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Published March 2017 | Submitted + Published
Journal Article Open

The most massive heartbeat: an in-depth analysis of ι Orionis


ι Ori is a well-studied massive binary consisting of an O9 III + B1 III/IV star. Due to its high eccentricity (e = 0.764) and short orbital period (Porb = 29.133 76 d), it has been considered to be a good candidate to show evidence of tidal effects; however, none have previously been identified. Using photometry from the BRIght Target Explorer (BRITE)-Constellation space photometry mission, we have confirmed the existence of tidal distortions through the presence of a heartbeat signal at periastron. We combine spectroscopic and light-curve analyses to measure the masses and radii of the components, revealing ι Ori to be the most massive heartbeat system known to date. In addition, using a thorough frequency analysis, we also report the unprecedented discovery of multiple tidally induced oscillations in an O star. The amplitudes of the pulsations allow us to empirically estimate the tidal circularization rate, yielding an effective tidal quality factor Q ∼ 4 × 10^4.

Additional Information

© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 January 19. Received 2017 January 18; in original form 2016 November 18. This work is based on data collected by the BRITE Constellation satellite mission, designed, built, launched, operated and supported by the Austrian Research Promotion Agency (FFG), the University of Vienna, the Technical University of Graz, the Canadian Space Agency (CSA), the University of Toronto Institute for Aerospace Studies (UTIAS), the Foundation for Polish Science & Technology (FNiTP MNiSW) and National Science Centre (NCN). We would like to thank the computing infrastructure at Villanova for use of their cluster. NDR acknowledges postdoctoral support by the University of Toledo and by the Helen Luedtke Brooks Endowed Professorship. AFJM and HP are grateful for financial aid from NSERC (Canada) and FQRNT (Quebec).GAW acknowledges Discovery Grant support from the Natural Science and Engineering Research Council (NSERC) of Canada. AP acknowledges support from the NCN grant no. 2016/21/B/ST9/01126. JF acknowledges partial support from NSF under grant no. AST1205732 and through a Lee DuBridge Fellowship at Caltech. GH acknowledges support from the Polish NCN grant 2015/18/A/ST9/00578. The Polish participation in the BRITE project is secured by NCN grant 2011/01/M/ST9/05914. APo acknowledges NCN grant 2016/21/D/ST9/00656.

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Published - stx207.pdf

Submitted - 1703.02086.pdf


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