We observed the accreting white dwarf 1E1339.8+2837 ( 1E1339 ) in the globular cluster M3 in Nov. 2003 , May 2004 and Jan. 2005 , using the { \it Chandra } ACIS-S detector .
The source was observed in 1992 to possess traits of a supersoft X-ray source ( SSS ) , with a 0.1-2.4 keV luminosity as large as 2 \times 10 ^ { 35 } erg s ^ { -1 } , after which time the source ’ s luminosity fell by roughly two orders of magnitude , adopting a hard X-ray spectrum more typical of CVs .
Our observations confirm 1E1339 ’ s hard CV-like spectrum , with photon index \Gamma = 1.3 \pm 0.2 .
We found 1E1339 to be highly variable , with a 0.5-10 keV luminosity ranging from 1.4 \pm 0.3 \times 10 ^ { 34 } erg s ^ { -1 } to 8.5 ^ { +4.9 } _ { -4.6 } \times 10 ^ { 32 } erg s ^ { -1 } , with 1E1339 ’ s maximum luminosity being perhaps the highest yet recorded for hard X-ray emission onto a white dwarf .
In Jan. 2005 , 1E1339 displayed substantial low-energy emission below \sim 0.3 keV .
Although current { \it Chandra } responses can not properly model this emission , its bolometric luminosity appears comparable to or greater than that of the hard spectral component .
This raises the possibility that the supersoft X-ray emission seen from 1E1339 in 1992 may have shifted to the far-UV .