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

2017; Oxford University Press; Volume: 467; Issue: 2 Linguagem: Inglês

10.1093/mnras/stx207

1365-2966

H. Pablo, Noel D. Richardson, Jim Fuller, Jason F. Rowe, A. F. J. Moffat, R. Kuschnig, Adam Popowicz, G. Handler, C. Neiner, A. Pigulski, G. A. Wade, W. W. Weiß, B. Buysschaert, Tahina Ramiaramanantsoa, A. D. Bratcher, Cody Gerhartz, Jennifer Greco, Kevin K. Hardegree-Ullman, L. Lembryk, W. L. Oswald,

Astro and Planetary Science

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 × 104.