51 citations · 494 across the 33 of their papers we have counts for
34 papers
Chemo-dynamical Analysis of a CNO-Enhanced Ultra Metal-poor Star (): Insights into Early Enrichment by Faint Population III Supernova
Guilherme Limberg, Vinicius M. Placco, Alexander P. Ji +10
We report an independent identification of the ultra metal-poor (UMP) star () DR3 $\texttt{source_id}$ 4795913112968206720 (GDR3_479591) in the miss…
Sr and Ba yields of the First Generation(s) of stars: Constraints from metal-poor stars
Sarah Hughes, Anna Frebel, Xiaowei Ou +6
We present our chemical abundance analysis of ten new extremely metal-poor stars with $-4.05\leq\mbox{[Fe/H]}\leq-2.33$, based on high-resolution (R ) Magellan/MIKE spe…
Carbon Abundances in Metal-Poor Stars Reveal Distinct Galaxy and Star Formation Pathways in the Early Universe
Alexander Yelland, Anna Frebel, Xiaowei Ou +2
Carbon-enhanced metal-poor (CEMP; with and ) stars preserve information about early chemical enrichment, low-mass star formation, and th…
The \emph{R}-process Alliance: A Bright, Strongly \emph{R}-process-enhanced Extremely Metal-poor Star Observed with GHOST
Mohammad K. Mardini, Anna Frebel, Vinicius M. Placco +8
We present a detailed chemical-abundance and kinematic analysis of four extremely metal-poor (EMP; [Fe/H] ) stars identified from \textit{Gaia} BP/RP data in our ongoing…
The -Process Alliance: Actinide Abundances, Variation, and Evolution in Metal-Poor Stars
Shivani P. Shah, Rana Ezzeddine, Erika M. Holmbeck +11
The actinides, including thorium (Th), are the heaviest observable elements synthesized in the universe, holding clues to the extremes of the astrophysical and nuclear conditions o…
Galactic Archaeology with the Subaru `Ōnohi`ula Prime Focus Spectrograph Strategic Program
Masashi Chiba, Rosemary F. G. Wyse, Evan N. Kirby +48
The recently commissioned Subaru `Ōnohi`ula Prime Focus Spectrograph (PFS) will obtain spectra from nearly 2,400 fibers that cover 1.24 square degrees. The 360 night Subaru Strateg…
TOI-7169 b: A Hot Jupiter Transiting a Metal-Poor Star
Joshua D. Simon, Joseph E. Rodriguez, Jhon Yana Galarza +38
Most known planets are found around metal-rich host stars, which has made it difficult to determine whether a lower metallicity limit for planet formation exists and how the proper…
Discovery of an Star in XP Spectra
Guilherme Limberg, Vinicius M. Placco, Alexander P. Ji +5
We report on the discovery of GDR3_526285 ( DR3 Source ID 5262850721755411072), a star with and one of the lowest metal ($\text{atomic number} >…
Exploring the Formation Mechanisms of Double Neutron Star Systems: An Analytical Perspective
Ali Taani, Mohammed Abu-Saleem, Mohammad Mardini +2
Double Neutron Stars (DNSs) are unique probes to study various aspects of modern astrophysics. Recent discoveries have confirmed direct connections between DNSs and supernova explo…
Early r-process Enrichment and Hierarchical Assembly Across the Sagittarius Dwarf Galaxy
Xiaowei Ou, Alexander Yelland, Anirudh Chiti +3
Dwarf galaxies like Sagittarius (Sgr) provide a unique window into the early stages of galactic chemical evolution, particularly through their metal-poor stars. By studying the che…
Cosmological insights into the early accretion of r-process-enhanced stars II. Dynamical identification of lost members of Reticulum II
P. Berczik, M. Ishchenko, O. Sobodar +1
Aims. We identify the possible dynamical connection between individual r-process-enhanced stars and the ultra-faint dwarf galaxy Reticulum II based on the current phase-space infor…
The oldest stars with low neutron-capture element abundances and origins in ancient dwarf galaxies
Hillary Diane Andales, Ananda Santos Figueiredo, Casey Gordon Fienberg +2
