TY - JOUR
T1 - Superhumps in cataclysmic binaries. XXIII. V442 ophiuchi and RX J1643.7+3402
AU - Patterson, Joseph
AU - Fenton, William H.
AU - Thorstensen, John R.
AU - Harvey, David A.
AU - Skillman, David R.
AU - Fried, Robert E.
AU - Monard, Berto
AU - O'Donoghue, Darragh
AU - Beshore, Edward
AU - Martin, Brian
AU - Niarchos, Panos
AU - Vanmunster, Tonny
AU - Foote, Jerry
AU - Bolt, Greg
AU - Rea, Robert
AU - Cook, Lewis M.
AU - Butterworth, Neil
AU - Wood, Matt
PY - 2003
Y1 - 2003
N2 - 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, and similar orbital periods (respectively, 0.12433 and 0.12056 days). They are well-credentialed members of the SW Sex class of cataclysmic variables. Their light curves are also quite complex. V442 Oph shows periodic signals with periods of 0.12090(8) and 4.37(15) days, and RX J1643.7+3402 shows similar signals at 0.11696(8) and 4.05(12) days. We interpret these short and long periods, respectively, as a "negative superhump" and the wobble period of the accretion disk. The superhump could then possibly arise from the heating of the secondary (and structures fixed in the orbital frame) by inner-disk radiation, which reaches the secondary relatively unimpeded since the disk is not coplanar. At higher frequencies, both stars show another type of variability: quasi-periodic oscillations with a period near 1000 s. Underlying these strong signals of low stability may be weak signals of higher stability. Similar quasi-periodic oscillations, and negative superhumps, are quite common features in SW Sex stars. Both can in principle be explained by ascribing strong magnetism to the white dwarf member of the binary; and we suggest that SW Sex stars are borderline AM Herculis binaries, usually drowned by a high accretion rate. This would provide an ancestor channel for AM Hers, whose origin is still mysterious.
AB - 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, and similar orbital periods (respectively, 0.12433 and 0.12056 days). They are well-credentialed members of the SW Sex class of cataclysmic variables. Their light curves are also quite complex. V442 Oph shows periodic signals with periods of 0.12090(8) and 4.37(15) days, and RX J1643.7+3402 shows similar signals at 0.11696(8) and 4.05(12) days. We interpret these short and long periods, respectively, as a "negative superhump" and the wobble period of the accretion disk. The superhump could then possibly arise from the heating of the secondary (and structures fixed in the orbital frame) by inner-disk radiation, which reaches the secondary relatively unimpeded since the disk is not coplanar. At higher frequencies, both stars show another type of variability: quasi-periodic oscillations with a period near 1000 s. Underlying these strong signals of low stability may be weak signals of higher stability. Similar quasi-periodic oscillations, and negative superhumps, are quite common features in SW Sex stars. Both can in principle be explained by ascribing strong magnetism to the white dwarf member of the binary; and we suggest that SW Sex stars are borderline AM Herculis binaries, usually drowned by a high accretion rate. This would provide an ancestor channel for AM Hers, whose origin is still mysterious.
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U2 - 10.1086/344587
DO - 10.1086/344587
M3 - Article
AN - SCOPUS:0041667765
SN - 0004-6280
VL - 114
SP - 1364
EP - 1381
JO - Publications of the Astronomical Society of the Pacific
JF - Publications of the Astronomical Society of the Pacific
IS - 802
ER -