Theta Muscae - first attempts

[Paul Luckas]

I'm commissioning a Spectra-L200 using the bright Wolf-Rayet star Theta Mus. The attached shows evidence of the expected shift in the CIII region over the period of the observations.

However, I'm not confident of my data for a variety of reasons. First, I performed some hardware adjustments of the spectroscope after June 6 and June 15. I'm also very inexperienced in spectroscopy analysis - calibration, normalising and scaling etc - and noticed that my neon calibration images are over-saturated (I'm also lacking calibration lines in the region of interest).

(A big thanks to Ken Harrison for his guidance in getting me up and running using the Spectra-L200 and BASS so quickly).

Comments or suggestions gratefully received.

ThetaMus_06-12-14-15-22-24-25.jpg (172.94 KiB) Viewed 4998 times

Reference: (Hill, G. M., et al. "Modelling the spectra of colliding winds in the Wolf-Rayet WC7+ O binaries WR 42 and WR 79." Monthly Notices of the Royal Astronomical Society 318.2 (2000): 402-410.

[Robin Leadbeater]

Very interesting Paul,

The repeatability rest of the spectrum looks good so I would expect the CIII line variation to be real. Variations are certainly detectable in the wind of WR stars though this is the most extreme I have seen. (This is not a target I can reach though from here)

WR winds are the subject of study by the Pro-Am ConVento team.
http://www.stsci.de/convento/
You can see some examples of variation in WR134I measured in preparation for a campaign run last year. (The results are being analysed and not yet published)
http://spektroskopieforum.vdsastro.de/d ... hp?id=4827

Cheers
Robin

[Robin Leadbeater]

Also to check that what you are seeing is real, what does your reference star spectra look like in this region and is there any sign of features in the flat that might not have been corrected accurately?

Cheers
Robin

[Ken Harrison]

http://articles.adsabs.harvard.edu/cgi- ... etype=.pdf

Hill, Moffat and St Louis studied this system and these lines back in 2002.

[Robin Leadbeater]

Good find Ken,

Tony Moffat is a world expert on these stars and one of the pros on the ConVento group. A binary WR/O star with such short period and large RV swing looks like great southern target for medium resolution spectroscopy.

Cheers
Robin