Observing Campaign #865: Photometry and Spectroscopy of WR 140 (V1687 Cyg) through its upcoming periastron

Observing Campaigns
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See Details for Photometry and Spectroscopy of WR 140 (V1687 Cyg) through its upcoming periastron

Abstract: 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 on this bright (6.78 - 6.95 V) binary; AAVSO observers are requested to obtain UBVRIJHK photometry and spectroscopy as detailed below.

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I created a star chart with the VSP, 2° FoV. The list of stars does not contain any comp star with Ic and a single one with Rc if I go up to mag 10 in V.
Increasing up to mag 12 gives 3 more for Ic and Rc each. But of course a big gap in magnitude to V1687 Cyg.
Any chance to get some more R,I data for the bighter comp stars?
Matthias

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My equipment FOV is about 22’ and there is no Rc comp stars. Would be nice to have one to take Rc photometry.
Michel

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@Sebastian_Otero , could you ask the sequence team to find a closer star? Something within 0.5 degree might help Michel out.

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Using the several recent sequence updates adding Rc and Ic comp magnitudes to those that were missing my photometry seems a bit more variable than I’m expecting. Using the 75 as the main comp in BVRcIc. Defocused slightly and gave the filter wheel a few more seconds to move and settle before the short exposures required V1687 Cyg still seems more variable from night to night than I’m expecting, worse the 92 chk star I’m using isn’t very stable either. Total exposure times in my stacked images should be sampling the scintillation well enough.

Not having ever observed a WR Be star my question is should we expect night to night variations significantly larger than the range given in VSX especially for Rc and Ic?

Jim (DEY)

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Hi,
How do we submit spectra ofV1687 Cyg (WR140)? I will submit H-alpha (656.28 nm) to AVSpec-is there a dropbox or another preferred way to submit spectra?
Thanks
Richard Brown

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my email is lacienega@hotmail.com
Richard

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Hi Richard,
Submitting to AVSpec is the preferred way to submit spectra for this campaign. Thanks for asking, and for observing V1687 Cyg!
Good observing,
Elizabeth Waagen, AAVSO HQ