Zobrazeno 1 - 10
of 111
pro vyhledávání: '"Sakari, Charli M"'
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:
Monty, Stephanie, Belokurov, Vasily, Sanders, Jason L., Hansen, Terese T., Sakari, Charli M., McKenzie, Madeleine, Myeong, GyuChul, Davies, Ellot Y., Ardern-Arentsen, Anke, Massari, Davide
We combine stellar orbits with the abundances of the heavy, $r$-process element europium and the light, $\alpha$-element, silicon to separate in-situ and accreted populations in the Milky Way across all metallicities. At high orbital energy, the accr
Externí odkaz:
http://arxiv.org/abs/2405.08963
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:
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:
Roederer, Ian U., Cowan, John J., Pignatari, Marco, Beers, Timothy C., Hartog, Elizabeth A. Den, Ezzeddine, Rana, Frebel, Anna, Hansen, Terese T., Holmbeck, Erika M., Mumpower, Matthew R., Placco, Vinicius M., Sakari, Charli M., Surman, Rebecca, Vassh, Nicole
Publikováno v:
Astrophysical Journal Vol. 936, p. 84 (2022)
We present new observational benchmarks of rapid neutron-capture process (r-process) nucleosynthesis for elements at and between the first (A ~ 80) and second (A ~ 130) peaks. Our analysis is based on archival ultraviolet and optical spectroscopy of
Externí odkaz:
http://arxiv.org/abs/2210.15105
Autor:
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.
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 ([Eu/Fe]= +1.34 +- 0.10) Milky Way halo field red giant star, with an ultra high Li abundance of A(Li)(3D,
Externí odkaz:
http://arxiv.org/abs/2209.02184
Autor:
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 ${\sim} 1700$ $r$-process-enhanced (RPE; [Eu/Fe] $> +0.3$) metal-poor stars ([Fe/H] $\leq -0.8$) compiled from the $R$-Process Alliance, the GALactic A
Externí odkaz:
http://arxiv.org/abs/2208.09712