scholarly journals Investigation of the Double-mode Cepheid TU Cas: Atmospheric Parameters and Chemical Composition

1993 ◽  
Vol 139 ◽  
pp. 382-382
Author(s):  
S. M. Andrievsky ◽  
V. V. Kovtyukh ◽  
E. N. Makarenko ◽  
I. A. Usenko
Keyword(s):  
Chemical Composition ◽  
Southern Hemisphere ◽  
Open Cluster ◽  
Atmospheric Parameters

AbstractAtmospheric parameters and abundances of 25 elements were determined from two spectrograms of TU Cas (with dispersion 9 Å/mm) obtained in 1977 and 1990. We find Teff= 5860 - 6000K; logg = 1.0 - 1.5; and vt = 2.9 - 5.3 km/s.The value of [Fe/H] ∼ -0.5 testifies to the fact that TU Cas is deficient in metals compared with other double-mode Cepheids. More exact values of [Fe/H] for 9 double-mode Cepheids in the Southern Hemisphere (Barrell 1982), V367 Set (a member of the open cluster NGC 6649) and our value for TU Cas all show a good correlation with P1/P0. As the atmospheric Fe abundance increases, the ratio P1/P0 decreases.Our measured values for abundances (in brackets) of various elements in the atmosphere of TU Cas are: C (8.26), Na (6.32), Mg (7.07), Si (6.85), S (6.96), Ca (5.88), Sc (2.71), Ti (4.34), V (3.35), Cr (5.29), Mn (4.92), Fe (6.94), Co (4.47), Ni (5.70), Zn (3.63), Sr (2.00), Y (2.17), Zr (2.21), Ba (1.41), La (1.08), Ce (0.96), Nd (0.82), Sm (0.42), Eu (1.04), and Gd (0.92).

scholarly journals Abundances of seven red giants in the open cluster NGC 3114

2009 ◽  
Vol 5 (S266) ◽  
pp. 495-498
Author(s):  
C. B. Pereira ◽  
C. Quireza
Keyword(s):  
Chemical Composition ◽  
Chemical Analysis ◽  
Galactic Disk ◽  
Open Cluster ◽  
Open Clusters ◽  
Red Giants ◽  
The Sun ◽  
Atmospheric Parameters ◽  
Red Giant ◽  
Good Agreement

AbstractWe present a chemical analysis of seven red giants in the open cluster NGC 3114. Our main goal is to investigate the chemical composition of this cluster, which is not yet available in the literature. We employed the FEROS spectrograph on the ESO 2.2m telescope. Atmospheric parameters and metallicity were derived from the measured equivalent widths of several iron lines using the spectral code moog and Kurucz model atmospheres. We obtained the abundances of O, Al, Ca, Mg, Si, Ti, Ni, Cr, Sc, Y, Zr, La, Ce and Nd by measuring the equivalent widths of the absorption lines of these elements. A mean metallicity of [Fe/H] = 0.05 ± 0.13 relative to the Sun was determined from the data of the red-giant members. This result is in good agreement with the Galactic-disk radial distribution of iron traced by open clusters. We did not find any intrinsic star-to-star scatter in the [element/Fe] ratios for the stars in this cluster. We compare our results with investigations of other open clusters. An age of 8.2 Gyr is derived from isochrone fits.

scholarly journals Detailed chemical composition of the open cluster IC 4651: The iron peak, $\mathsf{\alpha}$ elements, and Li

2004 ◽  
Vol 424 (3) ◽  
pp. 951-963 ◽  
Author(s):  
L. Pasquini ◽  
S. Randich ◽  
M. Zoccali ◽  
V. Hill ◽  
C. Charbonnel ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Open Cluster ◽  
Detailed Chemical

Chemical Composition of a Young Star HD 377

2012 ◽  
Vol 21 (4) ◽  
Author(s):  
Tõnu Kipper
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Main Sequence ◽  
Young Star ◽  
Main Sequence Star ◽  
High Resolution Spectrum ◽  
Atmospheric Parameters

AbstractA high resolution spectrum of a pre-main sequence star HD 377 is analyzed. The atmospheric parameters are found to be: T

scholarly journals Chemical composition of A and F dwarfs members of the Hyades open cluster

2010 ◽  
Vol 523 ◽  
pp. A71 ◽  
Author(s):  
M. Gebran ◽  
M. Vick ◽  
R. Monier ◽  
L. Fossati
Keyword(s):  
Chemical Composition ◽  
Open Cluster

scholarly journals Vilnius Photometry in the Southern Hemisphere

1993 ◽  
Vol 136 ◽  
pp. 51-58 ◽  
Author(s):  
R.J. Dodd ◽  
M.C. Forbes ◽  
D.J. Sullivan
Keyword(s):  
Southern Hemisphere ◽  
Open Cluster ◽  
Photometric System ◽  
Paper Briefly ◽  
Stellar Objects ◽  
Suitable Standard

AbstractThe seven intermediate passband filters of the Vilnius photometric system enable a more comprehensive and discriminating classification of stellar objects than is possible in broadband systems. To date, a lack of suitable standard stars has inhibited its use in the Southern Hemisphere. We have an established programme for extending the network of northern Vilnius standards into the southern skies. This paper briefly summarizes the characteristics of the Vilnius system, provides a synopsis of the data obtained on over 200 standard stars so far and presents preliminary CM and CC diagrams for the open cluster Omicron Velorum (IC2391).

