Stellar parameters to S-PLUS stars through SED fitting

• Grant number: 21/09528-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2021
• End date: May 31, 2022
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Felipe de Almeida Fernandes
• Grantee: Guilherme Fabricio Bolutavicius
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 19/26492-3 - Science with the Brazilian robotic telescope, AP.ESP

Abstract

It's undeniable that knowing stellar parameters (effective temperature, surface gravity and metallicity) is important for many fields in astronomy. One way to obtain these parameters is through multi-band photometry, like the one provided by the S-PLUS survey. The outstanding characteristic of S-PLUS is the use of 12 filters, including 5 broad-bands and 7 narrow-bands centered in key spectral features sensitive to metallicity (like J0378, around the OII line) and surface gravity (J0515, around the Mgb triplet). Another advantage of S-PLUS is that the pipeline developed for its calibration use a SED fitting technique (synthetic stellar spectra are fitted to the spectral energy distribution estimated using the photometric magnitudes), which means that these parameters are obtained during the calibration process. However, our preliminary analysis show that the current adjusted spectra suffer from the degeneracy problem between effective temperature and extinction, which can result in an incorrect photometric calibration. This project aims to improve the current SED fitting of the calibration pipeline (adopting a Bayesian approach in the fitting and an interpolation of the synthetic models to better cover the parameter space) to obtain more accurate parameters and at the same time improve the photometric calibration of S-PLUS.