SUMMARY OF PROPOSAL 42050
DR MICHAEL R GARCIA
SMITHSONIAN INSTITUTION ASTROPHYSICAL OBSERVATORY
MA USA 02138
CAMBRIDGE
60 GARDEN ST

  E-mail: GARCIA@CFA.HARVARD.EDU	Tel: 617 495 7169	Fax: 67 495 7356
  Medium: 4GBDAT

Subject: X-RAY BINARIES                                              
  Title: 4U2129+47: AN ACCRETION DISK CORONA IN A LOW STATE                              


Abstract:
 Accretion Disk Corona (ADC) have taken on an important new role our view of Low-Mass
 X-ray Binaries. They are now seen as the possible source of a wind which may
 accelerate the evolution of LMXB by 100 times. This accelerated evolution would
 allow the lifetime of LMXB to be in agreement with the postulate that LMXB are the
 progenitors of milli-second pulsars, a postulate widely held. However, our
 understanding of ADC is remarkably poor. As the main parameter effecting the
 structure of ADC is the x-ray illumination, observations of systems over a wide
 range of x-ray flux should be enlightening. 4U2129+47 offers the ONLY opportunity
 for ASCA to observe an ADC source in a low state.

 Co-Is:
   1  PAUL CALLANAN       	HARVARD                       USA       
      PCALLANAN@CFA.HARVARD.EDU	617- 495- 4141


Target Name           PRI RA        Dec        Time TC  Off GIS SIS_Cts  Obs
-------------------   --- --------  --------   ---- --  --- --- -------  ---
4U2129+47              0  322.8596   47.2900    60   N   N   P  0.01000   1