A Tale of Two Circularization Periods

Abstract

We re-analyze the pristine eclipsing binary data from the Kepler and TESS missions, focusing on eccentricity measurements at short orbital periods to emperically constrain tidal circularization. We find an average circularization period of ∼6 days, as well as a short circularization period of ∼3 days for the Kepler /TESS field binaries. We argue previous spectroscopic binary surveys reported longer circularization periods due to small sample sizes, which were contaminated by an abundance of binaries with circular orbits out to ∼10 days, but we re-affirm their data shows a difference between the eccentricity distributions of young (<1 Gyr) and old (>3 Gyr) binaries. Our work calls into question the long circularization periods quoted often in the literature.

Tidal dissipation due to inertial waves can explain the circularization periods of solar-type binaries

“…It is interesting to briefly discuss our results in light of the recent analysis of observational data for solar-mass binaries by Zanazzi (2021), who argues against the validity of the longer P circ from observations that we have reproduced in Fig. 3.…”

“…3. The two populations identified by Zanazzi (2021) could in principle be produced by a distribution in initial stellar rotation periods, which we have shown can potentially lead to very different P circ in Fig. 5.…”

Beyond binarity in A stars II. Disentangling the four stars in the vicinity of the triple HIP 87813 within the quintuple system HJ2814

“…At the present eccentricity, it is likely that the A1-A2 system is experiencing negligible tidal dissipation within a timescale of the age of the system (∼ 200 Myr): tidal dissipation in A2 is unlikely as the circularization period of the larger sun-like stars over billions of years is likely shorter than 13 days (e.g. Zahn 1977;Duquennoy & Mayor 1991;Mathieu et al 2004;Raghavan et al 2010;Zanazzi 2021) and is a strong function of the period and radius of the star; tidal migration due to dissipation in the primary A1 A-star is largely ruled out by its fast rotation (v rot sin i = 52 km s −1 ) with a rotation period p 2days which is much shorter than the synchronization period (and the pesudo-syncronization period; Hut 1982) -if tidal dissipation was significant, synchronization would have been achieved on much shorter time scales than circularization. The low tidal dissipation in the A-star and lack of synchronization is compatible with estimates for the parameters of the system for a radiative envelope (Zahn 1977).…”