Abstract:
We present analyses of new optical photometric
observations of three W UMa-type contact binaries FZ Ori,
V407 Peg and LP UMa. Results from the first polarimet-
ric observations of the FZ Ori and V407 Peg are also pre-
sented. The periods of FZ Ori, V407 Peg and LP UMa are
derived to be 0.399986, 0.636884 and 0.309898 d, respec-
tively. The O−C analyses indicate that the orbital periods
of FZ Ori and LP UMa have increased with the rate of
2.28 × 10⁻⁸ and 1.25 × 10⁻⁶d yr⁻¹ , respectively and which
is explained by transfer of mass between the components. In
addition to the secularly increasing rate of orbital period, it
was found that the period of FZ Ori has varied in sinusoidal
way with oscillation period of ∼30.1 yr. The period of os-
cillations are most likely to be explained by the light-time
effect due to the presence of a tertiary companion. Small
asymmetries have been seen around the primary and sec-
ondary maxima of light curves of all three systems, which is
probably due to the presence of cool/hot spots on the com-
ponents. The light curves of all three systems are analysed
by using Wilson-Devinney code (WD) and the fundamental
parameters of these systems have been derived. The present
analyses show that FZ Ori is a W-subtype, and V407 Peg and
LP UMa are A-subtype of the W UMa-type contact binary
systems. The polarimetric observations in B, V , R and I
bands, yield average values of polarization to be 0.26 ± 0.03,
0.22 ± 0.02, 0.22 ± 0.03 and 0.22 ± 0.05 per cent for FZ Ori
and 0.21 ± 0.02, 0.29 ± 0.03, 0.31 ± 0.01 and 0.31 ± 0.04
per cent for V407 Peg, respectively.
