NOAO >   Observing Info >   Approved Programs >   2003B-0248

Small NOAO Logo

Proposal Information for 2003B-0248


PI: Olivier Schnurr, Universite de Montreal, schnurr@astro.umontreal.ca
Address: Departement de Physique, CP 6128 succ. centre-ville, Montreal, QC H1Y 3C2, Canada

CoI: Anthony F.J. Moffat, Universite de Montreal
CoI: Nicole St-Louis, Universite de Montreal

Title: WNLh Stars - the Most Massive Stars in the Universe?

Abstract: We propose to conclude our intensive and complete time-dependent spectroscopic study of all 47 known WNL stars in the LMC, an ideal laboratory to study the effect of lower ambient metallicity, Z, on stellar evolution. WNL stars are luminous, cooler WR stars of the nitrogen sequence. This will allow us to: 1) determine the binary frequency. The Roche-lobe overflow (RLOF) mechanism in close binaries is predicted to be responsible for the formation of a significant fraction of WR stars in low Z environments such as the LMC. 2) determine the masses. Since some of these stars (denoted WNL(h) or WNLh) are supposed to be hydrogen-burning and thus main-sequence stellar objects of the highest luminosity, they may be the most massive stars known. 3) study wind-wind collision (WWC) effects in WR+O binaries involving very luminous WNL stars with strong winds. Interesting in itself as a high-energy phenomenon, WWC is in competition with conservative RLOF (i.e. mass transfer to the secondary star), and therefore has to be taken into account in this context.


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 >   2003B-0248

noaoprop-help@noao.edu

Small NOAO Logo