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Sensitive limits on the water abundance in cold low-mass molecular cores
formation submil
2014/12/26
We present Submillimeter Wave Astronomy Satellite observations of water vapor in two cold starless clouds, B68 and core D in ρ Ophiuchi. Sensitive nondetections of the 110-101 transition of o-H2O are ...
Chandra Detection of Fe XVII in Absorption: Iron Abundance in the Hot Gaseous Interstellar Medium
4U 1820–303 abundances
2014/12/24
The iron depletion level and the gas-phase iron abundance in the hot (~106 K) interstellar medium (ISM) are critical to our understanding of its energy balance as well as the thermal sputtering, cooli...
Testing Subhalo Abundance Matching in Cosmological Smoothed Particle Hydrodynamics Simulations
galaxies satellite galaxies
2014/12/22
Subhalo abundance matching (SHAM) is a technique for populating simulated dark matter distributions with galaxies, assuming a monotonic relation between a galaxy's stellar mass or luminosity and the m...
Elemental abundance differences in the 16 Cygni binary system: a signature of gas giant planet formation?
Elemental abundance differences signature planet formation
2011/10/20
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. Abunda...
Revision of the 15N(p,γ)16O reaction rate and oxygen abundance in H-burning zones
physical data processes: nuclear reactions abundances
2011/10/13
The NO cycle takes place in the deepest layer of a H-burning core or shell, when the temperature exceeds T {\simeq} 30 {\cdot} 106 K. The O depletion observed in some globular cluster giant stars, alw...
A Chemical Abundance Study of 10 Open Clusters Based on WIYN-Hydra Spectroscopy
Chemical Abundance Study Clusters Based WIYN-Hydra Spectroscopy
2011/10/12
We present a detailed chemical abundance study of evolved stars in 10 open clusters based on Hydra multi-object echelle spectra obtained with the WIYN 3.5m telescope. From an analysis of both equivale...
Chemical abundance analysis of the Open Clusters Berkeley 32, NGC 752, Hyades and Praesepe
Stars: abundances – Galaxy: disc – Galaxy: open clusters and associations: individual: NGC 752 Hyades Berkeley 32 Preasepe (M 44)
2011/10/8
Context. Open clusters are ideal test particles to study the chemical evolution of the Galactic disc. However the existing high-resolution abundance determinations, not only of [Fe/H], but also of oth...
The First Fluorine Abundance Determinations in Extragalactic AGB Carbon Stars
FluorineAbundance Determinations Extragalactic
2011/9/29
Fluorine (19F) abundances (or upper limits) are derived in six extragalactic AGB carbon stars from the HF(1-0) R9 line at 2.3358 mu in high resolution spectra. The stars belong to the Local Group gala...
An abundance study of red-giant-branch stars in the Hercules dwarf spheroidal galaxy
red-giant-branch stars the Hercules dwarf spheroidal galaxy
2011/1/11
Using high-resolution spectroscopy, we provide a determination of [Fe/H] and [Ca/H] for confirmed red-giant branch member stars of the Hercules dwarf spheroidal galaxy. Based on this we explore the ag...
The chemical abundances of metal-poor stars are an excellent test bed by which to set new constraints on models of neutron-capture processes at low metallicity. Some r-process-rich (hereafter r-rich) ...
Effects of rotation and magnetic fields on the lithium abundance and asteroseismic properties of exoplanet-host stars
magnetic fields the lithium abundance asteroseismic properties
2011/1/11
Aims: The effects of rotation and magnetic fields on the surface abundances of solar-type stars are studied in order to investigate whether the reported difference in lithium content of exoplanet-host...
The chemical composition of the Orion star-forming region: II. Stars, gas, and dust: the abundance discrepancy conundrum
the Orion star-forming region II. Stars
2011/1/13
We re-examine the recombination/collisional emission line (RL/CEL) nebular abundance discrepancy problem in the light of recent high-quality abundance determinations in young stars in the Orion star-f...
As one of the most powerful probes of cosmological structure formation, the abundance of massive galaxy clusters is a sensitive probe of modifications to gravity on cosmological scales. In this paper,...
Spectroscopic observations of a sample of dwarf spiral galaxies. II- Abundance gradients
dwarf spiral galaxies Abundance gradients
2010/11/10
The oxygen gradient of four dS galaxies has been determined using abundances for several
Hii regions determined with four different methods. The gradient slopes of the three non-barred
galaxies in t...
The Elemental Abundance Distributions of Milky Way Satellite Galaxies
Elemental Abundance Distributions Milky Way Satellite Galaxies
2010/11/11
The chemical compositions of the stars in Milky Way (MW)satellite galaxies reveals the history of gas flows and star formation (SF)intensity. This talk presented a Keck/DEIMOS spectroscopic survey of ...