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

May 2017 • 2017MNRAS.467.2494P

Authors • Pablo, Herbert • Richardson, N. D. • Fuller, J. • Rowe, J. • Moffat, A. F. J. • Kuschnig, R. • Popowicz, A. • Handler, G. • Neiner, C. • Pigulski, A. • Wade, G. A. • Weiss, W. • Buysschaert, B. • Ramiaramanantsoa, T. • Bratcher, A. D. • Gerhartz, C. J. • Greco, J. J. • Hardegree-Ullman, K. • Lembryk, L. • Oswald, W. L.

Abstract • 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 (P_orb = 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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2017MNRAS.467.2494P
• PDF https://academic.oup.com/mnras/pdf-lookup/doi/10.1093/mnras/stx207
• PREPRINT http://arxiv.org/abs/1703.02086
• ELECTR https://doi.org/10.1093%2Fmnras%2Fstx207