Proposal #554

Hello, I'm Sauro Gaudenzi, my observer code is GSAD, in support of the AAVSO alert nr 865 I request the use of a telescope to observe the binary star WR 140 ( V1687 Cyg ). Dr. Noel Richardson (Embry-RIddle Aeronautical University) writes: WR 140 (V1687 Cyg) is a long-period binary with a carbon-rich Wolf-Rayet star and a hot O supergiant. The orbital period is 7.93 yr with an eccentricity of 0.9. When the two stars come together, the shocks in the wind collision produce dust as the gas cools and our campaign will address how the optical variations work to provide the material that forms this dust. Our team has approved programs with the CHARA Array interferometer along with X-ray monitoring with NICER on the ISS. The observations here will help provide the comparisons needed to understand this Rosetta Stone of colliding winds system. A multiwavelength campaign is underway over the next several months; AAVSO observers are requested to obtain UBVRIJHK photometry and spectroscopy as detailed below. I ask that 2 or 3 photo sessions be carried out per week until February 2025 with near infrared filters j - H - K 30 shots of 20 seconds for each filter, if you do not have these filters available alternatively 2 0 3 photo sessions per week with 60 shots of 20 seconds with filter V. Thank you very much for the collaboration and have a nice day to all