TY - JOUR
T1 - SPLUS J142445.34-254247.1
T2 - an r-process-enhanced, actinide-boost, extremely metal-poor star observed with GHOST
AU - Placco, Vinicius M.
AU - Almeida-Fernandes, Felipe
AU - Holmbeck, Erika M.
AU - Roederer, Ian U.
AU - Mardini, Mohammad K.
AU - Hayes, Christian R.
AU - Venn, Kim
AU - Chiboucas, Kristin
AU - Deibert, Emily
AU - Gamen, Roberto
AU - Heo, Jeong-Eun
AU - Jeong, Miji
AU - Kalari, Venu
AU - Martioli, Eder
AU - Xu, Siyi
AU - Diaz, Ruben
AU - Gomez-Jimenez, Manuel
AU - Henderson, David
AU - Prado, Pablo
AU - Quiroz, Carlos
AU - Ruiz-Carmona, Roque
AU - Simpson, Chris
AU - Urrutia, Cristian
AU - McConnachie, Alan W.
AU - Pazder, John
AU - Burley, Gregory
AU - Ireland, Michael
AU - Waller, Fletcher
AU - Berg, Trystyn A. M.
AU - Robertson, J. Gordon
AU - Hartman, Zachary
AU - Jones, David O.
AU - Labrie, Kathleen
AU - Perez, Gabriel
AU - Ridgway, Susan
AU - Thomas-Osip, Joanna
N1 - Copyright the Author(s) 2023. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.
PY - 2023/12/10
Y1 - 2023/12/10
N2 - We report on a chemo-dynamical analysis of SPLUS J142445.34−254247.1 (SPLUS J1424−2542), an extremely metal-poor halo star enhanced in elements formed by the rapid neutron-capture process (r-process). This star was first selected as a metal-poor candidate from its narrowband S-PLUS photometry and followed up spectroscopically in medium resolution with Gemini-South/GMOS, which confirmed its low-metallicity status. High-resolution spectroscopy was gathered with GHOST at Gemini-South, allowing for the determination of the chemical abundances for 36 elements, from carbon to thorium. At [Fe/H] = −3.39, SPLUS J1424−2542 is one of the lowest-metallicity stars with measured Th and has the highest log ϵ ( Th / Eu ) observed to date, making it part of the “actinide-boost” category of r-process-enhanced stars. The analysis presented here suggests that the gas cloud from which SPLUS J1424−2542 formed must have been enriched by at least two progenitor populations. The light-element (Z ≤ 30) abundance pattern is consistent with the yields from a supernova explosion of metal-free stars with 11.3-13.4 M ⊙, and the heavy-element (Z ≥ 38) abundance pattern can be reproduced by the yields from a neutron star merger (1.66 M ⊙ and 1.27 M ⊙) event. A kinematical analysis also reveals that SPLUS J1424−2542 is a low-mass, old halo star with a likely in situ origin, not associated with any known early merger events in the Milky Way.
AB - We report on a chemo-dynamical analysis of SPLUS J142445.34−254247.1 (SPLUS J1424−2542), an extremely metal-poor halo star enhanced in elements formed by the rapid neutron-capture process (r-process). This star was first selected as a metal-poor candidate from its narrowband S-PLUS photometry and followed up spectroscopically in medium resolution with Gemini-South/GMOS, which confirmed its low-metallicity status. High-resolution spectroscopy was gathered with GHOST at Gemini-South, allowing for the determination of the chemical abundances for 36 elements, from carbon to thorium. At [Fe/H] = −3.39, SPLUS J1424−2542 is one of the lowest-metallicity stars with measured Th and has the highest log ϵ ( Th / Eu ) observed to date, making it part of the “actinide-boost” category of r-process-enhanced stars. The analysis presented here suggests that the gas cloud from which SPLUS J1424−2542 formed must have been enriched by at least two progenitor populations. The light-element (Z ≤ 30) abundance pattern is consistent with the yields from a supernova explosion of metal-free stars with 11.3-13.4 M ⊙, and the heavy-element (Z ≥ 38) abundance pattern can be reproduced by the yields from a neutron star merger (1.66 M ⊙ and 1.27 M ⊙) event. A kinematical analysis also reveals that SPLUS J1424−2542 is a low-mass, old halo star with a likely in situ origin, not associated with any known early merger events in the Milky Way.
UR - http://www.scopus.com/inward/record.url?scp=85180089434&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/ad077e
DO - 10.3847/1538-4357/ad077e
M3 - Article
AN - SCOPUS:85180089434
SN - 0004-637X
VL - 959
SP - 1
EP - 17
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 60
ER -