2005A&A...440..701R

We have identified a new intermediate polar, HS 0943+1404, as part of our ongoing search for cataclysmic variables in the Hamburg Quasar Survey. The orbital and white dwarf spin periods determined from time-resolved photometry and spectroscopy are P_orb≃250min and P_spin=69.171±0.001min, respectively. The combination of a large ratio P_spin/P_orb≃0.3 and a long orbital period is very unusual compared to the other known intermediate polars. The magnetic moment of the white dwarf is estimated to be µ₁∼10³⁴G.cm³, which is in the typical range of polars. Our extensive photometry shows that HS 0943+1404 enters into deep (∼3mag) low states, which are also a characteristic feature of polars. We therefore suggest that the system is a true ``intermediate'' polar that will eventually synchronise, that is, a transitional object between intermediate polars and polars. The optical spectrum of HS 0943+1404 also exhibits a number of unusual emission lines, most noticeably NII λ5680, which is likely to reflect enhanced nitrogen abundances in the envelope of the secondary.