XMM-Newton observations of the Polar SDSSJ155331.12+551614.5 reveal that all the X-ray flux emerges at energies < 2 keV .
The best fit to the spectrum is with a thermal plasma with kT=0.8 keV plus a 20-90 eV black body , yielding a thermal X-ray luminosity of 8.0-9.5 \times 10 ^ { 28 } ergs s ^ { -1 } .
The low temperature and X-ray luminosity , together with the lack of variation of the X-ray flux during the observations , are all consistent with an extremely low accretion rate that puts the system in the bombardment regime of accretion , rather than accretion involving a standoff shock .
It is likely that the observed X-rays originate from the M dwarf secondary star , thus providing a base activity level for late main sequence stars in close binaries .
SDSSJ132411.57+032050.5 is detected by XMM-Newton at the faint EPIC-pn count rate of 0.0012 \pm 0.0003 giving an upper limit to the X-ray luminosity of \sim 7 \times 10 ^ { 28 } ergs s ^ { -1 } for a distance of 300 pc , which is also consistent with the above scenario .