SIMBAD references

2019MNRAS.488..482P - Mon. Not. R. Astron. Soc., 488, 482-494 (2019/September-1)

The s-process enriched star HD 55496: origin from a globular cluster or from the tidal disruption of a dwarf galaxy?


Abstract (from CDS):

We present a new abundance analysis of HD 55496, previously known as a metal-poor barium star. We found that HD 55496 has a metallicity [Fe/H] = -1.55 and is s-process enriched. We find that HD 55496 presents four chemical peculiarities: (i) a Na-O abundance anticorrelation; (ii) it is aluminium rich; (iii) it is carbon poor for an s-process enriched star, and (iv) the heavy second s-process peak elements, such as Ba, La, Ce, and Nd, present smaller abundances than the light s-process elements, such as Sr, Y, and Zr, which is not usually observed among the chemically peculiar binary stars at this metallicity. The heavy-element abundance pattern suggests that the main source of the neutrons is the 22Ne(α,n)25Mg reaction. Taking all these abundance evidences together into consideration strongly suggests that HD 55496 is a 'second-generation of globular cluster stars' formed from gas already strongly enriched in s-process elements and now is a field halo object. Our dynamical analysis, however, indicates that the past encounter probabilities with the known globular clusters are very low (≤6 per cent). This evidence, together with the retrograde motion, points to a halo intruder possibly originated from the tidal disruption of a dwarf galaxy.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): nuclear reactions, nucleosynthesis, abundances - stars: abundances - stars: chemically peculiar - stars: evolution - stars: fundamental parameters - stars: individual: HD 55496

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR.

Simbad objects: 11

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