Chances for earth-like planets and life around metal-poor stars
arXiv:astro-ph/0301080
Abstract
We discuss the difficulties of forming earth-like planets in metal-poor environments, such as those prevailing in the Galactic halo (Pop II), the Magellanic Clouds, and the early universe. We suggest that, with less heavy elements available, terrestrial planets will be smaller size and lower mass than in our solar system (solar metallicity). Such planets may not be able to sustain life as we know it. Therefore, the chances of very old lifeforms in the universe are slim, and a threshold metallicty (1/2 solar?) may exist for life to originate on large enough earth-like planets.
5 pages, IAU Symp. 213, ed. R. Norris, C. Oliver, F. Stootman, in press