J-band spectroscopy of cataclysmic variables |
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| Authors: | S. P. Littlefair V. S. Dhillon Steve B. Howell David R. Ciardi |
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| Affiliation: | Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH; Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA; Department of Astronomy, University of Florida, Gainesville, FL 32611, USA |
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| Abstract: | We present time-resolved, J ‐band (1.025–1.340 μm) infrared spectra of the short-period dwarf novae (DNe) WZ Sge and VY Aqr, and single spectra of the short-period DN EF Peg and the nova-like variable PX And. There is some evidence in the spectra of VY Aqr and EF Peg that we have detected the secondary star, both in the continuum slope and also through the possible presence of spectral features. The spectra of WZ Sge and PX And, on the other hand, show no evidence for the secondary star, with upper limits for its contribution to the J ‐band light of 10 and 20 per cent respectively. The spectral type of the secondary in WZ Sge is constrained to be later than M7.5V. Using skew mapping, we have been able to derive a value for the radial velocity semi-amplitude of the secondary star in VY Aqr of K R =320±70 km s−1, which in conjunction with K W from Thorstensen & Taylor gives a mass ratio of q =0.15±0.04. |
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| Keywords: | stars: individual: WZ Sge stars: individual: VY Aqr stars: individual: EF Peg stars: individual: PX And novae, cataclysmic variables infrared: stars |
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