Hi WR gang!
Just for information to everybody: Tony Moffat sent the attached email to all participants of our WR 140 campaign (Lothar: Your email was wrong but I corrected that and I assume he will send it again).
I believe we are now I very serious business and need do make our contribution.
Dear WR140 afficionados (Robin, UK; Jose, Portugal; Lothar & Berthold, Germany):
Please allow me to express my extreme gratitude to all of you for offering to participate in an international
campaign on this star in which I am involved with 6 other professional astronomers. We met last October
at ESA near Madrid for 3 days to iron out a strategy. I mentioned to them (via Thomas Eversberg's wonderful source of information) that you as amateurs are keenly invoved. This was viewed with great enthusiasm by all.
A few days ago, Thomas forwarded to me another excellent spectrum that Robin took. This is very important,
because this time next year will be the most critical period, i.e. close to periastron passage, when the HeI
5876 line shows an excess emission (only about 10% of the underlying intensity) component arising in the enhanced shock cone due to the colliding winds between the stellar pair. According to the
previous periastron passage in Feb 2001, this excess is only visible for about 2 months, centered on about 2 weeks after periastron passage. Ideally, we need almost daily monitoring in spectroscopy from early December 2008 through end of February 2009, with less frequent monitoring before and after those dates. This makes it
very tough, as you know, for 2 reasons: northern climates are not the best at this time of year and the star
is difficult to observe then, since it is normally a summer object (Cygnus). But this challenge makes it all the
more fun in a sense! It is also why I have contacted several observatories around the world (India, US, Canada)
to increase the chances of getting good coverage. Of course, it would be best with one single instrument, but
weather will more than likely prevent that from happening. If only there was a spectrograph in space available for 3-4 months of spectroscopic monitoring!
BTW if any of you can also observe the very strong HeI 10830A line, that would be great. Most CCDs are nearly dead at those wavelengths, but at larger telescopes, it is possible to get it, if one does not have a NIR spectrograph.
Presently, we are about 6 months away from the point in time when WR140 culminates in the sky in the middle of the night. I.e., it is the worst time now! However, it also means that one can observe it twice per night, once
at the very beginning and again at the very end of the night. In a week or two, it will only be observable at the end of the night (just as a couple of weeks ago it was only observable at the beginning). This makes for another inconvenient challenge, i.e. staying up all night or getting up early enough to check for clear skies and then observing it. But I hope you will consider doing this. This year is a good time to practise, to see if it will work
next year, when it really counts between Dec 2008 and Feb 2009.
If you have any questions or comments, please do not hesitate to ask, preferably using the "reply all" button.
All the best,
Département de physique
Université de Montréal
C.P. 6128, Succursale Centre-Ville
Montréal, QC, H3C 3J7, Canada