WR140 is a binary system comprising a WC7 Wolf-Rayet star and an O5 companion. Both have extremely fast stellar winds (up to 3000 km/s) that carry away staggering amounts of material: ~2 trillion tonnes per millisecond for the former and ~200 billion tonnes per millisecond for the latter.
At closest approach, the winds of these stars collide with maximum energy releasing vast amounts of radiation from X-rays to radio waves.
Here is a great animation of the orbit of the two stars. The teal color cone is the surface where the two winds collide.
To the best of my knowledge, periastron passage occurs some time today December, 18 2016.
Thanks to a tip from Robin Leadbeater, I have been following this system with my simple Star Analyzer diffraction grating since November 25, 2016.
This article shows how the CIII peak at 569.6 nm increased around periastron passage (see Figure 2, page 16).
Here is a comparison of the spectra I took on 11/25 (in blue) with one taken on 12/05 (in black with red dots for data points). At this point the stars were too far apart and I couldn't detect any increase in CIII emission around 570 nm.
Here is a more recent comparison of the spectra I took on 11/25 (in blue) with one taken on 12/15 (in black with red dots for data points). It's possible the results are an artifact of my crude data processing, but they are consistent with the predicted increase in CIII emission around 569.6 nm due to the closer approach of the stars and the more energetic collision of their stellar winds. Note all the red dots around 570 nm that are above the blue line.
Hopefully I'll be able to continue to observe this fascinating system.
Edited by Organic Astrochemist, 18 December 2016 - 01:51 AM.