We report the results of long observing campaigns on two novalike variables:V442 Ophiuchi and RX J1643.7+3402. These stars have high-excitation spectra,complex line profiles signifying mass loss at particular orbital phases, andsimilar orbital periods (respectively 0.12433 and 0.12056 d). They arewell-credentialed members of the SW Sex class of cataclysmic variables. Theirlight curves are also quite complex. V442 Oph shows periodic signals withperiods of 0.12090(8) and 4.37(15) days, and RX J1643.7+3402 shows similarsignals at 0.11696(8) d and 4.05(12) d. We interpret these short and longperiods respectively as a "negative superhump" and the wobble period of theaccretion disk. The superhump could then possibly arise from the heating of thesecondary (and structures fixed in the orbital frame) by inner-disk radiation,which reaches the secondary relatively unimpeded since the disk is notcoplanar. At higher frequencies, both stars show another type of variability:quasi-periodic oscillations (QPOs) with a period near 1000 seconds. Underlyingthese strong signals of low stability may be weak signals of higher stability.Similar QPOs, and negative superhumps, are quite common features in SW Sexstars. Both can in principle be explained by ascribing strong magnetism to thewhite dwarf member of the binary; and we suggest that SW Sex stars areborderline AM Herculis binaries, usually drowned by a high accretion rate. Thiswould provide an ancestor channel for AM Hers, whose origin is stillmysterious.
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