# $\varepsilon$ Lupi: measuring the heartbeat of a doubly-magnetic massive binary with BRITE-Constellation

## TL;DR

This study analyzes the doubly-magnetic massive binary $$ Lupi using BRITE-Constellation data, revealing heartbeat variations, gravity mode pulsations, and providing detailed orbital and stellar parameters to compare with models.

## Contribution

It presents the first detailed orbital solution and characterization of $$ Lupi, including empirical masses, radii, and pulsation analysis, highlighting the system's unique magnetic and pulsational properties.

## Key findings

- Detected heartbeat variation in $$ Lupi from photometry.
- Determined empirical stellar masses and radii through combined data.
- Identified gravity mode pulsations consistent with SPB stars.

## Abstract

$\varepsilon$ Lupi A is a binary system consisting of two main sequence early B-type stars Aa and Ab in a short period, moderately eccentric orbit. The close binary pair is the only doubly-magnetic massive binary currently known. Using photometric data from the BRITE-Constellation we identify a modest heartbeat variation. Combining the photometry with radial velocities of both components we determine a full orbital solution including empirical masses and radii. These results are compared with stellar evolution models as well as interferometry and the differences discussed. We also find additional photometric variability at several frequencies, finding it unlikely these frequencies can be caused by tidally excited oscillations. We do, however, determine that these signals are consistent with gravity mode pulsations typical for slowly pulsating B stars. Finally we discuss how the evolution of this system will be affected by magnetism, determining that tidal interactions will still be dominant.