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Results from detailed spectroscopic analyses of stars hosting massive planets are employed to search for trends between abundances and condensation temperatures. The elements C, S, Na, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni and Zn are…

Astrophysics · Physics 2009-11-13 Guillermo Gonzalez

Most existing criteria derived from progenitor properties of core-collapse supernovae are not very accurate in predicting explosion outcomes. We present a novel look at identifying the explosion outcome of core-collapse supernovae using a…

Solar and Stellar Astrophysics · Physics 2022-09-28 Benny T. -H. Tsang , David Vartanyan , Adam Burrows

Using a deep (574 ks) Chandra observation of M87, the dominant galaxy of the nearby Virgo Cluster, we present the best measurements to date of the radial distribution of metals in the central intracluster medium (ICM). Our measurements,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 E. T. Million , N. Werner , A. Simionescu , S. W. Allen

Neutron(n)-capture elements (atomic number Z>30), which can be produced in planetary nebula (PN) progenitor stars via s-process nucleosynthesis, have been detected in nearly 100 PNe. This demonstrates that nebular spectroscopy is a…

Solar and Stellar Astrophysics · Physics 2015-05-30 N. C. Sterling , M. C. Witthoeft , D. A. Esteves , P. C. Stancil , A. L. D. Kilcoyne , R. C. Bilodeau , A. Aguilar

To assess long-term structural integrity under operational conditions in nuclear reactors, SS 316LN with varying nitrogen content is subjected to thermal aging for 20000 hours at 650{\deg}C. While the annealing twins and heterogeneous grain…

Room-temperature ferromagnetism is observed in (110) oriented ZnO films containing 5 at % of Sc, Ti, V, Fe, Co or Ni, but not Cr, Mn or Cu ions. There are large moments, 1.9 and 0.5 muB/atom for Co- and Ti-substituted oxides, respectively.…

Materials Science · Physics 2009-11-10 M. Venkatesan , C. B. Fitzgerald , J. G. Lunney , J. M. D. Coey

We investigate the chemical evolution of a collapsing core that starts from a hydrostatic core and finally form a low-mass protostar. New multiphase gas-grain models that include bulk diffusion and photon penetration are simulated by the…

Solar and Stellar Astrophysics · Physics 2018-12-27 Yang Lu , Qiang Chang , Yuri Aikawa

Transition-metal nanoclusters exhibit structural and electronic properties that depend on their size, often making them superior to bulk materials for heterogeneous catalysis. However, their performance can be limited by sulfur poisoning.…

Hydrodynamics and explosive nucleosynthesis in bipolar supernova explosions are examined to account for some peculiar properties of hypernovae as well as peculiar abundance patterns of metal-poor stars. The explosion is supposed to be…

Astrophysics · Physics 2009-11-07 K. Maeda , K. Nomoto

A systematic investigation has been performed by synthesis and comprehensive characterization of a series of SmFe1-xCuxAsO0.8F0.2 bulks (x = 0 to 0.2). These samples are well characterized by structural, Raman spectroscopy, microstructural,…

Type Ia supernova (SNIa) explosions synthesize a few tenths to several tenths of a solar mass, whose composition is the result of incomplete silicon burning that reaches peak temperatures of 4 GK to 5 GK. The elemental abundances are…

Solar and Stellar Astrophysics · Physics 2013-01-22 E. Bravo

Ion implantation of Fe and Mn into Al thin films was used for effective modification of Al superconductive properties. Critical temperature of the transition to superconducting state was found to decrease gradually with implanted Fe…

Materials Science · Physics 2009-11-13 Pasi Jalkanen , Vladimir Tuboltsev , Ari Virtanen , Konstantin Arutyunov , Jyrki Raisanen

We report optical absorption and photoluminescence spectra of Au, Fe, Co and Ni polycrystalline nanofilms in the UV-Vis-NIR range, featuring discrete bands resulting from transverse quantum confinement. The film thickness ranged from 1.1 to…

Mesoscale and Nanoscale Physics · Physics 2015-06-01 Igor Khmelinskii , Vladimir I. Makarov

We investigate the formation of dust grains in the ejecta of Type Ia supernovae (SNe Ia), adopting the carbon-deflagration W7 model. In the calculations of dust formation, we apply the nucleation and grain growth theory and consider the two…

Solar and Stellar Astrophysics · Physics 2015-05-28 Takaya Nozawa , Keiichi Maeda , Takashi Kozasa , Masaomi Tanaka , Ken'ichi Nomoto , Hideyuki Umeda

Recently theoretical works predict that some semiconductors (e.g. ZnO) doped with magnetic ions are diluted magnetic semiconductors (DMS). In DMS magnetic ions substitute cation sites of the host semiconductor and are coupled by free…

Materials Science · Physics 2009-07-22 Shengqiang Zhou , K. Potzger , Qingyu Xu , G. Talut , M. Lorenz , W. Skorupa , M. Helm , J. Fassbender , M. Grundmann , H. Schmidt

We have studied the chemistry of nitrogen--bearing species during the initial stages of protostellar collapse, with a view to explaining the observed longevity of N2H+ and NH3 and the high levels of deuteration of these species. We followed…

Astrophysics · Physics 2009-11-11 D. R. Flower , G. Pineau des Forets , C. M. Walmsley

Using results of nucleosynthesis calculations for theoretical core-collapse supernova models with various progenitor's masses, it is shown that abundance patterns of C, Mg, Si, Ca, and H seen in extremely metal-deficient stars with [Fe/H] <…

Astrophysics · Physics 2009-10-30 Toshikazu Shigeyama , Takuji Tsujimoto

We present a physically-motivated model involving the different processes affecting supernova dust grains as they are incorporated into the thermalized medium within young massive star clusters. The model is used to explain the near- to…

Astrophysics of Galaxies · Physics 2017-07-27 Sergio Martinez-Gonzalez , Richard Wünsch , Jan Palouš

Segregation to grain boundaries affects their cohesion, corrosion and embrittlement and plays a critical role in heterogeneous nucleation. In order to quantitatively study segregation and phase separation at grain boundaries, we derive a…

We investigate the evolution of dust formed in Population III supernovae (SNe) by considering its transport and processing by sputtering within the SN remnants (SNRs). We find that the fates of dust grains within SNRs heavily depend on…