SPLUS J210428.01?004934.2: An Ultra Metal-poor Star Identified from Narrowband Photometry*

We report on the discovery of SPLUS J210428.01-004934.2, an ultra metal-poor (UMP) star first identified from narrow-band photometry Southern Photometric Local Universe Survey (S-PLUS) Data Release 1, in SDSS Stripe 82 region. Follow-up medium- and high-resolution spectroscopy (with Gemini South Magellan-Clay, respectively) confirmed effectiveness search for low-metallicity stars using S-PLUS photometry. At [Fe/H]=-4.03, J2104-0049 has lowest detected carbon abundance, A(C)=+4.34, when compared to 34 previously known UMP literature, which is important constraint its stellar progenitor also evolution models at metallicities. Based chemical abundance pattern, we speculate that could be a bonafide second-generation star, formed gas cloud polluted by single metal-free ~30Mo star. This opens possibility finding additional directly photometric surveys, potentially powerful method help complete inventory such peculiar objects our Galaxy.