Mining S-PLUS for Metal-Poor Stars in the Milky Way

Abstract

This work presents the medium-resolution ($R\sim 1,500$) spectroscopic follow-up of 522 low-metallicity star candidates from the Southern Photometric Local Universe Survey (S-PLUS). The objects were selected from narrow-band photometry, taking advantage of the metallicity-sensitive S-PLUS colors. The follow-up observations were conducted with the Blanco and Gemini South telescopes, using the COSMOS and GMOS spectrographs, respectively. The stellar atmospheric parameters (T${}_{\mathrm{eff}}$, log$g$, and [Fe/H]), as well as carbon and $\alpha$-element abundances, were calculated for the program stars in order to assess the efficacy of the color selection. Results show that $92_{-3}^{+2}\%$ of the observed stars have [Fe/H]$\le -1.0$, $83_{-3}^{+3}\%$ have [Fe/H]$\le -2.0$, and $15_{-3}^{+3}\%$ have [Fe/H]$\le -3.0$, including two ultra metal-poor stars ([Fe/H]$\le -4.0$). The 80th percentile for the metallicity cumulative distribution function of the observed sample is [Fe/H]$=-2.04$. The sample also includes 68 Carbon-Enhanced Metal-Poor (CEMP) stars. Based on the calculated metallicities, further S-PLUS, color cuts are proposed, which can increase the fractions of stars with [Fe/H]$\le -1.0$ and $\le -2.0$ to $98\%$ and $88\%$, respectively. Such high success rates enable targeted high-resolution spectroscopic follow-up efforts, as well as provide selection criteria for fiber-fed multiplex spectroscopic surveys.

21 pages, 10 figures, accepted for publication on ApJS

References in corpus (24)

• Array Programming with NumPy
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Dartmouth Stellar Evolution Database
• Galactic chemical evolution: Carbon through Zinc
• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• The SEGUE Stellar Parameter Pipeline. I. Description and Initial Validation Tests
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• Carbon-Enhanced Metal-Poor Star Frequencies in the Galaxy: Corrections for the Effect of Evolutionary Status on Carbon Abundances
• The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters
• CH in stellar atmospheres: an extensive linelist
• The Frequency of Carbon-Enhanced Metal-Poor Stars in the Galaxy from the HERES sample
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• TOPoS: II. On the bimodality of carbon abundance in CEMP stars. Implications on the early chemical evolution of galaxies
• An Elemental Assay of Very, Extremely, and Ultra Metal-Poor Stars
• Population Studies. XIII. A New Analysis of the Bidelman-MacConnell "Weak-Metal" Stars - Confirmation of Metal-Poor Stars in the Thick Disk of the Galaxy
• Bright Metal-Poor Stars from the Hamburg/ESO Survey. II. A Chemodynamical Analysis
• Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys
• The Pristine survey III: Spectroscopic confirmation of an efficient search for extremely metal-poor stars
• Exploring the Galaxy's halo and very metal-weak thick disk with SkyMapper and Gaia DR2
• On the inconsistency of [C/Fe] abundances and the fractions of carbon-enhanced metal-poor stars among various stellar surveys
• Dynamically Tagged Groups of Metal-Poor Stars from the Best \& Brightest Survey
• Milky Way tomography with the SkyMapper Southern Survey: I: Atmospheric parameters and distances of one million red giants
• KOSMOS and COSMOS: New facility instruments for the NOAO 4-meter telescopes
• Learning about stars from their colors

Cited by in corpus (1)

• The Pristine survey -- XX: GTC follow-up observations of extremely metal-poor stars identified from Pristine and LAMOST