The following document lists the file abstract/SUNGER_PSR1259.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
PSR B1259-63 is a unique system, it is the only known radio pulsar orbiting a Be star (Johnston 1992 ApJ 387 L37). The 48ms pulsar has a surface magnetic field strength of 3x10^11G and a characterstic spin down age of 3x10^5yr. The pulsar's companion SS 2883 a 10th mag B2Ve star (approx 10 solar masses and radius approx 6xRsun). The pulsar is in a 3.4yr orbit around its companion with an eccentricty of 0.87, the highest known for all neutron star binaries. Pulsars in traditional high mass X-ray binaries are thought to accrete material from the Be star disk resulting in transient X-ray outbursts pulsed at the neutron star spin period. Observations during the last periastron passage (before ISO was launched) revealed that the X-ray emission was unpulsed. It is thought that the X-rays are produced at the shock front which occurs at the pressure balance between the pulsar and Be star wind (Tavani 1994 ApJ 433 L37). Hence PSR B1259-63 is modelled as a TIME VARIABLE PLERION and may well represent the ``missing link'' in the evolution of massive stellar binaries, being a likely progenitor of an accreting Be X-ray Binary. The extended lifetime of ISO means that we now have a unique opportunity to fully map the Be star disk (a fundamental component of the shock model) close to periastron passage. The SWS data will form part of a comprehensive multi-wavelength data set (X-ray from ASCA and SAX, Optical, Near Infrared and Radio from ground based observatories). Sadly, ISO ASCA and SAX will not be available for the next periastron passage so this represents the ONLY OPPORTUNITY to obtain the full wavelength coverage needed to model the system.