Cayrel's Star

Starbox begin
name=BPS CS31082-0001 Starbox observe
epoch=J2000
constell=Cetus
ra=01h 29m 30.31s
dec=-16° 08' 5.51"
appmag_v=11.7 Starbox catalog
names=BD -16°251, CS31082-001

BPS CS31082-0001, named Cayrel's Star, is an old Population II star located in a distance of 4 kpc in the Galactic Halo. It belongs to the class of ultra-metal-poor stars (Metallicity [Fe/H] =-2.9), especially the very rare subclass of neutron-capture enhanced stars. It was discovered by Tim C. Beers and collaborators with the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory in Chile and analyzed by Roger Cayrel and collaborators. They used the Very Large Telescope (VLT) at the European Southern Observatory in Paranal, Chile for high-resolution optical spectroscopy to determine elemental abundances. The Thorium-232 to Uranium-238 ratio was used to determine the age. It is estimated to be about 12.5 billion years old, making it one of the oldest known.

Compared to other ultra-metal-poor, r-process enriched stars (as CS22892-052, BD+17°3248) CS31082-001 has higher abundances of the actinides (Th, U), but a surprisingly low Pb abundance.

References

* BEERS T.C., PRESTON G.W., SHECTMAN S.A., "A search for stars of very low metal abundance. I.", Astron. J., 90, 2089-2102 (1985)
* BEERS T.C., PRESTON G.W., SHECTMAN S.A., "A search for stars of very low metal abundance. II.", Astron. J., 103, 1987-2034 (1992)
* Cayrel, R.; Hill, V.; Beers, T. C.; Barbuy, B.; Spite, M.; Spite, F.; Plez, B.; Andersen, J.; Bonifacio, P.; François, P.; Molaro, P.; Nordström, B.; Primas, F., "Measurement of stellar age from uranium decay", Nature, Volume 409, Issue 6821, pp. 691-692 (2001)
* H. Schatz, R. Toenjes, B. Pfeiffer, T.C. Beers, J.J. Cowan, V. Hill, K.-L. Kratz, "Thorium and Uranium Chronometres applied to CS 31082-001", Ap. J.579 (2002) 628 - 638

External links

* [http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=bps+cs31082-0001 SIMBAD-Entry] (SIMBAD)
* [http://dkcmzc.chemie.uni-mainz.de/~pfeiffer/ages.html R-Process Cosmo-Chronometers]