Results 21 to 30 of about 63,717 (277)

Beryllium abundances along the evolutionary sequence of the open cluster IC 4651 - New test for hydrodynamical stellar models

, 2009
[abridged] Previous analyses of lithium abundances in main sequence and red giant stars have revealed the action of mixing mechanisms other than convection in stellar interiors.
C. Charbonnel, L. Pasquini, N. Lagarde, Pasquini, Randich, Rodolfo Smiljanic, Sestito, Smiljanic, Talon   +8 more
core   +2 more sources

Multiple Stellar Populations at Less Evolved Stages. III. A Possible Helium Spread in NGC 2210

The Astrophysical Journal, 2023
Helium variations are common features of globular clusters (GCs) with multiple stellar populations. All the formation scenarios predict that secondary population stars are enhanced in helium, but the exact helium content depends on the polluters ...
Chengyuan Li, Xin Ji, Long Wang, Yue Wang, Baitian Tang, Antonino P. Milone, Yujiao Yang, Holger Baumgardt, Dengkai Jiang   +8 more
doaj   +1 more source

Observable Signatures of Planet Accretion in Red Giant Stars I: Rapid Rotation and Light Element Replenishment

, 2012
The orbital angular momentum of a close-orbiting giant planet can be sufficiently large that, if transferred to the envelope of the host star during the red giant branch (RGB) evolution, it can spin-up the star's rotation to unusually large speeds.
Alexander, Balachandran, Bard, Bard, Bizyaev, Blackwell, Blackwell, Blackwell, Blackwell, Blackwell, Blaise, Boothroyd, Busso, Butler, Böhm-Vitense, Carlberg, Carlberg, Carlberg, Carlberg, Carney, Castelli, Castilho, Chanamé, Charbonnel, Charbonnel, da Silva, Davis, de Medeiros, de Medeiros, Denissenkov, Denissenkov, Drake, Duquennoy, Eggleton, Frink, Fuhr, Fulbright, Ghezzi, Glebocki, Gratton, Griffin, Griffin, Hinkle, Houdashelt, Høg, Joleen K. Carlberg, Katia Cunha, Kumar, Kumar, Kurucz, Kurucz, Kurucz, Kurucz, Kurucz, Lodders, Majewski, Mandell, Massarotti, Mitchell, Mousis, Nordhaus, Palmerini, Paxton, Pilachowski, Piskunov, Raassen, Rabl, Raghavan, Reddy, Reddy, Ruchti, Sackmann, Sato, Schlegel, Shetrone, Smith, Smith, Sneden, Steven R. Majewski, Strassmeier, Uesugi, Verne V. Smith, Vogt, Wasserburg   +83 more
core   +1 more source

On the Galactic chemical evolution of sulphur. Sulphur abundances from the [S i] 1082 nm line in giants [PDF]

, 2013
Context. The Galactic chemical evolution of sulphur is still under debate. At low metallicities some studies find no correlation between [S/Fe] and [Fe/H], others find [S/Fe] increasing towards lower metallicities, and still others find a combination of ...
Dupree, A. K., Matrozis, E., Ryde, N.
core   +1 more source

Revealing the structure of land plant photosystem II: the journey from negative‐stain EM to cryo‐EM

FEBS Letters, EarlyView.
Advances in cryo‐EM have revealed the detailed structure of Photosystem II, a key protein complex driving photosynthesis. This review traces the journey from early low‐resolution images to high‐resolution models, highlighting how these discoveries deepen our understanding of light harvesting and energy conversion in plants.
Roman Kouřil
wiley   +1 more source

A Systematic NLTE Study of Very Metal-poor Stars with Metallicity down to −4.3 dex. I. Global Stellar Parameters Based on High-resolution Spectra

The Astrophysical Journal
Very metal-poor (VMP) stars provide a record of the chemical composition and dynamics of the early Galaxy. Based on the high-resolution and high signal-to-noise ratio spectra from the Subaru Telescope for 103 VMP stars, in this series of papers we ...
Jianrong Shi, Gang Zhao, Shuai Liu, Zeming Zhou, Haining Li, Hongliang Yan, Sofya Alexeeva, Huawei Zhang, Wako Aoki, Tadafumi Matsuno, Jingkun Zhao, Huiling Chen, Yufu Shen   +12 more
doaj   +1 more source

Multiple Populations in Star Clusters

Universe, 2022
We review the multiple population (MP) phenomenon of globular clusters (GCs): i.e., the evidence that GCs typically host groups of stars with different elemental abundances and/or distinct sequences in photometric diagrams.
Antonino P. Milone, Anna F. Marino
doaj   +1 more source

Mapping the evolution of mitochondrial complex I through structural variation

FEBS Letters, EarlyView.
Respiratory complex I (CI) is crucial for bioenergetic metabolism in many prokaryotes and eukaryotes. It is composed of a conserved set of core subunits and additional accessory subunits that vary depending on the organism. Here, we categorize CI subunits from available structures to map the evolution of CI across eukaryotes. Respiratory complex I (CI)
Dong‐Woo Shin, Tingting Chen, James A. Letts   +2 more
wiley   +1 more source

Plasmodium falciparum gametogenesis essential protein 1 (GEP1) is a transmission‐blocking target

FEBS Letters, EarlyView.
This study shows Plasmodium falciparum GEP1 is vital for activating sexual stages of malarial parasites even independently of a mosquito factor. Knockout parasites completely fail gamete formation even when a phosphodiesterase inhibitor is added. Two single‐nucleotide polymorphisms (V241L and S263P) are found in 12%–20% of field samples.
Frederik Huppertz, Milagros Siebeck Caturelli, Lina S. Lehmann, Florian Kurth, Alexander G. Maier, Kai Matuschewski   +5 more
wiley   +1 more source

The Interaction Between Accretion from the Interstellar Medium and Accretion from the Evolved Binary Component in Barium Stars [PDF]

Journal of Astronomy and Space Sciences, 2018
The reanalysis of the previously published abundance pattern of mild barium star HD202109 (ζ Cyg) and the chemical compositions of 129 thin disk barium stars facilitated the search for possible correlations of different stellar parameters with second ...
Yeuncheol Jeong, Alexander V. Yushchenko, Dmytry N. Doikov   +2 more
doaj   +1 more source