HE0107-5240. Credit: NASA.
HE0107-5240 is the second most metal-poor star known. It has a metallicity of less than -5.0 and a corresponding iron content that is some 200,000 times less than that of the Sun. On this basis, it is the second oldest known star in the Milky Way Galaxy with an estimated age of about 12 billion yr. HE1327-2326 lies in the constellation Phoenix (RA 01h 09m 29.1s, Dec -52° 24' 20") at a distance of 36,000 light-years. It has about four-fifths the mass of the Sun and a visual magnitude of 15.9.
1. Christlieb, N., Bessell, M. S., Gustafsson, B., Korn, A., Barklem, P. S., Karisson T., Mizuno-Wiedner M., and Rossi, S. "A stellar relic from the early Milky Way," Nature, 419, 904-906 (2002).