Supergiant Stars as Tracers of Galactic Chemical Composition

Ferro, A. Arellano; Parrao, L.; Mantegazza, L.

doi:10.1007/978-94-011-0125-7_42

Cited by 7 publications

(13 citation statements)

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“…A much smaller reddening is cited for HD 18391 by Arellano Ferro & Parrao (1990), who tabulated, but did not use, a value of E B−V = 0.56 by Schmidt (1984) for the reddening of the double cluster h and χ Persei. That value is clearly much too small according to the study of HD 18391's surroundings made by Turner et al (2009a), and would lead to an intrinsic B-V color for the super- giant almost a half magnitude redder than expected for a G0 Ia star lying off the blue edge of the instability strip (see Turner et al 2009a).…”

Section: Discussionmentioning

confidence: 99%

The Distance Scale for Classical Cepheid Variables

Turner

Burke

2002

The Astronomical Journal

117

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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 reddening-independent indices, photometry on the Lick six-color system, Strömgren system, Walraven system, Washington system, Cape BVI system, DDO system, and Geneva system, IRSB studies, and Cepheid spectroscopy, both old and new. Reddenings tied to period-color relations are the least reliable, as expected, while photometric color excesses vary in precision, their accuracy depending on the methodology and calibration sample. The tests provide insights into the accuracy and precision of published Cepheid reddening scales, and lead to a new system of standardized reddenings comprising a sample of 198 variables with an average uncertainty of ±0.028 in E B−V , the precision being less than ±0.01 for many. The collected color excesses are used to map the dispersion in intrinsic colors as a function of pulsation period, the results contradicting current perceptions about the period dependence of dispersion in Cepheid effective temperatures.

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Section: Discussionmentioning

confidence: 99%

The Distance Scale for Classical Cepheid Variables

Turner

Burke

2002

The Astronomical Journal

117

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“…References. 1 Crawford (1975); Fabregat & Reglero (1990);Ferro et al (1990); Gronbech & Olsen (1976, 1977; Olsen (1977Olsen ( , 1983Olsen ( , 1993Olsen ( , 1994a; Olsen & Perry (1984); Perry et al (1987); Reglero & Fabregat (1991); Schuster & Nissen (1988);Twarog (1980). Figure 2 shows two examples of synthetic spectra of the C 2 molecular band regions around λ5128 and λ5165, and of the C atomic lines at λ5052.2 and λ5380.3 for the sunlight spectrum reflected by Ganymede (second observation run) and for the metal-rich star HD 160691.…”

Section: Carbon Abundance From Spectral Synthesismentioning

confidence: 99%

Accurate and homogeneous abundance patterns in solar-type stars of the solar neighbourhood: a chemo-chronological analysis

Silva

Mello

Milone

et al. 2012

A&A

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Aims. We report the derivation of abundances of C, Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd, and Sm in a sample of 25 solar-type stars of the solar neighbourhood, correlating the abundances with the stellar ages, kinematics, and orbital parameters. Methods. The spectroscopic analysis, based on data of high resolution and high signal-to-noise ratio, was differential to the Sun and applied to atomic line equivalent widths supplemented by the spectral synthesis of C and C 2 features. We also performed a statistical study by using the method of tree clustering analysis, searching for groups of stars sharing similar elemental abundance patterns. We derived the stellar parameters from various criteria, with average errors of 30 K, 0.13 dex, and 0.05 dex, respectively, for T eff , log g, and [Fe/H]. The average error of the [X/Fe] abundance ratios is 0.06 dex. Ages were derived from theoretical HR diagrams and membership of the stars in known kinematical moving groups.

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“…Tables 1−3 and 5 are only available in electronic form at http://www.aanda.org RM05a; Twarog et al 2007;Holmberg et al 2007) and giants (e.g. Bond 1980;Arellano Ferro & Mantegazza 1996;Hilker 2000;Ramírez & Meléndez 2004;Calamida et al 2007Calamida et al , 2009, as reviewed by Árnadóttir et al (2010). The evolutionary stage of stars can be determined using the c 1 index together with other uvby color indices (e.g.…”

Section: Introductionmentioning

confidence: 99%

uvby–βphotometry of solar twins

Meléndez¹,

Schuster²,

Silva³

et al. 2010

A&A

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Aims. Solar colors have been determined on the uvby-β photometric system to test absolute solar fluxes, to examine colors predicted by model atmospheres as a function of stellar parameters (T eff , log g, [Fe/H]), and to probe zero-points of T eff and metallicity scales. Methods. New uvby-β photometry is presented for 73 solar-twin candidates. Most stars of our sample have also been observed spectroscopically to obtain accurate stellar parameters. Using the stars that most closely resemble the Sun, and complementing our data with photometry available in the literature, the solar colors on the uvby-β system have been inferred. Our solar colors are compared with synthetic solar colors computed from absolute solar spectra and from the latest Kurucz (ATLAS9) and MARCS model atmospheres. The zero-points of different T eff and metallicity scales are verified and corrections are proposed. Results. Our solar colors are (b − y) = 0.4105 ± 0.0015, m 1, = 0.2122 ± 0.0018, c 1, = 0.3319 ± 0.0054, and β = 2.5915 ± 0.0024. The (b − y) and m 1, colors obtained from absolute spectrophotometry of the Sun agree within 3-σ with the solar colors derived here when the photometric zero-points are determined from either the STIS HST observations of Vega or an ATLAS9 Vega model, but the c 1, and β synthetic colors inferred from absolute solar spectra agree with our solar colors only when the zero-points based on the ATLAS9 model are adopted. The Kurucz solar model provides a better fit to our observations than the MARCS model. For photometric values computed from the Kurucz models, (b − y) and m 1, are in excellent agreement with our solar colors independently of the adopted zero-points, but for c 1, and β agreement is found only when adopting the ATLAS9 zero-points. The c 1, color computed from both the Kurucz and MARCS models is the most discrepant, probably revealing problems either with the models or observations in the u band. The T eff calibration of Alonso and collaborators has the poorest performance (∼140 K off), while the relation of Casagrande and collaborators is the most accurate (within 10 K). We confirm that the Ramírez & Meléndez uvby metallicity calibration, recommended by Árnadóttir and collaborators to obtain [Fe/H] in F, G, and K dwarfs, needs a small (∼10%) zero-point correction to place the stars and the Sun on the same metallicity scale. Finally, we confirm that the c 1 index in solar analogs has a strong metallicity sensitivity.

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Supergiant Stars as Tracers of Galactic Chemical Composition

Cited by 7 publications

References 0 publications

The Distance Scale for Classical Cepheid Variables

The Distance Scale for Classical Cepheid Variables

Accurate and homogeneous abundance patterns in solar-type stars of the solar neighbourhood: a chemo-chronological analysis

uvby–βphotometry of solar twins

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