NOAO >   Observing Info >   Approved Programs >   2010B-0225

Small NOAO Logo

Proposal Information for 2010B-0225


PI: Andrea Kunder, Cerro Tololo Inter-American Observatory, akunder@ctio.noao.edu
Address: Casilla 603, La Serena, Chile

CoI: Roberto De Propris, Cerro Tololo Inter-American Observatory
CoI: Alistair Walker, Cerro Tololo Inter-American Observatory

Title: The Oosterhoff period shift effect in NGC1851 and NGC2808: nature or nurture ?

Abstract: We propose to measure the metallicities and period-amplitude relations of RR Lyrae with Oosterhoff I and II properties in NGC 1851 and NGC 2808. The former cluster shows a split on the subgiant branch which is likely to be due to an age difference of ~ 1 Gyr, while the latter is known to host Helium enhanced stars. Since both clusters have similar metal abundance ([Fe/H] ~ -1.2) this allows us to separate the role of age and He abundance in the origin of the Oosterhoff dichotomy.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2010B-0225

noaoprop-help@noao.edu

Small NOAO Logo