, Pace, Andrew B., Simon, Joshua D., Belokurov, Vasily, Cullinane, Lara R., Da Costa, Gary S., Kuehn, Kyler, Lewis, Geraint F., Mackey, Dougal, Shipp, Nora, Simpson, Jeffrey D., Zucker, Daniel B., Hansen, Terese T., Bland-Hawthorn, Joss

“…Abstract We present new spectroscopic observations of the diffuse Milky Way satellite galaxies Antlia 2 and Crater 2, taken as part of the Southern Stellar…”
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RAVE J203843.2–002333: The First Highly R-process-enhanced Star Identified in the RAVE Survey by Placco, Vinicius M., Holmbeck, Erika M., Frebel, Anna, Beers, Timothy C., Surman, Rebecca A., Ji, Alexander P., Ezzeddine, Rana, Points, Sean D., Kaleida, Catherine C., Hansen, Terese T., Sakari, Charli M., Casey, Andrew R.

“…Abstract We report the discovery of RAVE J203843.2−002333, a bright ( V = 12.73), very metal-poor ( = −2.91), r -process-enhanced ( = +1.64 and = −0.81) star…”
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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.

“…Abstract Orbital characteristics based on Gaia Early Data Release 3 astrometric parameters are analyzed for ∼1700 r -process-enhanced (RPE; [Eu/Fe] > +0.3)…”
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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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Chemical Diversity on Small Scales: Abundance Analysis of the Tucana V Ultrafaint Dwarf Galaxy by Hansen, Terese T., Simon, Joshua D., Li, Ting S., Sharkey, Domani, Ji, Alexander P., Thompson, Ian B., Reggiani, Henrique M., Galarza, Jhon Yana

“…The growing number of Milky Way satellites detected in recent years has introduced a new focus for stellar abundance analysis. Abundances of stars in…”
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Discovery of a Metal-poor Red Giant Star with the Highest Ultralithium Enhancement by Kowkabany, Jeremy, Ezzeddine, Rana, Charbonnel, Corinne, Roederer, Ian U., Wang, Ella Xi, Li, Yangyang, Hackshaw, Zoe, Beers, Timothy C., Frebel, Anna, Hansen, Terese T., Holmbeck, Erika, Placco, Vinicius M., Sakari, Charli M.

“…Abstract We present the discovery of 2MASS J05241392−0336543 (hereafter J0524−0336), a very metal-poor ([Fe/H] = −2.43 ± 0.16), highly r -process-enhanced…”
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The R-Process Alliance: Abundance Universality among Some Elements at and between the First and Second R-Process Peaks by Roederer, Ian U., Cowan, John J., Pignatari, Marco, Beers, Timothy C., Den Hartog, Elizabeth A., Ezzeddine, Rana, Frebel, Anna, Hansen, Terese T., Holmbeck, Erika M., Mumpower, Matthew R., Placco, Vinicius M., Sakari, Charli M., Surman, Rebecca, Vassh, Nicole

“…Abstract We present new observational benchmarks of rapid neutron-capture process ( r -process) nucleosynthesis for elements at and between the first ( A ∼ 80)…”
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The R-Process Alliance: Chemical Abundances for a Trio of r-process-enhanced Stars—One Strong, One Moderate, and One Mild by Cain, Madelyn, Frebel, Anna, Gull, Maude, Ji, Alexander P., Placco, Vinicius M., Beers, Timothy C., Meléndez, Jorge, Ezzeddine, Rana, Casey, Andrew R., Hansen, Terese T., Roederer, Ian U., Sakari, Charli

“…Abstract We present detailed chemical abundances of three new bright ( V ∼ 11), extremely metal-poor ([Fe/H] ∼ −3.0), r -process-enhanced halo red giants based…”
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Uranium Abundances and Ages of r-process Enhanced Stars with Novel U ii Lines by Shah, Shivani P., Ezzeddine, Rana, Ji, Alexander P., Hansen, Terese T., Roederer, Ian U., Catelan, Márcio, Hackshaw, Zoe, Holmbeck, Erika M., Beers, Timothy C., Surman, Rebecca

“…Abstract The ages of the oldest stars shed light on the birth, chemical enrichment, and chemical evolution of the universe. Nucleocosmochronometry provides an…”
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The R-process Alliance: Fifth Data Release from the Search for R-process-enhanced Metal-poor Stars in the Galactic Halo with the GTC by Bandyopadhyay, Avrajit, Ezzeddine, Rana, Allende Prieto, Carlos, Aria, Nima, Shah, Shivani P., Beers, Timothy C., Frebel, Anna, Hansen, Terese T., Holmbeck, Erika M., Placco, Vinicius M., Roederer, Ian U., Sakari, Charli M.

“…Abstract Understanding the abundance pattern of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial…”
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The R-Process Alliance: Spectroscopic Follow-up of Low-metallicity Star Candidates from the Best & Brightest Survey by Placco, Vinicius M., Santucci, Rafael M., Beers, Timothy C., Chanamé, Julio, Sepúlveda, María Paz, Coronado, Johanna, Rossi, Silvia, Lee, Young Sun, Starkenburg, Else, Youakim, Kris, Barrientos, Manuel, Ezzeddine, Rana, Frebel, Anna, Hansen, Terese T., Holmbeck, Erika M., Ji, Alexander P., Rasmussen, Kaitlin C., Roederer, Ian U., Sakari, Charli M., Whitten, Devin D.

“…We present results from an observing campaign to identify low-metallicity stars in the Best & Brightest Survey. From medium-resolution (R ∼ 1200-2000)…”
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S5: The Destruction of a Bright Dwarf Galaxy as Revealed by the Chemistry of the Indus Stellar Stream by Hansen, Terese T, Ji, Alexander P, Da Costa, Gary S, Li, Ting S, Casey, Andrew R, Pace, Andrew B, Cullinane, Lara R, Erkal, Denis, Koposov, Sergey E, Kuehn, Kyler, Lewis, Geraint F, Mackey, Dougal, Simpson, Jeffrey D, Shipp, Nora, Zucker, Daniel B, Bland-Hawthorn, Joss

“…The recently discovered Indus stellar stream exhibits a diverse chemical signature compared to what is found for most other streams due to the abundances of…”
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OBSERVATIONAL CONSTRAINTS ON FIRST-STAR NUCLEOSYNTHESIS. I. EVIDENCE FOR MULTIPLE PROGENITORS OF CEMP-NO STARS by Yoon, Jinmi, Beers, Timothy C., Placco, Vinicius M., Rasmussen, Kaitlin C., Carollo, Daniela, He, Siyu, Hansen, Terese T., Roederer, Ian U., Zeanah, Jeff

“…ABSTRACT We investigate anew the distribution of absolute carbon abundance, A(C) = log ϵ(C), for carbon-enhanced metal-poor (CEMP) stars in the halo of the…”
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Chemical Abundance Signature of J0023+0307: A Second-generation Main-sequence Star with [Fe/H] < −6 by Frebel, Anna, Ji, Alexander P., Ezzeddine, Rana, Hansen, Terese T., Chiti, Anirudh, Thompson, Ian B., Merle, Thibault

“…Abstract We present a chemical abundance analysis of the faint halo metal-poor main-sequence star J0023+0307, with [Fe/H] < −6.3, based on a high-resolution (…”
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