Hot colliding winds and the 2009 campaign on WR140

TL;DR

This paper discusses the characteristics of WR140, a prototypical hot colliding-wind binary, and reviews the multiwavelength observational campaign conducted during its 2009 periastron passage, highlighting the challenges and collaborative efforts involved.

Contribution

It provides an overview of WR140's properties and details the 2009 observational campaign, emphasizing multi-site and multiwavelength efforts to study this extreme system.

Findings

Successful coordination of multiwavelength observations during a short periastron window

Enhanced understanding of colliding-wind phenomena in extreme binary systems

Data collected will inform models of high-energy processes in massive binaries

Abstract

WR140 (WC7pd + O5) is often considered to be the archetype of hot, luminous colliding-wind binaries, with strong cyclic high-energy and dust-formation events. The challenge is that this system is quite extreme, with a long period (nearly an integral 7.94 years) and high eccentricity (e = 0.88). Most of the action thus occurs during the relatively short several-month interval of close periastron passage, which in the most recent 2009 January passage occurred during the northern winter months when this summer Cygnus star was least favourably placed in the sky for groundbased observation. To meet this challenge, various multiwavelength campaigns were organized at different sites and from space, mainly within several months of periastron passage 2009. Of particular interest to this workshop was the MONS optical spectroscopic effort, involving both amateur and professional astronomers at the MONS site on Tenerife from 2008 December through 2009 March. I will describe WR140 in terms of the general phenomenon of hot colliding winds and leave the new campaign details to other speakers at this workshop.