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B. P. L. Ferreira

Publications and source records attributed to B. P. L. Ferreira.

2 recordsLinked to original sources

Astrometric and Spectroscopic Analysis of IC 2714: An Open Cluster Hosting a Lithium-Rich Giant

Open clusters serve as laboratories to study and evaluate stellar evolution and Galactic chemical evolution models. Chemical peculiarities, such as lithium-rich giants, are rarely observed in these stellar systems. This work focuses on eight red giants (#005, #028, #034, #053, #087, #121, #126, and #190) previously reported as members of the Galactic cluster IC 2714. We conducted a detailed investigation using high-resolution spectroscopy, supplemented with data from the Gaia DR3 catalog. Besides deriving the cluster's fundamental parameters, we provide the most thorough chemical characterization of IC 2714 to date, reporting the abundance of 23 species, including light elements (Li, C, N, O), odd-Z elements (Na, Al), $α$-elements (Si, Ca, Ti, Mg), iron-peak elements (Sc, Cr, Ni), $\textit{s}$-process-dominated elements (Y, Zr, Ba, La, Ce, Nd) and $\textit{r}$-process elements (Sm, Eu). We also present the carbon isotopic ratios $^{12}$C/$^{13}$C for the first time for seven stars. One particular star (#087) exhibits a high lithium abundance ($\log \varepsilon$(Li)$_{\rm NLTE}$ = $+$1.54 dex) and a slightly higher projected rotational velocity ($v \sin i$ = 6.7 km s$^{-1}$). Our results suggest that the analyzed stars are in the core-helium-burning phase of evolution, where the most lithium-rich giants are found. Combining astrometric probabilities and chemical abundances, we conclude that two giants (#028 and #034) might not be cluster members.

astro-ph.GA↗

The VISCACHA survey XIV. Chemical evolution history of the SMC: The Southern Bridge Clusters

The chemical evolution history of the Small Magellanic Cloud (SMC) is complex and is best understood through a comprehensive analysis of star clusters across its various regions. The VISCACHA survey aims to fully explain the chemical evolution of SMC star clusters by analyzing different sub-regions adopted from an existing framework. The west halo (WH) region, which contains the oldest and most metal-poor stellar populations, exhibits a clear age-metallicity relation (AMR) with minimal dispersion. This region shows a significant dip of ~0.5 dex in metallicity approximately 6 Gyr ago. This was likely caused by a major merger event that subsequently accelerated the star formation rate. Clusters in the Southern Bridge (SB) and Northern Bridge regions of the SMC may have experienced distinct chemical enrichment histories, as suggested by our previous works but with limited data coverage. Furthermore, the AMR of wing/bridge (W/B) shows no sign of enrichment caused by the aforementioned merger event, but exhibits signatures of the recent collisions between the clouds contemporaneous with the epochs of the Magellanic Stream and Bridge formations. In this study, we present an updated AMR for the SB region based on a sample that includes approximately 67% of its known clusters. Contrary to the expectation of a very unique chemical evolution history, these SB clusters show a trend similar to the one of the WH clusters. The chemical evolution models that best fit the AMR trend of the SB clusters show excellent agreement with the major merger model proposed for the WH clusters. Building on this, we suggest a new unified chemical evolution model for both the WH and SB clusters, which can be explained by a major merger at ~6 Gyr followed by episodic chemical enrichment over time.

astro-ph.GA↗