Optical Photometry of WR140 as the Dust Formed During the 2016 Periastron Passage

TL;DR

This study analyzes optical photometry data of WR140 following its 2016 periastron, revealing optical dips likely caused by localized dust clumps, and compares observations with dust production models.

Contribution

It provides new optical light curves of WR140 post-2016 periastron and links optical dips to dust clump formation in the dust shell.

Findings

Optical dips are likely caused by dust clumps.

Optical light curves show cycle-to-cycle variations.

Comparison with models supports dust clump hypothesis.

Abstract

The colliding wind binary WR140 produces dust in its shocked gas every periastron passage. While the infrared light curve is very repeatable, there are noticeable changes every cycle in the optical time-series photometry. In the phases following periastron, there are optical dips in the light curve that were postulated to be caused by localized clumps in the dust produced in our line of sight. We report on the B and V-band light curves that were recorded by the American Association of Variable Star Observers (AAVSO) after the 2016 periastron event and briefly discuss comparisons to geometric models of the dust production to infer that these features are likely caused by localized dust clumps in the new dust shell.