Surface activity of the G dwarf primary in the quaternary star system V815 Her

TL;DR

This paper studies the magnetic activity and surface spots of the G dwarf star in the complex V815 Her system, revealing its multi-star structure and providing the first Doppler images of its surface.

Contribution

It offers the first Doppler imaging of the G dwarf's surface and clarifies the system's quadruple-star configuration with orbital solutions.

Findings

V815 Her is a four-star system with two close binaries.

Long-term spot activity observed on the G dwarf.

First Doppler images of the G dwarf's surface provided.

Abstract

We investigate the magnetic activity of the G dwarf primary star in the multiple system V815 Herculis. Recently, TESS Sector 26 data have revealed that V815 Her is in fact a four-star system consisting of two close binaries in a long-period orbit. We give preliminary orbital solution for the long-known but unseen "third body" V815 Her `B', which is itself a close eclipsing binary of two M dwarfs. Long-term spot activity of the G dwarf is presented along with the very first Doppler image reconstructions of its spotted surface.