Dynamo effect in the double periodic variable DQ Velorum

TL;DR

This paper investigates the magnetic dynamo hypothesis for the long period of the binary system DQ Velorum, modeling its evolution and matching observed properties to understand the origin of its 189-day cycle.

Contribution

It introduces a dynamo-based model to explain the long period of DQ Velorum and predicts dynamo activity variations during mass transfer epochs.

Findings

Model accurately reproduces current system state

Predicts increased dynamo number during high mass transfer

Long/orbital period ratio matches observations at current age

Abstract

DQ Velorum is a galactic double periodic variable (DPV), this system is a semi-detached binary comprised of a B-type gainer and an A-type donor star plus an extended accretion disc around the gainer. The system also presents an orbital period of $6.08337$~days and a long period of $189$~days whose origin is still under debate. Here we studied the possibility that this period may be driven by a magnetic dynamo investigating the entire evolution of the system. The model matches in a very good way the current state of the system and it can potentially be used to describe the evolution of DQ Velorum. It also predicts an increase of the dynamo number of the donor during epochs of high mass transfer in this system, and a theoretical long/orbital period ratio very close to the observed one at the present system age.