Determine conditions for orbitally modulated LSP/RV scenarios

Determine the exact physical conditions—spanning companion properties (mass, luminosity, effective temperature), orbital geometry (inclination, separation), and circumstellar environment parameters (dust replenishment timescale, dust composition and distribution)—under which each orbitally modulated mechanism for Long Secondary Period behavior and lightcurve–radial-velocity phase relationships arises in cool evolved stars, specifically including the scenarios of occultation by companion-dragged dust clouds, dynamical dispersal producing under-densities, accretion, and irradiation-driven clearing in systems like Betelgeuse.

Background

The paper revises the prevailing binarity explanation for Long Secondary Periods (LSPs) by proposing that, in Betelgeuse, a low-mass companion modulates circumstellar dust rather than dragging a trailing cloud, consistent with the observed lightcurve–radial-velocity phase offset. The authors note that LSP stars display diverse behaviors (e.g., narrow dips, steady amplitudes, varying phase offsets), suggesting multiple distinct mechanisms may operate depending on system parameters.

They infer that companion and environmental properties likely determine whether an orbitally modulated LSP manifests via occultation, dispersal, accretion, or irradiation, and explicitly defer a systematic derivation of the precise conditions for each case to future work.