[vsnet-alert 11220] re ASAS 150946-2147.7 quiescent period update

[eruptors at Safe-mail.net]

http://i44.tinypic.com/msccvo.jpg  ~ 0.35 d

http://i40.tinypic.com/2jax5k6.jpg  ~ 0.70 d

Had a smidget of feedback on these periods, this apparently looks to be the likely period(s), and not alias(es).


Now, after ourburst is over these could do with more rigorous examination photometrically at precisions better then the wide field ASAS3 survey's +/- 0.1 V ish range to tie things down a bit tighter.

There're reflection effect possibilities, ~ 0.35 day period, rotational variation seems a little unlikely if the brighter star at quiescence is a late A main sequence star as the Japanese team suggest from their spectral examination, 0.35 days is a bit fast for that, quite a bit.

If the thing was a late A main sequence object going around a 'black hole', well, it could simply be ELL, ellipsoid variation of the A star at 0.70 days.  Or there could be an EW contact binary pair and some third object, or one of the contact binary pair somehow makes outbursts or has an accretion disc.

Or farfetched but not entirely discountable combinations and the like, ie the morphology of the lightcurve might owe more to reality than to data being interpreted near the noise level.  Or not.

Or it could still be line of sight coincidence, it's not a completely unavoidable possibility, CVs with field neighbours within an arcsec or two not easily resolved are known, often with caveats re not mistaking the neighbour for an outburst onset... ...imagine if said neighbour had the same separation but was eleventh magnitude.

Basically it will be time to observe, with steady time series campaigns, the object after outburst, sufficient nights, probably also sufficient longitudes (aliasing avoiding) to plot the folded lightcurve to better precision than +/- 0.1 V.

If done in several photomteric passbands there is the possibility of Wilson Devinney attempts at modelling the system, some folk can do that themselves, some folk, including amateurs, have copies of and know how to use programs for doing it.

If any professionals are kind enough to throw in a smattering of radial velocities, and there are those that do rabidly do radial velocity work on CVs, albeit faint ones, in quiescence, better still.

But this is all post outburst, when it's likely to be forgotten about, and not likely to be mentioned on what amounts to the cataclysmic varaible equivalent of Twitchers' mail list.

Hopefully folk will remember.  If V1129 Cen and this object are physical objects, contact binaries with outbursts, they're new and that bit different and probably astrophysically informative.  And warrant photometric follow up, but this time moreso after going BOOM!

Cheers

John