Zobrazeno 1 - 10
of 283
pro vyhledávání: '"Roederer, Ian U."'
Autor:
Bandyopadhyay, Avrajit, Ezzeddine, Rana, Prieto, Carlos Allende, 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.
Understanding the abundance pattern of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial insights into the chemical evolution of the Milky Way, revealing primary sites and major sources of
Externí odkaz:
http://arxiv.org/abs/2408.03731
Autor:
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 J22132050-5137385. We observed this star using the Magellan Inamori Kyocera Echelle spectrogra
Externí odkaz:
http://arxiv.org/abs/2406.02691
Autor:
Garcia, Jonathan Cabrera, Sakari, Charli M., Roederer, Ian U., Evans, Donavon W., Silva, Pedro, Mateo, Mario, Song, Ying-Yi, Kremin, Anthony, Bailey III, John I., Walker, Matthew G.
M15 is a globular cluster with a known spread in neutron-capture elements. This paper presents abundances of neutron-capture elements for 62 stars in M15. Spectra were obtained with the Michigan/Magellan Fiber System (M2FS) spectrograph, covering a w
Externí odkaz:
http://arxiv.org/abs/2403.00063
Autor:
Shah, Shivani P., Ezzeddine, Rana, Roederer, Ian U., Hansen, Terese T., Placco, Vinicius M., Beers, Timothy C., Frebel, Anna, Ji, Alexander P., Holmbeck, Erika, Marshall, Jennifer, Sakari, Charli M.
We present a detailed chemical-abundance analysis of a highly $r$-process enhanced (RPE) star, 2MASS J00512646-1053170, using high-resolution spectroscopic observations with $Hubble\ Space\ Telescope$/STIS in the UV and Magellan/MIKE in the optical.
Externí odkaz:
http://arxiv.org/abs/2401.12311
Autor:
Walker, Matthew G., Caldwell, Nelson, Mateo, Mario, Olszewski, Edward W., Pace, Andrew B., Bailey III, John I., Koposov, Sergey E., Roederer, Ian U.
Publikováno v:
The Astrophysical Journal Supplement Series, 2023, Volume 268, Issue 1, id.19, 40 pp
We present spectroscopic data for 16369 stellar targets within and/or toward 38 dwarf spheroidal galaxies and faint star clusters within the Milky Way halo environment. All spectra come from observations with the multi-object, fiber-fed echelle spect
Externí odkaz:
http://arxiv.org/abs/2312.12738
Autor:
Roederer, Ian U., Vassh, Nicole, Holmbeck, Erika M., Mumpower, Matthew R., Surman, Rebecca, Cowan, John J., Beers, Timothy C., Ezzeddine, Rana, Frebel, Anna, Hansen, Terese T., Placco, Vinicius M., Sakari, Charli M.
Publikováno v:
Science, 382, 1177-1180 (2023)
The heaviest chemical elements are naturally produced by the rapid neutron-capture process (r-process) during neutron star mergers or supernovae. The r-process production of elements heavier than uranium (transuranic nuclei) is poorly understood and
Externí odkaz:
http://arxiv.org/abs/2312.06844
Autor:
Placco, Vinicius M., Almeida-Fernandes, Felipe, Holmbeck, Erika M., Roederer, Ian U., Mardini, Mohammad K., Hayes, Christian R., Venn, Kim, Chiboucas, Kristin, Deibert, Emily, Gamen, Roberto, Heo, Jeong-Eun, Jeong, Miji, Kalari, Venu, Martioli, Eder, Xu, Siyi, Diaz, Ruben, Gomez-Jimenez, Manuel, Henderson, David, Prado, Pablo, Quiroz, Carlos, Ruiz-Carmona, Roque, Simpson, Chris, Urrutia, Cristian, McConnachie, Alan W., Pazder, John, Burley, Gregory, Ireland, Michael, Waller, Fletcher, Berg, Trystyn A. M., Robertson, J. Gordon, Hartman, Zachary, Jones, David O., Labrie, Kathleen, Perez, Gabriel, Ridgway, Susan, Thomas-Osip, Joanna
We report on the chemo-dynamical analysis of SPLUS J142445.34-254247.1, an extremely metal-poor halo star enhanced in elements formed by the rapid neutron-capture process. This star was first selected as a metal-poor candidate from its narrow-band S-
Externí odkaz:
http://arxiv.org/abs/2310.17024
Autor:
Roederer, Ian U., Pace, Andrew B., Placco, Vinicius M., Caldwell, Nelson, Koposov, Sergey E., Mateo, Mario, Olszewski, Edward W., Walker, Matthew G.
We present 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 Sextans dwarf spheroidal galaxy. We selected these stars using proper motions, radial velocities,
Externí odkaz:
http://arxiv.org/abs/2307.02585
Autor:
Pace, Andrew B., Koposov, Sergey E., Walker, Matthew G., Caldwell, Nelson, Mateo, Mario, Olszewski, Edward W., Roederer, Ian U., Bailey III, John I., Belokurov, Vasily, Kuehn, Kyler, Li, Ting S., Zucker, Daniel B.
We present Magellan/M2FS spectroscopy of four recently discovered Milky Way star clusters (Gran 3/Patchick~125, Gran 4, Garro 01, LP 866) and two newly discovered open clusters (Gaia 9, Gaia 10) at low Galactic latitudes. We measure line-of-sight vel
Externí odkaz:
http://arxiv.org/abs/2304.06904
Autor:
Sneden, Christopher, Boesgaard, Ann Merchant, Cowan, John J., Roederer, Ian U., Hartog, Elizabeth A. Den, 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 ([Fe/H] <= -2.1). We analyzed Keck HIRES optical and near-UV high signal-to-noise spectra origin
Externí odkaz:
http://arxiv.org/abs/2304.06899