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Related papers: Iron abundance in HII regions

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The abundance of iron is measured from emission line complexes at 6.65 keV (Fe line) and 8 keV (Fe/Ni line) in {\em RHESSI} X-ray spectra during solar flares. Spectra during long-duration flares with steady declines were selected, with an…

Solar and Stellar Astrophysics · Physics 2015-06-03 K. J. H. Phillips , B. R. Dennis

We present the first attempt to determine the iron abundance in hot central stars of planetary nebulae. We perform an analysis with fully metal-line blanketed NLTE model atmospheres for a sample of ten stars (T_eff >= 70.000 K) for which…

Astrophysics · Physics 2007-05-23 J. L. Deetjen , S. Dreizler , T. Rauch , K. Werner

The solar photospheric Fe abundance has been determined using realistic ab initio 3D, time-dependent, hydrodynamical model atmospheres. The study is based on the excellent agreement between the predicted and observed line profiles directly…

Astrophysics · Physics 2007-05-23 M. Asplund , AA. Nordlund , R. Trampedach , R. F. Stein

We have collected from different surveys some significant spectroscopic data observed from star-forming galaxies in the local Universe. The objects showing a relatively rich spectrum in number of lines from different elements were selected…

Astrophysics of Galaxies · Physics 2022-01-19 Marcella Contini

NLTE line formation calculations of FeI in the solar atmosphere are extended to include weak optical lines. Previously established atomic models are used to discriminate between different ways of treating collisional interaction processes.…

Astrophysics · Physics 2009-11-07 T. Gehren , A. J. Korn , J. Shi

We present measurements of [Fe/H] for six M supergiant stars and three giant stars within 0.5 pc of the Galactic Center (GC) and one M supergiant star within 30 pc of the GC. The results are based on high-resolution (lambda / Delta lambda…

We present a new iron abundance analysis of the hyper metal-poor star HE$~$1327-2326, based on Fe II lines detected in its UV spectral range for the first time. In a Cosmic Origins Spectrograph (COS) spectrum, five new Fe II lines could be…

Solar and Stellar Astrophysics · Physics 2018-08-27 Rana Ezzeddine , Anna Frebel

We present high signal-to-noise spectrophotometric observations of seven luminous HII galaxies. The observations have been made with the use of a double-arm spectrograph which provides spectra with a wide wavelength coverage, from 3400 to…

It has been suggested in the literature that the (Fe/alpha) abundance ratio may be used as a chronometer, due to a delay in this ratio reaching its solar value as predicted by galactic chemical evolution models. Using grids of…

Astrophysics · Physics 2007-05-23 Kirk Korista , Nalaka Kodituwakku , Michael Corbin , Wolfram Freudling

We combine UV spectra obtained with the HST/GHRS echelle, IMAPS, and Copernicus to study the abundances and physical conditions in the predominantly ionized gas seen at high (-105 to -65 km/s) and intermediate velocities (-60 to -10 km/s)…

Astrophysics · Physics 2008-11-26 D. E. Welty , E. B. Jenkins , J. C. Raymond , C. Mallouris , D. G. York

We investigate the chemical abundances of NGC3603 in the Milky Way, of 30Doradus in the Large Magellanic Cloud, and of N66 in the Small Magellanic Cloud. Mid-infrared observations with the Infrared Spectrograph onboard the Spitzer Space…

We present spectroscopic observations of a sample of 72 emission-line objects, including mainly HII regions, in the spiral galaxy M 33. Spectra were obtained with the multi-object, wide field spectrograph AF2/WYFFOS at the 4.2m WHT…

Astrophysics · Physics 2009-11-13 L. Magrini , J. M. Vilchez , A. Mampaso , R. L. M. Corradi , P. Leisy

We present the [OIII]52{\mu}m map of the dwarf galaxy IC10, obtained with the Field-Imaging Far-Infrared Line Spectrometer (FIFI-LS) on board the Stratospheric Observatory for Infrared Astronomy (SOFIA). We combine the [OIII]52{\mu}m map…

Astrophysics of Galaxies · Physics 2024-07-09 F. L. Polles , D. Fadda , W. D. Vacca , N. P. Abel , M. Chevance , C. Fischer , J. M. Jackson , V. Lebouteiller , S. Madden , L. Ramambason

The role of optical Fe III absorption lines in B-type stars as iron abundance diagnostics is considered. To date, ultraviolet Fe lines have been widely used in B-type stars, although line blending can severely hinder their diagnostic power.…

Analysis of RHESSI 3--10 keV spectra for 27 solar flares is reported. This energy range includes thermal free--free and free--bound continuum and two line features, at 6.7keV and 8keV, principally due to highly ionized iron (Fe). We used…

Astrophysics · Physics 2011-02-11 K. J. H. Phillips , C. Chifor , B. R. Dennis

We describe a new method for determining total gas-phase abundances for the Galactic ISM with minimal ionization uncertainties. For sight lines toward globular clusters containing both UV-bright stars and radio pulsars, one can measure…

Astrophysics · Physics 2009-11-13 J. Christopher Howk , Kenneth R. Sembach , Blair D. Savage

From equivalent widths of the SI lines at 8694 A, Israelian & Rebolo (2001) and Takada-Hidai et al. (2002) have derived a surprisingly high sulphur-to-iron ratio ([S/Fe] = 0.5 to 0.7) in six halo stars with [Fe/H] ~ -2.0 suggesting perhaps…

Astrophysics · Physics 2007-05-23 P. E. Nissen , Y. Q. Chen , M. Asplund , M. Pettini

We study the physical and chemical properties of a sample of HII regions located at RG >11 kpc and present the radial distribution of abundances towards the Galaxy anticentre. We carried out optical spectroscopic observations of nine HII…

Astrophysics of Galaxies · Physics 2017-01-18 Alba Fernández-Martín , Enrique Pérez-Montero , José Manuel Vílchez , Antonio Mampaso

Infrared OH lines at 1.55 - 1.56 um in the H-band were obtained with the Phoenix high-resolution spectrograph at the 2.1m telescope of the Kitt Peak National Observatory for a sample of 14 metal-poor stars. Detailed analyses of the sample…

Astrophysics · Physics 2011-02-11 Jorge Melendez , Beatriz Barbuy , Francois Spite

We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni and Ba for 43 metal-poor field stars in the solar neighbourhood with iron abundances [Fe/H] ranging from -0.4 to -3.0. Total abundance errors are estimated to about…