HIP10680/HIP10679: a visual binary in the $\beta$ Pictoris Association with the fastest rotating member

TL;DR

This study monitors a wide binary system in the $eta$ Pictoris Association, revealing that its components have different rotation periods and axes alignment, with implications for their formation and evolution.

Contribution

First detailed photometric monitoring of the HIP10680/HIP10679 binary revealing their rotation periods, axis alignment, and potential evolutionary differences.

Findings

HIP10680 has a rotation period of 0.2396 days.

HIP10679 has a rotation period of 0.777 days.

The rotation axes of both stars are aligned with an inclination of about 10 degrees.

Abstract

We present the results of a multi-filter photometric monitoring of the wide binary HIP10680/HIP10679. We found both component to be variable with amplitude up to $\Delta$V = 0.03 mag in the case of HIP10680 and $\Delta$V = 0.07 mag in the case of HIP10679. We could measure the rotation periods P = 0.2396d of the hotter F5V component HIP10680 and P = 0.777d of the cooler G5V component HIP10679. We found that the rotation axes of both components are aligned with an inclination $i$ = $\sim$ 10$^{\circ}$. Although the two components have a mass difference not larger than 15%, they exhibit a significant difference between their rotation periods. Such difference may arise either from different initial rotation periods or to different disc life times. For instance, the slower rotating component HIP 10679 hosts a well know debris disc.