  We have discovered with the Wide Field Cameras on board BeppoSAX the weak
transient X-ray source SAXJ2239.3+6116 whose position coincides with that of
4U2238+60/3A2237+608 and is close to that of the fast transient AT2238+60 and
the unidentified EGRET source 3EG2227+6122. The data suggest that the source
exhibits outbursts that last for a few weeks and peak to a flux of 4E-10
erg/s/cm2 (2-10 keV) at maximum. During the peak the X-ray spectrum is hard
with a photon index of -1.1+/-0.1. Follow-up observations with the Narrow-Field
Instruments on the same platform revealed a quiescent emission level that is
1E+3 times less. Searches through the data archive of the All-Sky Monitor on
RXTE result in the recognition of five outbursts in total from this source
during 1996-1999, with a regular interval time of 262 days. Optical
observations with the KPNO 2.1 m telescope provide a likely optical
counterpart. It is a B0 V to B2 III star with broadened emission lines at an
approximate distance of 4.4 kpc. The distance implies a 2-10 keV luminosity in
the range from 1E+33 to 1E+36 erg/s. The evidence suggests that SAXJ2239.3+6116
is a Be X-ray binary with an orbital period of 262 days.

Astrophysics