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J/A+A/606/A112      Abundance analysis of ALW Carina 8         (Susmitha+, 2017)

Abundance analysis of a CEMP-no star in the Carina dwarf spheroidal galaxy. Susmitha A., Koch A., Sivarani T. <Astron. Astrophys. 606, A112 (2017)> =2017A&A...606A.112S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Stars, carbon ; Abundances Keywords: stars: abundances - binaries: spectroscopic - stars: carbon - Galaxy: abundances - galaxies: dwarf Abstract: Carbon-enhanced metal-poor (CEMP) stars bear important imprints of the early chemical enrichment of any stellar system. While these stars are known to exist in copious amounts in the Milky Way halo, detailed chemical abundance data from the faint dwarf spheroidal (dSph) satellites are still sparse, although the relative fraction of these stars increases with decreasing metallicity. Here, we report the abundance analysis of a metal-poor ([Fe/H]=-2.5dex), carbon-rich ([C/Fe]=1.4dex) star, ALW-8, in the Carina dSph using high-resolution spectroscopy obtained with the ESO/UVES instrument. Its spectrum does not indicate any over-enhancements of neutron capture elements. Thus classified as a CEMP-no star, this is the first detection of this kind of star in Carina. Another of our sample stars, ALW-1, is shown to be a CEMP-s star, but its immediate binarity prompted us to discard it from a detailed analysis. The majority of the 18 chemical elements we measured are typical of Carina's field star population and also agree with CEMP stars in other dSph galaxies. Similar to the only known CEMP-no star in the Sculptor dSph and the weak-r-process star HD 122563, the lack of any strong barium-enhancement is accompanied by a moderate overabundance in yttrium, indicating a weak r-process activity. The overall abundance pattern confirms that, also in Carina, the formation site for CEMP-no stars has been affected by both faint supernovae and by standard core collapse supernovae. Whichever process was responsible for the heavy element production in ALW-8 must be a ubiquitous source to pollute the CEMP-no stars, acting independently of the environment such as in the Galactic halo or in dSphs. Description: File tableA1.dat contains the linelist for the EW analysis,abundance and abundance uncertainties to 1 sigma scatter in the stellar parameters for ALW-8. Objects: -------------------------------------------------- RA (2000) DE Designation(s) -------------------------------------------------- 06 41 46.27 -50 58 55.9 ALW-8 = ALW Carina 8 -------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 54 58 Linelist for the EW analysis, abundance and abundance uncertainties to 1 sigma scatter in the stellar parameters for ALW-8
Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 5 A5 --- Element Element name and ionisation 9- 15 F7.2 0.1nm lambda Line wavelength 17- 20 F4.2 eV Chi Exitation potential 22- 27 F6.2 --- loggf Oscillator strength 29- 31 I3 0.1nm EW ? Equivalent width 32 A1 --- n_EW [s] s for syn 34 A1 --- l_A(x) Limit flag on A(x) 35- 39 F5.2 [-] A(x) Abundance 41- 44 F4.2 100K dT Abundance uncertainty to 1 sigma scatter in the temperature, δT 46- 49 F4.2 [0.25cm/s2] dlogg Abundance uncertainty to 1 sigma scatter in the gravity, δlogg 51- 54 F4.2 0.2km/s dxi Abundance uncertainty to 1 sigma scatter in the microturbulent velocity, δxi
Acknowledgements: Antony Susmitha, susmitharaniantony(at)gmail.com
(End) Patricia Vannier [CDS] 19-Jun-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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