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The chemical abundances of metal-poor stars provide a great deal of information regarding the individual nucleosynthetic processes that created the observed elements and the overall process of chemical enrichment of the galaxy since the…

Astrophysics of Galaxies · Physics 2015-06-17 Heather R. Jacobson , Anna Frebel

In typical astrophysical environments, the abundance of heavy elements ranges from 0.001 to 2 times the solar concentration. Lower abundances have been seen in select stars in the Milky Way's halo and in two quasar absorption systems at…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-05 Robert A. Simcoe , Peter W. Sullivan , Kathy L. Cooksey , Melodie M. Kao , Michael S. Matejek , Adam J. Burgasser

We investigate stellar elemental abundance patterns at z = 0 in 8 low-mass (M_* = 10^6 - 10^9 M_sun) galaxies in the Feedback in Realistic Environments (FIRE-2) cosmological simulations. Using magnesium (Mg) as a representative…

The damped Lyman alpha systems seen in the spectra of high redshift QSOs offer the means to determine element abundances in galaxies observed while still at an early stage of evolution. Such measurements, which have only recently come…

Astrophysics · Physics 2016-08-30 Max Pettini , Keith Lipman , Richard W. Hunstead

The past few years have seen a steady progress in the determination of element abundances at high redshifts, with new and more accurate measures of metallicities in star-forming galaxies, in QSO absorbers, and in the intergalactic medium.…

Astrophysics · Physics 2007-05-23 Max Pettini

The atmospheric parameters of the components of the 16Cygni binary system, in which the secondary has a gas giant planet detected, are measured accurately using high quality observational data. Abundances relative to solar are obtained for…

Solar and Stellar Astrophysics · Physics 2015-05-30 I. Ramirez , J. Melendez , D. Cornejo , I. U. Roederer , J. R. Fish

The elements germanium (Ge, Z=32), arsenic (As, Z=33), and selenium (Se, Z=34) span the transition from charged-particle or explosive synthesis of the iron-group elements to neutron-capture synthesis of heavier elements. Among these three…

Solar and Stellar Astrophysics · Physics 2015-06-05 Ian U. Roederer

An element's astrophysical origin should be reflected in the spatial distribution of its abundance, yielding measurably different spatial distributions for elements with different nucleosynthetic sites. However, most extragalactic…

(Abbreviated) From six spectra of high-z QSOs, we select eleven metal-rich, Z>=Z_solar, and optically-thin to the ionizing radiation, N(HI)<10^17 cm^-2, absorption systems ranging between z=1.5 and z=2.9 and revealing lines of different…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 S. A. Levshakov , I. I. Agafonova , P. Molaro , D. Reimers , J. L. Hou

Ground- and space-based observations of stellar heavy element abundances are providing a clearer picture of the chemical evolution of the Galaxy. A large number of (r)apid and (s)low neutron capture process elements, including the first…

Astrophysics · Physics 2007-05-23 John J Cowan , Christopher Sneden , James W Truran , Debra L Burris

Metal-poor stars provide the fossil record of Galactic chemical evolution and the nucleosynthesis processes that took place at the earliest times in the history of our Galaxy. From detailed abundance studies of low mass, extremely…

Solar and Stellar Astrophysics · Physics 2015-03-11 T. Hansen , C. J. Hansen , N. Christlieb , D. Yong , T. C. Beers , J. Andersen

The element boron belongs, together with lithium and beryllium, to a known trio of important elements for the study of evolutionary processes in low mass stars. Because B is the least fragile of this trio to be destroyed in the stellar…

Solar and Stellar Astrophysics · Physics 2019-12-02 N. A. Drake , R. de la Reza , V. V. Smith , K. Cunha

We report the discovery of a unique collection of metal-poor giant-stars, that exhibit anomalously high levels of $^{28}$Si, clearly above typical Galactic levels. Our sample spans a narrow range of metallicities, peaking at $-1.07\pm…

The heavy elements formed by neutron capture processes have an interesting history from which we can extract useful clues to and constraints upon both the characteristics of the processes themselves and the star formation and…

Astrophysics · Physics 2009-11-07 J. W. Truran , J. J. Cowan , C. A. Pilachowski , C. Sneden

A broad array of interstellar absorption features that appear in the ultraviolet spectra of bright sources allows us to measure the abundances and ionization states of many important heavy elements that exist as free atoms in the…

Astrophysics · Physics 2007-05-23 Edward B. Jenkins

We present preliminary results of a detailed chemical abundance analysis for a sample of solar-type stars known to exhibit excess infrared emission associated with dusty debris disks. Our sample of 28 stars was selected based on results…

Solar and Stellar Astrophysics · Physics 2015-06-17 Adam M. Ritchey , Guillermo Gonzalez , Myra Stone , George Wallerstein

The horizon for studies of element abundances has expanded dramatically in the last ten years. Once the domain of astronomers concerned chiefly with stars and nearby galaxies, this field has now become a key component of observational…

Astrophysics · Physics 2007-05-23 Max Pettini

We present new observations of copper and zinc abundances in 90 metal-poor stars, belonging to the metallicity range -3< [Fe/H] < -0.5. The present study is based on high resolution spectroscopic measurements collected at the Haute Provence…

Astrophysics · Physics 2009-11-07 T. V. Mishenina , V. V. Kovtyukh , C. Soubiran , C. Travaglio , M. Busso

We explore the elemental abundance features of metal-rich disk stars, highlighting the comparisons made with those of the recently revealed Galactic bulge stars. A similarity between two of the comparisons leads to a new theoretical picture…

Astrophysics · Physics 2009-11-13 Takuji Tsujimoto

The determination of heavy element abundances from planetary nebula (PN) spectra provides an exciting opportunity to study the nucleosynthesis occurring in the progenitor asymptotic giant branch (AGB) star. We perform post-processing…

Solar and Stellar Astrophysics · Physics 2015-05-14 Amanda I. Karakas , Maria Lugaro
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