for all interested WR140 player and not to miss off-line discussions I put in our recent exchange with Jeff Hopkins/Arizona and Tony Moffat/Montréal. I know the strict use of english is difficult for some partners but obviously necessary.
Hi Jeff and Tony, great to see that this story starts!!! The paper of Sergey Marchenko et al. can also be found in the web page. With respect to language and/or knowledge problems I fully understand the penalty. However, I recommend to go into the forum anyway. It is obvoiusly essential to put together different techniques and we could learn from each other in any way. Presently I try to convince the community to change to english as ofetn as possible. Your contribution could support my efforts. Anyway, thanks again for you engagement and enthusiasm.
PS: I send my reply to Berthold Stober, KLaus Vollmann and José Ribeiro, too. They are also involved in the present activities.
Von: "Anthony Moffat" <moffat(==>)astro.umontreal.ca>
Gesendet: Mi 31.10.2007 21:28
An: Eversberg, Thomas; novatec(==>)vo.lu; Jeff Hopkins
Betreff: Re: AW: WR 140
Dear Jeff and Thomas:
I'm attaching the pertinent paper of optical observations of WR140, both spectroscopy and photometry. Note especially Fig.3 with the differential UBV photometry.
It's especially useful to get as large a wavelength base as possible, e.g. UBVRI, but note that especially the U band is most useful, because the amplitude is quite a bit larger there (due to the small duat grain size).
Also in this paper, you will find the comparison stars (2 different sets of comp and check stars) that were used.
It would be best to start doing photometry in as many bands as possible now.
Then every week or so for a while until next October 2008, when the rate should pick up, if possible. But the key period, based on the previous periastron passage is during several months just AFTER perisatron, i.e. from Jan-May 2009. (But still continuing to observe thereafter at a leisurely pace for a few months at least.)
That is when we expect the largest fluctuations on time scales of a week or so.
So best to get daily data then and even Nov-Dec 2008, if possible. It's a difficult time, since this is a summer star being observed 6 months later in winter! To get it, one has to be quick after (during, actually; the star is quite bright at V = 7.0) twilight before mid January or so, and quick before dawn thereafter (although for a while, it should be possible to get the star at both times in January!). At DEC = +40 WR140 (= HD 193793) may be difficult to get at these times at or below the
Pls don't hesitate to ask questions!
And thanks for your interest....
Cheers, Tony Moffat
----- Original Message -----
From: "Jeff Hopkins" <phxjeff(==>)hposoft.com>
To: <Thomas.Eversberg(==>)dlr.de>; <novatec(==>)vo.lu>
Sent: Wednesday, October 31, 2007 2:12 PM
Subject: Re: AW: WR 140
I checked the form, but see it is all in German. I'm pretty rusty with German so I doubt I could participate. I area of expertise is strictly photometry so while spectroscopy is of interest, I am not knowledgeable enough in that field to contribute or even appreciate the discussions.
To add WR 140 to my photometry program I will need to find suitable comparison stars. If I do BVRI CCD photometry, they will need to be in the same field. I can easily do CCD photometry on stars fainter than 12th magnitude. However, the single channel UBV work has a big problem of being able to find stars fainter than around 6th magnitude as they are washed out in the bright Phoenix night sky. So probably I would do BVRI photometry with the CCD.
When have time I will continue my research on WR 140 and see what others have done and what comparison stars were used.
Any additional information would be useful. Thanks!
Hopkins Phoenix Observatory
7812 West Clayton Drive
Phoenix, Arizona 85033-2439 U.S.A.
(623) 247-1190 (Fax)
At 05:08 -0700 10/31/2007, Thomas Eversberg wrote:
as far as I understood Tony Moffat from Montreal the pro's need everything (as usual) but to get a clear statement I will send this response as cc to Tony to get a clear idea. Tony, please give information about that.
In addition I recommend to log into our WR forum http://spektroskopie.fg-vds.de/forum/
to keep the discussion alive for everybody. In "Observations" we introduced a subforum about this star. But of course, I am also fine with this internal mail exchange.