How young are the low-mass X-ray binaries ? Conclusions from a flux-limited sample.
Abstract
Low-mass X-ray binaries fall into two classes on the basis of their X-ray properties. Using a flux-limited sample from the Ariel V Sky Survey, we show that the class sometimes referred to as the X-ray bursters is associated with the Galactic disk, and probably has an age of only 10 exp 7 to 10 exp 8 yr, much younger than was previously thought. The short lifetime of these 'disk sources' explains why there are so many millisecond pulsars, and how a system such as Her X-1 can have a relatively massive secondary. Conversely, the 'bright blue sources' seem to be associated with a highly flattened, old, metal-rich inner bulge population.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 1993
- DOI:
- 10.1093/mnras/262.4.929
- Bibcode:
- 1993MNRAS.262..929N
- Keywords:
-
- Chronology;
- Galactic Structure;
- Pulsars;
- Stellar Mass;
- X Ray Binaries;
- Galactic Bulge;
- Neutron Stars;
- Astrophysics