[vsnet-const 9] Re: V449 Sco

[Chris Lloyd <cl@ast.star.rl.ac.uk>]

I'm sorry to be the bringer of bad news but I can find no believable 
periodic variation in V449 Sco. Part of the problem is that the 
observations have a strong 1-day aliasing problem and the best (used 
loosely) periods all lie close to one day, with others appearing with 
frequencies of 1/2, 1/3, 2/3 etc cycles per day. If the period is very 
close to one day then a single observer may not see any variation for a 
whole season, if the eclipse occurs at an unfavourable time of the day. 
However, I have my doubts that this is the problem here. I strongly 
suspect that it's not variable, at least, not at this level.

The Tycho epoch photometry shows a range of 0.3 mag, which seems a bit
large, but I can find no periods here either. The best period from the
visual photometry is invisible in the Tycho data and so is the proposed
13.7 day period.  However, it is possible to find periods which produce
large gaps in the phase diagram of the Tycho photometry, so an eclipse may
be missed, but this is grasping at straws. 

Sebastian noted that John Isles' photometry showed a large range which was
unlikely to be do to observational errors. However, apart from two
outliers John's observations are practically identical in range to the
other visual observations. John's photometry is also inconsistent with the
13.7 day period, and I must say that I see no evidence of a 13.7 day
period in the original data either. 

Sebastian also noted that one of the comparison stars is a low amplitude
variable, so it is possible that we have been led to this position by a
combination of the usual observational errors, personal bias, a variable 
comparison star and bad luck. 

In the light of the Tycho photometry it is not clear to me what any new
visual photometry could do. If any new observations are made they must be
from several longitudes and over a range of hour angles to overcome
aliasing problems. Even then I doubt that there would be any compelling
evidence, and anything found would have to run the gauntlet of the Tycho
data. The best solution would be for someone with a CCD to make a couple
of long runs and a scattering of more isolated observations, and this
would probably settle the issue. 

Cheers Chris

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