Results 91 to 100 of about 158,293 (319)
Detection of Fluorine in the Halo Planetary Nebula BoBn 1: Evidence For a Binary Progenitor Star
, 2008 We have found the fluorine lines [F IV] 3996.92A,4059.90A in the extremely metal-poor ([Ar/H] = -2.10+/-0.21) halo planetary nebula (PN) BoBn 1 in high-dispersion spectra from the 8.2-m VLT/UVES archive.
Acker +22 more
core +1 more source
Advanced Engineering Materials, EarlyView.Al–Si alloys are particularly in demand for automotive and electronic applications, thanks to their excellent wear and thermal properties. Nevertheless, when processed by conventional methods with low cooling rates, the coarse primary Si phases are responsible for increasing brittleness and inducing crack propagation.
Layla Shams Tisha +3 more
wiley +1 more source
The Extremely Metal-rich Knot of Stars at the Heart of the Galaxy
The Astrophysical JournalWe show with Gaia XP spectroscopy that extremely metal-rich (EMR) stars in the Milky Way ([M/H] _XP ≳ 0.5) are largely confined to a tight “knot” at the center of the Galaxy. This EMR knot is round in projection, has a fairly abrupt edge near R _GC,proj ∼
Hans-Walter Rix +17 more
doaj +1 more source
Vibrational Instability of Metal-Poor Low-Mass Main-Sequence Stars
, 2012 We find that low-degree low-order g-modes become unstable in metal-poor low-mass stars due to the $\varepsilon$-mechanism of the pp-chain. Since the outer convection zone of these stars is limited only to the very outer layers, the uncertainty in the ...
A. Boury +11 more
core +1 more source
High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey [PDF]
, 2015 The SkyMapper Southern Sky Survey is carrying out a search for the most metal-poor stars in the Galaxy. It identifies candidates by way of its unique filter set that allows for estimation of stellar atmospheric parameters.
Asplund, Martin +15 more
core +2 more sources
Advanced Engineering Materials, EarlyView.This study investigates the bond quality of co‐extruded aluminum–titanium hybrid profiles, focusing on the lateral angular co‐extrusion (LACE) process. It examines how heat treatments (HT) affect intermetallic phase formation, bond strength, and material properties.
Norman Mohnfeld +9 more
wiley +1 more source
Formation of WNL Stars in the MW and LMC Based on the k − ω Model
The Astrophysical JournalWe adopt a set of second-order differential equations ( k − ω model) to handle core convective overshooting in massive stars, simulate the evolution of nitrogen sequence Wolf–Rayet (WNL) stars with different metallicities and initial masses, both ...
Jijuan Si, Zhi Li, Yan Li
doaj +1 more source
S-process in low-mass extremely metal-poor stars
EPJ Web of Conferences, 2012 We present post-processing s-process calculations for the core He-flash of a 1M☉ star with and Z = 10−8. Our model shows neutron densities larger than 1014cm−3, resulting in the production of s-process elements. The model reproduces the C, O, Sr, and Ba
Weiss A., Serenelli A., Cruz M.A.
doaj +1 more source
Iron-peak Element Abundances in Warm Very Metal-poor Stars
The Astrophysical Journal, 2023 We have derived new detailed abundances of Mg, Ca, and the Fe-group elements Sc through Zn ( Z = 21−30) for 37 main-sequence turnoff very metal-poor stars ([Fe/H] ≲−2.1).
Christopher Sneden +5 more
doaj +1 more source
Advanced Engineering Materials, EarlyView.Hydrostatic bearings excel in high‐precision applications, but their performance hinges on a continuous external supply. This study evaluates various material combinations for sliding surfaces to mitigate damage during supply failures or misalignment and to discover the most effective materials identified for enhancing the reliability and efficiency of
Michal Michalec +6 more
wiley +1 more source