OO Aquilae: a solar-type contact binary with intrinsic light curve changes

Abstract

New multi-color photometry of the solar-type contact binary OO Aql was obtained in 2012 and 2013, using the 60 cm telescope at Xinglong Station of the National Astronomical Observatories, Chinese Academy of Sciences. From two sets of light curves LC1 and LC2, photometric models were performed by using the 2003 version of the Wilson-Devinney code. The overcontact factor of the binary system was determined to be f = 37.0(±0.5)%. The intrinsic variability of this binary occurs in light maxima and minima, which could result from a possible third component and magnetic activity of the late type components. Based on all available light minimum times, the orbital period may change in a complicated mode, i.e., sudden period jumps or continuous period variations. The period of OO Aql may possibly undergo a secular period decrease with a rate of dP/dt = −3.63(±0.30) × 10−8 d yr−1, superimposed by two possible cyclic variations in the O – C curve. The long-term period decrease may be interpreted as conserved mass transfer from the more massive component to the less massive one. The 21.5-yr oscillation may be attributed to cyclic magnetic activity, and the 69.3-yr one may result from the light-time effect of an unseen tertiary body.

A photometric-spectroscopic study of the infrared-excess eclipsing binary V2364 Cyg

“…The noticeable variation with time may result from cool-spot activity on the convective envelope. This situation occurs in other contact binaries, such as GU Mon (Yang et al 2019), GN Boo (Wang et al 2015), OO Aql (Li et al 2016), V410 Aur (Luo et al 2017) and DZ Psc (Yang et al 2013).…”

Mass transfer and possible third-body effect on the period variations of the near-contact binary CN And

“…In view of the apparent parabolic trend of (O − C) 1 values, we firstly adopt a quadratic polynomial to fit them. A weighted least-squares method yields the following nonlinear ephemeris Min.I = 2453339.15915(37) + 0.462790035( 46 ware PERIOD04 (Lenz 2004, Yang et al 2012, Li et al 2016. The power spectrum is displayed in Figure 2, where a significant peak is located at the frequency of f = 9.1176 × 10 −5 d −1 .…”

Long-term Optical Monitoring of the TeV BL Lacertae Object 1ES 2344 + 514

“…The parameters of the seven CLEANest components are listed in Column (5) and Column (7) of Table 5. In addition, we calculated the signal-to-noise ratio (S/N) of each CLEANest component using the software PERIOD04 (Lenz 2004;Yang et al 2012;Li et al 2016), and we list the calculation results in Table 5, Column (6). The period analysis results using DCDFT +CLEANest for the R-band data are shown in Figure 6.…”