On the neutron-capture elements across the Galactic thin disk using Cepheids

Abstract

We present new accurate abundances for five neutron-capture (Y, La, Ce, Nd, Eu) elements in 73 classical Cepheids located across the Galactic thin disk. Individual abundances are based on high spectral resolution (R ~ 38,000) and high signal-to-noise ratio (S/N ~ 50-300) spectra collected with UVES at ESO VLT for the DIONYSOS project. Taking account for similar Cepheid abundances provided either by our group (111 stars) or available in the literature, we end up with a sample of 435 Cepheids covering a broad range in iron abundances (-1.6 < [Fe/H] < 0.6). We found, using homogeneous individual distances and abundance scales, well defined gradients for the above elements. However, the slope of the light s-process element (Y) is at least a factor of two steeper than the slopes of heavy s- (La, Ce, Nd) and r- (Eu) process elements. The s to r abundance ratio ([La/Eu]) of Cepheids shows a well defined anticorrelation with of both Eu and Fe. On the other hand, Galactic field stars attain an almost constant value and only when they approach solar iron abundance display a mild enhancement in La. The [Y/Eu] ratio shows a mild evidence of a correlation with Eu and, in particular, with iron abundance for field Galactic stars. We also investigated the s-process index - [hs/ls] - and we found a well defined anticorrelation, as expected, between [La/Y] and iron abundance. Moreover, we found a strong correlation between [La/Y] and [La/Fe] and, in particular, a clear separation between Galactic and Sagittarius red giants. Finally, the comparison between predictions for low-mass asymptotic giant branch stars and the observed [La/Y] ratio indicate a very good agreement over the entire metallicity range covered by Cepheids. However, the observed spread, at fixed iron content, is larger than predicted by current models.

30 pages, 12 figures, 7 tables. Accepted for publication in the Astronomy and Astrophysics journal

References in corpus (20)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Evolution, nucleosynthesis and yields of AGB stars at different metallicities (III): intermediate mass models, revised low mass models and the ph-FRUITY interface
• A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)
• The elemental composition of the Sun II. The iron group elements Sc to Ni
• The exotic chemical composition of the Sagittarius dwarf Spheroidal galaxy
• A high resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
• The elemental composition of the Sun III. The heavy elements Cu to Th
• On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk
• Abundance gradients in the Milky Way for alpha elements, Iron peak elements, Barium, Lanthanum and Europium
• The distance to the Galactic Centre based on Population-II Cepheids and RR Lyrae stars
• VLT/FLAMES spectroscopy of red giant branch stars in the Fornax dwarf spheroidal galaxy
• Galactic abundance gradients from Cepheids : On the iron abundance gradient around 10-12 kpc
• On the distance of the Magellanic Clouds using Cepheid NIR and optical-NIR Period Wesenheit Relations
• New insights on Ba over-abundance in open clusters. Evidence for the intermediate neutron-capture process at play?
• Cepheid Variables in the Flared Outer Disk of our Galaxy
• On the need of the Light Elements Primary Process (LEPP)
• Oxygen, α-element and iron abundance distributions in the inner part of the Galactic thin disc
• No evidence for protoplanetary disk destruction by OB stars in the MYStIX sample
• The r-process in Magnetorotational Supernovae
• Discovery of a Pair of Classical Cepheids in an Invisible Cluster Beyond the Galactic Bulge

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