Results 41 to 50 of about 426,951 (145)

Extremely Metal-Poor Asymptotic Giant Branch Stars

Universe, 2022
Little is known about the first stars, but hints on this stellar population can be derived from the peculiar chemical composition of the most metal-poor objects in the Milky Way and in resolved stellar populations of nearby galaxies.
Mario Cirillo, Luciano Piersanti, Oscar Straniero   +2 more
doaj   +1 more source

CONSTRAINTS OF THE PHYSICS OF LOW-MASS AGB STARS FROM CH AND CEMP STARS [PDF]

The Astrophysical Journal, 2016
ABSTRACT We analyze a set of published elemental abundances from a sample of CH stars which are based on high resolution spectral analysis of ELODIE and SUBARU/HDS spectra. All the elemental abundances were derived from local thermodynamic equilibrium analysis using model atmospheres, and thus they represent the largest homogeneous ...
S. Cristallo, D. Karinkuzhi, A. Goswami, L. Piersanti, D. Gobrecht   +4 more
openaire   +3 more sources

Rapidly Rotating Massive Pop III stars: A Solution for High Carbon Enrichment in CEMP-no Stars [PDF]

, 2023
Very metal-poor stars that have $[\text{Fe}/\text{H}]+0.7$) but have no enhancement of heavy elements ($[\text{Ba}/\text{Fe}]
Chiaki, Gen, K, Jeena S, Banerjee, Projjwal, Heger, Alexander   +3 more
core   +1 more source

Seeding the second star – II. CEMP star formation enriched from faint supernovae [PDF]

Monthly Notices of the Royal Astronomical Society, 2020
ABSTRACT Carbon-enhanced metal-poor (CEMP) stars are the living fossils holding records of chemical enrichment from early generations of stars. In this work, we perform a set of numerical simulations of the enrichment from a supernova (SN) of a first generation of metal-free (Pop III) star and the gravitational collapse of the enriched ...
Chiaki G., Wise J. H., Marassi S., Schneider R., Limongi M., Chieffi A.   +5 more
openaire   +2 more sources

The Barium Odd Isotope Fractions in Seven Ba Stars

Universe, 2022
Based on the spectra with high resolution and a high signal-to-noise ratio, we investigate the enrichment history of the s-process element in seven barium (Ba) stars by measuring their Ba odd isotope fraction.
Fang Wen, Wenyuan Cui, Miao Tian, Xiaoxiao Zhang, Jianrong Shi, Bo Zhang   +5 more
doaj   +1 more source

Nucleosynthesis in early rotating massive stars and chemical composition of CEMP stars [PDF]

Journal of Physics: Conference Series, 2020
Abstract The first massive stars triggered the onset of chemical evolution by releasing the first metals (elements heavier than helium) in the Universe. The nature of these stars and how the early chemical enrichment took place is still largely unknown.
Choplin, Arthur, Hirschi, Raphael
openaire   +2 more sources

Abundance of Heavy r-process Elements in CEMP-rs Stars: The Role of the i-process

The Astrophysical Journal
Carbon-enhanced metal-poor (CEMP) stars are ancient stars enriched in carbon and heavy elements. Some of these stars exhibit enhanced s -process and/or r -process elements, and hence are classified as CEMP-s, CEMP-rs, or CEMP-r.
A. M. Riyas, D. Karinkuzhi, S. Van Eck, A. Choplin, S. Goriely, L. Siess, M. V. Keerthy, A. Jorissen, T. Merle   +8 more
doaj   +1 more source

A Lambda Red Recombinase‐Assisted CRISPR/Cas9 System for Efficient and Precise Genome Editing in Agrobacterium tumefaciens

Plant Biotechnology Journal, EarlyView.
ABSTRACT Agrobacterium tumefaciens is a powerful delivery tool for plant genetic transformation and a pivotal platform for agricultural biotechnology. However, laboratory strains of Agrobacterium have remained genetically unoptimized for decades, with genome engineering hindered by inefficient, endogenous homologous recombination systems.
Minmin Zheng, Rui Liu, Wei‐Chang Huang, Zuren Li, Kai Hua   +4 more
wiley   +1 more source

A CEMP-no star in the ultra-faint dwarf galaxy Pisces II [PDF]

Astronomy & Astrophysics, 2018
Aims. A probable carbon enhanced metal-poor (CEMP) star, Pisces II 10694, was discovered recently in the ultra-faint (UFD) galaxy Pisces II. This galaxy is supposed to be very old, suspected to include dark matter, and likely formed the bulk of its stars before the reionisation of the Universe. Methods.
Spite, M., Spite, F., François, P., Bonifacio, P., Caffau, E., Salvadori, S.   +5 more
openaire   +4 more sources

Understanding exosomes in regenerative dentistry

Periodontology 2000, EarlyView.
Abstract Background Regenerative dentistry is shifting from cell‐based strategies to cell‐free biologics capable of orchestrating intricate tissue repair. Exosomes, nanosized extracellular vesicles carrying bioactive molecular payloads, have emerged as central modulators of intercellular communication.
Paras Ahmad, Anton Sculean, Richard J. Miron   +2 more
wiley   +1 more source