We present a detailed chemical abundance and kinematic analysis of six extremely metal-poor ( [Fe/H] 2.9) halo stars with very low neutron-capture abundances ([Sr…
Signatures of tidal disruption of the Hercules ultra-faint dwarf galaxy
Xiaowei Ou, Anirudh Chiti, Nora Shipp +6
The Hercules ultra-faint dwarf galaxy (UFD) has long been hypothesized to be tidally disrupting, yet no conclusive evidence has been found for tidal disruption owing partly to diff…
A Strontium-rich Ultra Metal-poor Star in the Atari Disk Component
Mohammad K. Mardini, Anna Frebel, Anirudh Chiti
We report on the discovery of the first ultra metal-poor (UMP) star 2MASS~J205001946613298 (J20506613; \mbox{[Fe/H] = }) selected from the Gaia BP/RP spectral catalog…
Unraveling the Origins and Development of the Galactic Disk through Metal-Poor Stars
Maria Rah, Manolya Yatman, Ali Taani +2
The Milky Way is a spiral galaxy comprising three main components: the Bulge, the Disk, and the Halo. Of particular interest is the Galactic disk, which holds a significant portion…
Enrichment by Extragalactic First Stars in the Large Magellanic Cloud
Anirudh Chiti, Mohammad Mardini, Guilherme Limberg +8
The Large Magellanic Cloud (LMC) is the Milky Way's most massive satellite galaxy, which only recently (~2 billion years ago) fell into our Galaxy. Since stellar atmospheres preser…
Candidate Members of the VMP/EMP Disk System of the Galaxy from the SkyMapper and SAGES Surveys
Jihye Hong, Timothy C. Beers, Young Sun Lee +15
Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target-selec…
SPLUS J142445.34-254247.1: An R-Process Enhanced, Actinide-Boost, Extremely Metal-Poor star observed with GHOST
Vinicius M. Placco, Felipe Almeida-Fernandes, Erika M. Holmbeck +33
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 sta…
Metal-poor stars observed with the Magellan Telescope. IV. Neutron-capture element signatures in 27 main-sequence stars
Mohammad K. Mardini, Anna Frebel, Leyatt Betre +3
Based on high-resolution spectra obtained with Magellan/MIKE, we present a chemo-dynamical analysis for 27 near main-sequence turnoff metal-poor stars, including 20 stars analyzed…
Chemo-Dynamically Tagged Groups of CEMP Stars in the Halo of the Milky Way. I. Untangling the Origins of CEMP- and CEMP-no Stars
Joseph Zepeda, Timothy C. Beers, Vinicius M. Placco +7
We construct a sample of 644 carbon-enhanced metal-poor (CEMP) stars with abundance analyses based on moderate- to high-resolution spectroscopic studies. Dynamical parameters for t…
The chemical abundance pattern of the extremely metal-poor thin disk star 2MASS J1808-5104 and its origins
Mohammad K. Mardini, Anna Frebel, Rana Ezzeddine +6
We present a high-resolution (), high signal-to-noise () Magellan/MIKE spectrum of the bright extremely metal-poor star 2MASS~J18085104. We find [Fe/H] = $…
Possibilities and Limitations of Kinematically Identifying Stars from Accreted Ultra-Faint Dwarf Galaxies
Kaley Brauer, Hillary Diane Andales, Alexander P. Ji +4
The Milky Way has accreted many ultra-faint dwarf galaxies (UFDs), and stars from these galaxies can be found throughout our Galaxy today. Studying these stars provides insight int…
The Atari Disk, a Metal-Poor Stellar Population in the Disk System of the Milky Way
Mohammad K. Mardini, Anna Frebel, Anirudh Chiti +3
We have developed a chemo-dynamical approach to assign 36,010 metal-poor SkyMapper stars to various Galactic stellar populations. Using two independent techniques (velocity and act…
Detailed chemical abundances of stars in the outskirts of the Tucana II ultra-faint dwarf galaxy
Anirudh Chiti, Anna Frebel, Alexander P. Ji +6
We present chemical abundances and velocities of five stars between 0.3 kpc to 1.1 kpc from the center of the Tucana II ultra-faint dwarf galaxy (UFD) from high-resolution Magellan…