Eclipsing Binaries in the MOA-II Database

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dc.contributor.advisor Rattenbury, NJ en Li, Man Cheung Alex en 2019-02-25T01:37:20Z en 2019 en
dc.identifier.uri en
dc.description.abstract The present evolution of the Microlensing Observations in Astrophysics (MOA-II) project began in 2006. MOA-II monitors millions of stars simultaneously towards the densely populated regions of the Galactic bulge (GB) using a 1.8m telescope with a wide-field CCD camera and has resulted in about 100TBs of image data spanning over nine years to date. Such a large amount of data is a valuable resource for variable star research. This thesis is focused on the aspects of eclipsing binary (EB) study using the MOA-II data including identifying EBs in the MOA-II database and searching for tertiary companions in EBs via eclipse time variation (ETV) analysis. We first present the first catalogue of EBs in two MOA fields towards the GB, i.e., GB9 and GB10, in which 8733 EB candidates, mostly contact and semi-detached binaries of periods< 1 day, were identified using two MOA observational seasons’ worth of data. At this stage, we also identified three triple candidates among these 8733 EB candidates by detecting the light travel time effect (LTTE) signals in their ETV curves. A sample of 542 EBs with periods less than two days in two subfields in GB9 and GB10 - GB9-9 and G10-1 - were selected for further ETV analysis. For this sample we were able to obtain the full time series from MOA-II that spans 9.5 years. We discovered 91 EBs among these 542 EBs with detected LTTE signals suggesting the presence of tertiary companions of orbiting periods from 250 days to 28 years. The frequency of EBs with tertiary companions in our sample increases as the period decreases and reaches the value of 0.65 for contact binaries of periods < 0.3 days. If only the contact binaries of periods < 0.26 days are considered, the frequency even goes to the unit. Our results suggest that contact binaries with periods close to the 0.22-day contact binary limit are commonly accompanied by relatively close tertiary companions. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA99265149812602091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights.uri en
dc.title Eclipsing Binaries in the MOA-II Database en
dc.type Thesis en Physics en The University of Auckland en Doctoral en PhD en
dc.rights.holder Copyright: The author en
dc.rights.accessrights en
pubs.elements-id 763548 en
pubs.record-created-at-source-date 2019-02-25 en

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