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SkyMapper Protected Science Project

The SkyMapper Survey Search for Extremely Metal-Poor Stars

Gary Da Costa (RSAA), Martin Asplund (RSAA), Michael Bessell (RSAA), Andy Casey (Cambridge), Anna Frebel (MIT), Alex Heger (Monash), Heather Jacobson (MIT), Stefan Keller (RSAA), Karin Lind (Uppsala), Fabiola Marino (RSAA), John Norris (RSAA), Brian Schmidt (RSAA), David Yong (RSAA)

SkyMapper uvgi photometry is used to select candidate Extremely Metal-Poor (EMP) stars using the metallicity sensitivity provided by the SkyMapper v filter. Candidates brighter than g ~ 15.5 are followed-up spectroscopically at the 2.3m with the resulting high probability candidates then observed at high dispersion using facilities at Magellan and Keck. The program has already resulted in the discovery of the most iron-poor star known (Keller et al., 2014, Nature, 506, 463). The ultimate aims of the program are a much improved characterisation of the Metallicity Distribution Function at the lowest metallicities, a more complete understanding of the role of carbon enhancement in the formation of the most metal-poor stars, and improved constraints on the mass function of the first generation of metal-free stars. The program will also provide much new information on the formation of the chemical elements. The survey will use both Short Survey and Main Survey data.