Dipolar magnetic fields in binaries and gravitational waves

TL;DR

This paper investigates how magnetic fields in white dwarf binaries can cause detectable changes in gravitational wave signals observed by LISA, challenging the assumption that magnetic effects are negligible.

Contribution

It demonstrates that magnetic fields induce a secular drift in orbital parameters, affecting gravitational waveforms in a measurable way.

Findings

Magnetic fields cause a secular drift in the argument of periastron.

Magnetic effects can modify gravitational waveforms detectable by LISA.

Magnetic influence on binary orbits is more significant than previously assumed.

Abstract

The LISA mission will observe gravitational waves emitted from tens of thousands of galactic binaries, in particular white dwarf binary systems. These objects are known to have intense magnetic fields. However, these fields are usually not considered as their influence on the orbital and rotational motion of the binary is assumed for being too weak. It turns out that magnetic fields modify the orbits, in particular their geometry with respect to the observer. In this work, we revisit the issue, assuming magnetostatic approximation, and we show how the magnetic fields within a binary system generate a secular drift in the argument of the periastron, leading then, to modifications of the gravitational waveforms that are potentially detectable by LISA.