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Enrichment of the Galactic disc with neutron-capture elements: Mo and Ru

Mishenina, T; Pignatari, M; Gorbaneva, T; Travaglio, C; Côté, B; Thielemann, F.-K; Soubiran, C


T Mishenina

T Gorbaneva

C Travaglio

B Côté

F.-K Thielemann

C Soubiran


We present new observational data for the heavy elements molybdenum (Mo, Z = 42) and ruthenium (Ru, Z = 44) in F-, G-, and K-stars belonging to different substructures of the Milky Way. The range of metallicity covered is-1.0 < [Fe/H] < +0.3. The spectra of Galactic disc stars have a high resolution of 42,000 and 75,000 and signal-to-noise ratio better than 100. Mo and Ru abundances were derived by comparing the observed and synthetic spectra in the region of Mo I lines at 5506, 5533Å5533Å for 209 stars and Ru I lines at 4080, 4584, 4757Å4757Å for 162 stars using the LTE approach. For all the stars, the Mo and Ru abundance determinations are obtained for the first time with an average error of 0.14 dex. This is the first extended sample of stellar observations for Mo and Ru in the Milky Way disc, and together with earlier observations in halo stars it is pivotal in providing a complete picture of the evolution of Mo and Ru across cosmic timescales. The Mo and Ru abundances were compared with those of the neutron-capture elements (Sr, Y, Zr, Ba, Sm, Eu). The complex nucleosynthesis history of Mo and Ru is compared with different Galactic Chemical Evolution (GCE) simulations. In general, present theoretical GCE simulations show underproduction of Mo and Ru at all metallicities compared to observations. This highlights a significant contribution of nucleosynthesis processes not yet considered in our simulations. A number of possible scenarios are discussed.

Journal Article Type Article
Publication Date 2019
Journal Mon. Not. R. Astron. Soc
Print ISSN 0035-8711
Publisher Oxford University Press (OUP)
Peer Reviewed Peer Reviewed
Volume 000
Pages 1-20
Institution Citation Mishenina, T., Pignatari, M., Gorbaneva, T., Travaglio, C., Côté, B., Thielemann, F., & Soubiran, C. (2019). Enrichment of the Galactic disc with neutron-capture elements: Mo and Ru. Monthly notices of the Royal Astronomical Society, 000, 1-20.
Keywords Stars: abundances; Stars: late-type; Galaxy: disc; Galaxy: evolution
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© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

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