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A study of the light travel time effect in short-period MOA eclipsing binaries via eclipse timing

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posted on 10.04.2019, 09:21 by MCA Li, NJ Rattenbury, IA Bond, T Sumi, DP Bennett, N Koshimoto, F Abe, Y Asakura, R Barry, A Bhattacharya, M Donachie, P Evans, A Fukui, Y Hirao, Y Itow, K Masuda, Y Matsubara, Y Muraki, M Nagakane, K Ohnishi, T Saito, A Sharan, DJ Sullivan, D Suzuki, PJ Tristram, A Yonehara
A sample of 542 eclipsing binaries (EBs)with periods shorter than 2 days was selected from the Microlensing Observations in Astrophysics (MOA) EB catalogue (Li et al.) for eclipse-time variation analysis. For this sample, we were able to obtain a time series from MOA-II spanning 9.5 yr. We discovered 91 EBs, out of the 542 EBs, with detected light-travel-time effect signals suggesting the presence of tertiary companions with orbiting periods from 250 d-28 yr. The frequency of EBs with tertiary companions in our sample increases as the period decreases and reaches a value of 0.65 for contact binaries with periods shorter than 0.3 d. If only those contact binaries with periods < 0.26 d are considered, the frequency even goes to unity. Our results suggest that contact binaries with periods close to the 0.22-d contact binary limit are commonly accompanied by relatively close tertiary companions.


MCAL acknowledges the contribution of the New Zealand eScience Infrastructure (NeSI) high-performance computing facilities to the results of this research. New Zealand’s national facilities are provided by NeSI and funded jointly by NeSI’s collaborator institutions and through the Ministry of Business, Innovation & Employment’s Research Infrastructure programme ( NJR is a Royal Society of New Zealand Rutherford Discovery Fellow. AS is a University of Auckland Doctoral Scholar. TS acknowledges financial support from the Japan Society for the Promotion of Science (JSPS) under grant numbers JSPS23103002, JSPS24253004 and JSPS26247023. NK is supported by Grant-in-Aid for JSPS Fellows. The MOA project is supported by JSPS grants JSPS25103508 and JSPS23340064 and by the Royal Society of New Zealand Marsden Grant MAU1104.



Monthly Notices of the Royal Astronomical Society, 2018, 480 (4), pp. 4557-4577

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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Monthly Notices of the Royal Astronomical Society


Oxford University Press (OUP), Royal Astronomical Society





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