[Graduados] 24/11 -13h - Seminario FCAG: Hunting for the first stars in the Universe with S-PLUS - Dr. Felipe de Almeida Fernandes (IAG, Universidad de Sao Paulo, Brasil)

[Secretaría de Ciencia y Técnica]

A toda la comunidad,

les informamos que el próximo viernes 24 de noviembre a las 13h, en el 
Salón Meridiano, se brindará la siguiente charla en el marco de los 
Seminarios de la FCAG:*Hunting for the first stars in the Universe with 
S-PLUS*.**La misma estará a cargo del Dr. Felipe de Almeida Fernandes 
(IAG, Universidad de Sao Paulo, Brasil), profesor invitado del Grupo 
ALAS. A continuación les dejamos el resumen y los datos de conexión para 
aquellos que no puedan acercarse al Salón Meridiano.*
*

*Resumen: *Metal-poor stars are key to our understanding of the early 
stages of chemical evolution in the Universe. New multifilter surveys, 
such as the Southern Photometric Local Universe Survey (S-PLUS), are 
greatly advancing our ability to select low-metallicity stars in our 
Galaxy. In a series of papers, we have selected and analyzed a sample of 
522 metal-poor candidates in S-PLUS. Follow-up observations in Blanco 
and Gemini South telescopes, using the COSMOS and GMOS spectrographs, 
confirmed that 92% of the selected stars have [Fe/H] < -1, while 83% 
have [Fe/H] < -2, and 15% [Fe/H] < -3. Our sample also includes two 
stars with spectroscopic metallicity below -4. Based on this sample, we 
proposed further selection criteria by combining S-PLUS and Gaia DR3 
data and showed that we were able to improve the purity of the 
selection, achieving fractions of 99.5% and 91% for [Fe/H] ≤ -1 and 
[Fe/H] ≤ -2, respectively. We also performed high-resolution 
spectroscopic follow-ups for two peculiar stars in the sample: i) SPLUS 
J2104−0049 was observed in the Magellan-Clay telescope and found to be 
the ultra metal-poor star ([Fe/H] < -4) with the lowest ever detected 
carbon abundance (at the time of our publication). ii) More recently, 
SPLUS J1424-2542 was observed during the system verification of the 
GHOST instrument, installed at the Gemini South telescope. Our 
preliminary results reveal that this star is not only a metal-poor star 
with low carbon abundance, but is also enriched in r-process elements.

**

***Datos de conexión:* **

** ** **
**
Unirse a la reunión zoom: https://us02web.zoom.us/j/89642687970
ID de reunión: 896 4268 7970
Código de acceso: 526656

*A fin de reducir el uso de residuos plásticos, les solicitamos que se 
acerquen con sus propias tazas para el café.*
Aunque este seminario será en formato híbrido, esperamos contar con su 
presencia.

Saludos,

Secyt-FCAG

-- 
Secretaría de Ciencia y Técnica
Facultad de Ciencias Astronómicas y Geofísicas
Horario de atención: lunes a viernes de 8hs a 15hs
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