(Re)Discovery and analysis of metal-poor stars in the Milky Way

• Grant number: 12/13722-1
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: February 01, 2013
• End date: January 31, 2014
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Silvia Cristina Fernandes Rossi
• Grantee: Vinicius Moris Placco
• Supervisor: Timothy C. Beers
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Kitt Peak National Observatory (KPNO), United States
• Associated to the scholarship: 10/08996-0 - The Milky Way Halo Revisited, BP.PD

Abstract

This proposal seeks to discover (and re-discover) metal-poor stars in the Galaxy, by means of spectroscopic analysis, ranging from low- to high-resolution observations. These discoveries will be made by continuing the efforts started in 2007, which selected a sample of thousands of carbon-enhanced metal-poor star candidates, based on their low-resolution spectra from objective-prism plates. The first estimate of the stellar parameters for these stars are possible via medium-resolution follow-up spectroscopy, and data collected over the last four years is being analyzed. Some of the most interesting candidates have already been the subject of high-resolution studies, with the goal of unveiling their complete chemical abundance patterns. Besides that, the tools used to process the aforementioned data will also be used in the analysis of a recent survey dedicated to the evolution of Galactic structures. The re-discoveries will take place by processing medium-resolution spectra of metal-poor stars gathered over the last 25 years by a number of telescopes, using tools specially adapted for this purpose. Since these data were carefully selected among metal-poor star candidates, it is expected that the outcome of this analysis will yield additional targets for high-resolution follow-up spectroscopy. Detailed analysis of such peculiar objects can help shed light on fundamental questions regarding both Milky Way structure and chemical evolution. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PLACCO, VINICIUS M.; FREBEL, ANNA; BEERS, TIMOTHY C.; KARAKAS, AMANDA I.; KENNEDY, CATHERINE R.; ROSSI, SILVIA; CHRISTLIEB, NORBERT; STANCLIFFE, RICHARD J.. METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. I. CONSTRAINTS ON PROGENITOR MASS AND METALLICITY OF AGB STARS UNDERGOING s-PROCESS NUCLEOSYNTHESIS. ASTROPHYSICAL JOURNAL, v. 770, n. 2, JUN 20 2013. (12/13722-1, 10/08996-0)

LEE, YOUNG SUN; BEERS, TIMOTHY C.; MASSERON, THOMAS; PLEZ, BERTRAND; ROCKOSI, CONSTANCE M.; SOBECK, JENNIFER; YANNY, BRIAN; LUCATELLO, SARA; SIVARANI, THIRUPATHI; PLACCO, VINICIUS M.; et al. CARBON-ENHANCED METAL-POOR STARS IN SDSS/SEGUE. I. CARBON ABUNDANCE ESTIMATION AND FREQUENCY OF CEMP STARS. ASTRONOMICAL JOURNAL, v. 146, n. 5, NOV 2013. (12/13722-1)

PLACCO, VINICIUS M.; FREBEL, ANNA; BEERS, TIMOTHY C.; CHRISTLIEB, NORBERT; LEE, YOUNG SUN; KENNEDY, CATHERINE R.; ROSSI, SILVIA; SANTUCCI, RAFAEL M.. METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. II. DISCOVERY OF FOUR STARS WITH [Fe/H] <=-3.5. ASTROPHYSICAL JOURNAL, v. 781, n. 1, JAN 20 2014. (12/13722-1)