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Projeto Observacional para 2016A - SO2016A-014

Autor: Alan Alves Brito
Instituição: UFRGS
e-mail: alan.brito@ufrgs.br

Basílio X. Santiago
Ana Chies-Santos
Dinalva Aires de Sales
Eduardo Bica
Gabriel Aguiar
Juliana Crestani
Rafael Dias
Adriano Pires
Pedro Henrique Macedo
Alejandra Romero
Daniela Borges Pavani
Emilio Zanatta
Arthur Alencastro PULS
Anna Barbara Queiroz

Título: The UFRGS Open Cluster Survey (UOCS): searching for chemical anomalies in Galactic open clusters through CN and CH molecular band strengths

Resumo: Galactic Open Clusters (GOCs) are perhaps the only entities we can still call simple stellar populations. While multiple stellar populations (MPs) have been found in most globular clusters (GCs), the extent of MPs in GOCs is still widely discussed in the literature. Is the total mass of a star cluster the main parameter to determine the MP phenomenon? Are there star-to-star variations of CN and CH bands in GOCs, as it has widely been detected in GCs? This Large Term Programme will address the questions outlined above with low-resolution GOODMAN spectra on SOAR. We will characterise a statistically significant number of giant stars (or candidates) in a selected sample of GOCs. We will therefore (i) increase the number of GOCs that have been spectroscopically surveyed to date; (ii) calculate radial velocities, hence membership, for many stars; (iii) understand their chemical distribution (from CN-CH bands) of giant stars, and (iv) impose important observational constraints on the lower mass (if any) necessary to start contributing for the formation of MPs in clusters.