| Full text | |
| Author(s): |
Limberg, Guilherme
[1]
;
Santucci, Rafael M.
[2, 3]
;
Rossi, Silvia
[1]
;
Shank, Derek
[4, 5]
;
Placco, Vinicius M.
[6]
;
Beers, Timothy C.
[4, 5]
;
Schlaufman, Kevin C.
[7]
;
Casey, Andrew R.
[8, 9]
;
Perottoni, Helio D.
[1]
;
Lee, Young Sun
[10]
Total Authors: 10
|
| Affiliation: | [1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Astron, BR-05508090 Sao Paulo, SP - Brazil
[2] Univ Fed Goias, Inst Fis, Campus Samambaia, BR-74001970 Goiania, Go - Brazil
[3] Univ Fed Goias, Inst Estudos Socioambientais Planetario, BR-74055140 Goiania, Go - Brazil
[4] Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 - USA
[5] Univ Notre Dame, JINA Ctr Evolut Elements, Notre Dame, IN 46556 - USA
[6] NSFs NOIRLab, Community Sci & Data Ctr, 950 N Cherry Ave, Tucson, AZ 85719 - USA
[7] Johns Hopkins Univ, Dept Phys & Astron, 3400 North Charles St, Baltimore, MD 21218 - USA
[8] Monash Univ, Sch Phys & Astron, Wellington Rd, Clayton, Vic 3800 - Australia
[9] ARC Ctr Excellence All Sky Astrophys 3 Dimens AST, Canberra, ACT 2611 - Australia
[10] Chungnam Natl Univ, Dept Astron & Space Sci, Daejeon 34134 - South Korea
Total Affiliations: 10
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 913, n. 1 MAY 2021. |
| Web of Science Citations: | 0 |
| Abstract | |
We present the results of spectroscopic follow-up for 1897 low-metallicity star candidates, selected from the Best \& Brightest (B\&B) Survey, carried out with the GMOS-N/S (Gemini North/South telescopes) and Goodman (SOAR Telescope) spectrographs. From these low-resolution (R similar to 2000) spectra, we estimate stellar atmospheric parameters, as well as carbon and magnesium abundance ratios. We confirm that 56% of our program stars are metal-poor ({[}Fe/H] < - 1.0), 30% are very metal-poor (VMP; {[}Fe/H] < - 2.0), and 2% are extremely metal-poor (EMP; {[}Fe/H] < - 3.0). There are 191 carbon-enhanced metal-poor (CEMP) stars, resulting in CEMP fractions of 19% and 43% for the VMP and EMP regimes, respectively. A total of 94 confirmed CEMP stars belong to Group I (A(C) greater than or similar to 7.25) and 97 to Group II (A(C) less than or similar to 7.25) in the Yoon-Beers A(C)-{[}Fe/H] diagram. Moreover, we combine these data with Gaia EDR3 astrometric information to delineate new target-selection criteria, which have been applied to the Goodman/SOAR candidates, to more than double the efficiency for identification of bona fide VMP and EMP stars in comparison to random draws from the B\&B catalog. We demonstrate that this target-selection approach can achieve success rates of 96%, 76%, 28%, and 4% for {[}Fe/H] <= - 1.5, <= - 2.0, <= - 2.5 and <= - 3.0, respectively. Finally, we investigate the presence of dynamically interesting stars in our sample. We find that several VMP/EMP ({[}Fe/H] <= - 2.5) stars can be associated with either the disk system or halo substructures like Gaia-Sausage/Enceladus and Sequoia. (AU) | |
| FAPESP's process: | 14/18100-4 - Stellar populations in the Milky Way: bulge, halo, disk and star forming regions; instrumentation for high resolution spectroscopy |
| Grantee: | Beatriz Leonor Silveira Barbuy |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 15/50374-0 - Mosaic: the multi-object spectrograph for the ESO Extremely Large Telescope |
| Grantee: | Silvia Cristina Fernandes Rossi |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 18/21250-9 - Identification of bright ultra-metal-poor stars from Multi-Band photometry and spectroscopic follow-up |
| Grantee: | Hélio Dotto Perottoni |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |