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Related papers: Cepheid Abundances: Multiphase Results and Spatial…

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The cosmological distance ladder crucially depends on classical Cepheids (with P=3-80 days), which are primary distance indicators up to 33 Mpc. Within this volume, very few SNe Ia have been calibrated through classical Cepheids, with…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-16 G. Fiorentino , G. Clementini , M. Marconi , I. Musella , A. Saha , M. Tosi , R. Contreras Ramos , F. Annibali , A. Aloisi , R. van der Marel

The atmospheric parameters and iron abundance of the Sloan Digital Sky Survey (SDSS) spectrophotometric standard star BD +17 4708 are critically examined using up-to-date Kurucz model atmospheres, LTE line formation calculations, and…

Astrophysics · Physics 2009-11-11 I. Ramirez , C. Allende Prieto , S. Redfield , D. L. Lambert

We present a reassessment of the radial abundance gradients of C, N, O, Ne, S, Cl and Ar in the Milky Way using deep spectra of 33 H II regions gathered from the literature, covering Galactocentric distances from 6 to 17 kpc. The distances…

Astrophysics of Galaxies · Physics 2020-06-10 Karla. Z. Arellano-Córdova , César Esteban , Jorge García-Rojas , J. Eduardo Méndez-Delgado

Field reddenings are summarized for 68 Cepheids from published studies and updated results presented here. The compilation forms the basis for a comparison with other published reddening scales of Cepheids, including those established from…

Solar and Stellar Astrophysics · Physics 2016-03-09 David G. Turner

Repeated imaging observations have been made of NGC 4527 with the Hubble Space Telescope between April and June 1999, over an interval of 69 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The…

We present the iron abundance and abundance ratios for 18 elements with respect to Fe in a sample of stars with a wide range in luminosity from luminous giants to stars near the turnoff in the globular cluster M5. The analyzed spectra,…

Astrophysics · Physics 2009-11-07 Solange V. Ramirez , Judith G. Cohen

The Gaia second Data Release (DR2) presents a first mapping of full-sky RR Lyrae stars and Cepheids observed by the spacecraft during the initial 22 months of science operations. The Specific Object Study (SOS) pipeline, developed to…

Spectra from MDM Observatory are used to assess Lick/IDS feature strength gradients inside the half-light radius of the compact Local Group elliptical galaxy M32. All but a few (of 24 measured) indices show a statistically significant…

Astrophysics · Physics 2009-11-10 Guy Worthey

Abundances of 18 chemical elements have been derived for 16 A (normal and chemically peculiar CP) and 5 F dwarfs members of the Pleiades open cluster in order to set constraints on evolutionary models. The abundances, rotational velocities…

Astrophysics · Physics 2009-11-13 M. Gebran , R. Monier

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…

This is the second in a series of papers in which we analyze spectra of over 400 K and M giants in Baade's Window, including most of the stars with proper motions measured by Spaenhauer et al. [AJ, 103, 297 (1992)]. In our first paper, we…

Astrophysics · Physics 2014-10-13 Elaine M. Sadler , R. Michael Rich , D. M. Terndrup

We have obtained the first high resolution spectra of individual stars in the dwarf irregular galaxy, NGC 6822. The spectra of the two A-type supergiants were obtained at the VLT and Keck Observatories, using UVES and HIRES, respectively. A…

New CCD photometry has been combined with published and unpublished earlier observations to study the three Cepheid variables in M13: V1, V2 and V6. The light curve characteristics in $B$, $V$ and $I_{\rm C}$ have been determined and the…

Solar and Stellar Astrophysics · Physics 2019-07-24 Wayne Osborn , Grzegorz Kopacki , Horace A. Smith , Barton J. Pritzl , Charles Kuehn , Mary Anderson

Using a sample of 70 924 stars from the second data release of the GALAH optical spectroscopic survey, we construct median sequences of [X/Mg] vs. [Mg/H] for 21 elements, separating the high-$\alpha$/``low-Ia'' and low-$\alpha$/``high-Ia''…

Solar and Stellar Astrophysics · Physics 2020-01-08 Emily Griffith , Jennifer A. Johnson , David H. Weinberg

We report new CHARA/MIRC interferometric observations of the Cepheid archetype $\delta$ Cep, which aimed at detecting the newly discovered spectroscopic companion. We reached a maximum dynamic range $\Delta H $ = 6.4, 5.8, and 5.2 mag,…

The debate on the oxygen abundances of metal-poor stars has its origin in contradictory results obtained using different abundance indicators. To achieve a better understanding of the problem we have acquired high quality spectra with the…

Astrophysics · Physics 2016-08-16 A. E. García Pérez , M. Asplund , F. Primas , P. E. Nissen , B. Gustafsson

Using standard 1D-LTE model atmosphere analysis, we provide an in-depth investigation of iron abundance as derived from neutral and singly ionization iron lines (Fe {\scriptsize{I, II}}) in nearby star clusters. Specifically, we replicate…

Solar and Stellar Astrophysics · Physics 2017-09-06 Patrick D. Aleo , Alexander C. Sobotka , Ivan Ramirez

The time behaviour of the radial abundance gradients in the galactic disk is investigated on the basis of four different samples of planetary nebulae, comprising both smaller, homogeneous sets of data, and larger, albeit non-homogeneous…

Astrophysics · Physics 2007-05-23 W. J. Maciel , L. G. Lago , R. D. D. Costa

We develop a statistical method for using multicolor photometry to determine distances using Cepheid variables including the effects of temperature, extinction, and metallicity and apply it to UBVRIJHK photometry of 694 Cepheids in 17…

Astrophysics · Physics 2009-10-30 C. S. Kochanek