Dust formation by the colliding-wind WC5+O9 binary WR19 at periastron passage

P. M. Williams$^1$, G. Rauw$^2$ and K. A. van der Hucht$^{3,4}$

1. Institute for Astronomy, Scottish Universities Physics Alliance, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ
2. Institut d'Astrophysique et de G'eophysique, Universit'e de Li`ege, All'ee du 6 Ao^ut 17, B^at. B5c, 4000 Li`ege, Belgium
3. Space Research Organization Netherlands, Sorbonnelaan 2,NL-3584,CA Utrecht, The Netherlands
4. Astronomical Institute `Anton Pannekoek', University of Amsterdam, Kruislaan 403, NL-1098 SJ Amsterdam, The Netherlands

We present infrared photometry of the episodic dust-making Wolf-Rayet system WR19 (LS3), tracking its fading from a third observed dust-formation episode in 2007 and strengthening the view that these episodes are periodic ($P = 10.1pm0.1 y$). Radial velocities of the O9 component observed between 2001 and 2008 show RV variations consistent with WC19 being a spectroscopic binary of high eccentricity ($e=0.8$), having periastron passage in 2007.14, shortly before the phase of dust formation. In this respect, WR19 resembles the archetypical episodic dust-making colliding-wind binary system WR,140.

Reference: MNRAS
Status: Manuscript has been accepted

Weblink: ftp://ftp.roe.ac.uk/pub/pmw/wr19periastron.ps.gz


Email: pmw@roe.ac.uk