scholarly journals An investigation of the double-mode Cepheid TU Cassiopeiae - I. Atmospheric parameters and chemical composition

1993 ◽  
Vol 265 (2) ◽  
pp. 257-260 ◽  
Author(s):  
S. M. Andrievsky ◽  
V. V. Kovtjukh ◽  
E. N. Makarenko ◽  
I. A. Usenko
Keyword(s):  
Chemical Composition ◽  
Atmospheric Parameters

scholarly journals Heavy metal enrichment in the intermediate He-sdOB pulsator Feige 46

2019 ◽  
Vol 629 ◽  
pp. A148 ◽  
Author(s):  
M. Latour ◽  
M. Dorsch ◽  
U. Heber
Keyword(s):  
Heavy Metal ◽  
Chemical Composition ◽  
Optical Spectrum ◽  
Atmospheric Parameters ◽  
Metal Enrichment ◽  
Uv Spectrum ◽  
Abundance Pattern ◽  
Upper Limits ◽  
Kinematic Properties ◽  
Heavy Metal Enrichment

The intermediate He-enriched hot subdwarf star Feige 46 was recently reported as the second member of the V366 Aqr (or He-sdOBV) pulsating class. Feige 46 is very similar to the prototype of the class, LS IV − 14°116, not only in terms of pulsational properties, but also in terms of atmospheric parameters and kinematic properties. LS IV − 14°116 is additionally characterized by a very peculiar chemical composition, with extreme overabundances of the trans-iron elements Ge, Sr, Y, and Zr. We investigate the possibility that the similarity between the two pulsators extends to their chemical composition. We retrieved archived optical and UV spectroscopic observations of Feige 46 and performed an abundance analysis using model atmospheres and synthetic spectra computed with TLUSTY and SYNSPEC. In total, we derived abundances for 16 elements and provide upper limits for four additional elements. Using absorption lines in the optical spectrum of the star we measure an enrichment of more than 10 000× solar for yttrium and zirconium. The UV spectrum revealed that strontium is equally enriched. Our results confirm that Feige 46 is not only a member of the now growing group of heavy metal subdwarfs, but also has an abundance pattern that is remarkably similar to that of LS IV − 14°116.

scholarly journals 14. White Dwarf Atmospheres

1971 ◽  
Vol 42 ◽  
pp. 81-96 ◽  
Author(s):  
V. Weidemann
Keyword(s):  
Chemical Composition ◽  
Observational Data ◽  
Effective Temperature ◽  
White Dwarf ◽  
General Information ◽  
Stellar Atmospheres ◽  
Surface Gravity ◽  
Atmospheric Parameters

We first consider the general information scheme for the interpretation of observational data (Figure 1). From the relations plotted it is evident that (in going from left to right) this scheme can only be solved if distances are known and if we are able to determine the atmospheric parameters: effective temperature, Teff, surface gravity, g, and chemical composition from observations of colors and spectra – which is the genuine task of the theory of stellar atmospheres.

scholarly journals The chemical composition of the oldest nearby open cluster Ruprecht 147

2018 ◽  
Vol 619 ◽  
pp. A176 ◽  
Author(s):  
Angela Bragaglia ◽  
Xiaoting Fu ◽  
Alessio Mucciarelli ◽  
Gloria Andreuzzi ◽  
Paolo Donati
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Motion Parallax ◽  
Open Cluster ◽  
Red Giants ◽  
Evolutionary Models ◽  
Chemical Abundance ◽  
Cluster Distance ◽  
Very High ◽  
Detailed Chemical

Context. Ruprecht 147 (NGC 6774) is the closest old open cluster, with a distance of less than 300 pc and an age of about 2.5 Gyr. It is therefore well suited for testing stellar evolution models and for obtaining precise and detailed chemical abundance information. Aims. We combined photometric and astrometric information coming from literature and the Gaia mission with very high-resolution optical spectra of stars in different evolutionary stages to derive the cluster distance, age, and detailed chemical composition. Methods. We obtained spectra of six red giants using HARPS-N at the Telescopio Nazionale Galileo (TNG). We also used European Southern Observatory (ESO) archive spectra of 22 main sequence (MS) stars, observed with HARPS at the 3.6 m telescope. The very high resolution (115 000) and the large wavelength coverage (about 380–680 nm) of the twin instruments permitted us to derive atmospheric parameters, metallicity, and detailed chemical abundances of 23 species from all nucleosynthetic channels. We employed both equivalent widths and spectrum synthesis. We also re-derived the cluster distance and age using Gaia parallaxes, proper motions, and photometry in conjunction with the PARSEC stellar evolutionary models. Results. We fully analysed those stars with radial velocity and proper motion/parallax in agreement with the cluster mean values. We also discarded one binary not previously recognised, and six stars near the MS turn-off because of their high rotation velocity. Our final sample consists of 21 stars (six giants and 15 MS stars). We measured metallicity (the cluster average [Fe/H] is +0.08, rms = 0.07) and abundances of light, α, Fe-peak, and neutron-capture elements. The Li abundance follows the expectations, showing a tight relation between temperature and abundance on the MS, at variance with M 67, and we did not detect any Li-rich giant. Conclusions. We confirm that Rup 147 is the oldest nearby open cluster. This makes it very valuable to test detailed features of stellar evolutionary models.

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