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Related papers: New attempts to understand nanodiamond stardust

200 papers

We have observed 15 red giant stars in the relatively massive, metal-poor globular cluster NGC 4833 using the Magellan Inamori Kyocera Echelle spectrograph at Magellan. We calculate stellar parameters for each star and perform a standard…

Solar and Stellar Astrophysics · Physics 2015-06-24 Ian U. Roederer , Ian B. Thompson

We present NLTE Li abundances for 88 stars in the metallicity range -3.5 < [Fe/H] < -1.0. The effective temperatures are based on the infrared flux method with improved E(B-V) values obtained mostly from interstellar NaI D lines. The Li…

Solar and Stellar Astrophysics · Physics 2015-05-19 Jorge Melendez , Luca Casagrande , Ivan Ramirez , Martin Asplund , William Schuster

We separately assess elemental abundances in AGNs' broad and narrow emission line regions (BLR and NLR), based on a critical assessment of published results together with new photoionization models. We find 1) He/H enhancements in some AGN,…

Astrophysics of Galaxies · Physics 2023-08-31 Jiamu Huang , Douglas N. C. Lin , Gregory Shields

Barium stars are s-process enriched giants. They owe their chemical peculiarities to a past mass transfer phase. During which they were polluted by their binary companion, which at the time was an AGB star, but is now an extinct white…

Solar and Stellar Astrophysics · Physics 2018-10-10 D. Karinkuzhi , S. Van Eck , A. Jorissen , S. Goriely , L. Siess , T. Merle , A. Escorza , M. Van der Swaelmen , H. M. J. Boffin , T. Masseron , S. Shetye , B. Plez

(Abridged) The stellar sites and the complete mechanism of r-process nucleosynthesis are still unresolved issues. From consideration of the observed abundances in metal-poor stars, it is proposed that the production of the heavy r-process…

Astrophysics · Physics 2009-11-07 Y. -Z. Qian , G. J. Wasserburg

In this work the synthesis and characterization of novel gold-nanodiamond nanoparticles was performed. The synthesis was based on the reduction of gold onto the different types of nanodiamond (annealed or annealed and oxidized, 50 or 230…

This work describes a study of elemental abundances for 30 metal-poor stars whose chemical abundances provide excellent information for setting constraints on models of neutron-capture processes. Based on the abundances of main r- and weak…

Solar and Stellar Astrophysics · Physics 2015-06-12 Hongjie Li , Xiaojing Shen , Shuai Liang , Wenyuan Cui , Bo Zhang

To understand the origin of the abundance peculiarities of non-magnetic A-type stars, we present the first detailed chemical abundance analysis of a metallic line star HD 23193 (A2m) and an A-type subgiant HD 170920 (A5) which could have…

Solar and Stellar Astrophysics · Physics 2018-01-15 Tolgahan Kılıçoğlu , Şeyma Çalışkan , Kübraözge Ünal

The cosmic origin of the elements heavier than iron has long been uncertain. Theoretical modelling shows that the matter that is expelled in the violent merger of two neutron stars can assemble into heavy elements such as gold and platinum…

High Energy Astrophysical Phenomena · Physics 2017-10-17 Daniel Kasen , Brian Metzger , Jennifer Barnes , Eliot Quataert , Enrico Ramirez-Ruiz

We investigate hydrodynamical and nucleosynthetic properties of the jet-induced explosion of a population III $40M_\odot$ star and compare the abundance patterns of the yields with those of the metal-poor stars. We conclude that (1) the…

Astrophysics · Physics 2009-11-13 Nozomu Tominaga , Hideyuki Umeda , Keiichi Maeda , Nobuyuki Iwamoto , Ken'ichi Nomoto

Isotopic substitution of boron and carbon is applied for the identification of the vibrational modes of heavily boron-doped diamond synthesized by high-pressure high-temperature technique. None of the bands in the Raman spectra are shifting…

Materials Science · Physics 2008-01-11 I. I. Vlasov , E. A. Ekimov , A. A. Basov , E. Goovaerts , A. V. Zoteev

Binary neutron star mergers are thought to be one of the dominant sites of production for rapid neutron capture elements, including platinum and gold. Since the discovery of the binary neutron star merger GW170817, and its associated…

High Energy Astrophysical Phenomena · Physics 2021-07-14 James H. Gillanders , Michael McCann , Stuart A. Sim. Stephen J. Smartt , Connor P. Ballance

We present the isotope yields of two post-explosion, three-dimensional 15 $M_\odot$ core-collapse supernova models, 15S and 15A, and compare them to the carbon, nitrogen, silicon, aluminum, sulfur, calcium, titanium, iron, and nickel…

High Energy Astrophysical Phenomena · Physics 2021-02-17 Jack Schulte , Maitrayee Bose , Patrick A. Young , Gregory S. Vance

We present a novel approach aimed at identifying the key chemical elements to search for the (missing) descendants of very massive first stars exploding as Pair Instability Supernovae (PISN). Our simple and general method consists in a…

Astrophysics of Galaxies · Physics 2019-06-05 S. Salvadori , P. Bonifacio , E. Caffau , S. Korotin , S. Andreevsky , M. Spite , A. Skuladottir

Using the method presented in Erspamer & North (2002, Paper I hereafter), detailed abundances of 140 stars are presented. The uncertainties characteristic of this method are presented and discussed. In particular, we show that for a S/N…

Astrophysics · Physics 2009-11-07 D. Erspamer , P. North

In this paper, the controlled production of high quality metal-free diamond nanoparticles is demonstrated. Milling with tempered steel is shown to leave behind iron oxide contamination which is difficult to remove. Milling with SiN…

Fluorescent defects in non-cytotoxic diamond nanoparticles are candidates for qubits in quantum computing, optical labels in biomedical imaging and sensors in magnetometry. For each application these defects need to be optically and…

Materials Science · Physics 2009-08-26 Carlo Bradac , Torsten Gaebel , Nishen Naidoo , James R. Rabeau , Amanda S. Barnard

Following the recent abundance measurements of Mg, Al, Ca, Fe, and Ni in the black hole X-ray binary XTE J1118+480 using medium-resolution Keck II/ESI spectra of the secondary star (Gonz\'alez Hern\'andez et al. 2006), we perform a detailed…

Compilations of abundances of Strontium and Barium in extremely metal-poor stars show that an apparent cutoff is observed for [Sr/Ba] at [Fe/H]$<$-3.6 and large fluctuations for [Fe/H]$>$-3.6 with a clear upper bound depending on…

Solar and Stellar Astrophysics · Physics 2015-06-15 Wako Aoki , Takuma Suda , Richard Boyd , Toshitaka Kajino , Michael Famiano

We present a model to explain the wide range of abundances for heavy r-process elements (mass number A > 130) at low [Fe/H]. This model requires rapid star formation and/or an initial population of supermassive stars in the earliest…

Astrophysics · Physics 2009-10-31 G. J. Wasserburg , Y. -Z. Qian