(cba:news) Fwd: [vsnet-alert 17851] WX Ari very deep fading

Joe Patterson jop at astro.columbia.edu
Thu Oct 16 20:11:48 EDT 2014


A very low state of another VY Scl star - and one we've observed pretty 
extensively in the hign state.  This is a great target, if you can 
handle the magnitude (18th).  And if you think you can't, then... well, 
think again, at least briefly.  One theory of these stars predicts 
large-amplitude phoptmetric signals at the 3.5 hour orbital period.  I'm 
not *expecting* that, but it's possible.  Let's look.

At this brightness, unfiltered is the only reasonable choice.  You can 
use longish integrations times, since we won't be detecting short 
periods in so faint a star.

joe


-------- Original Message --------
Return-Path: <vsnet-alert-bounces at ooruri.kusastro.kyoto-u.ac.jp>



This cataclysmic variable of VY Scl type ("anti-nova") is in the very
low state on the recent survey images from MASTER-Kislovodsk robotic
telescope.

WX Ari
   20140103.649  160C  MASTER-Kislovodsk
   20140103.680  159C  MASTER-Kislovodsk
   20141012.971  184C  MASTER-Kislovodsk
   20141013.017  182C  MASTER-Kislovodsk

The recent fading episode was observed 2 years ago (September-December
2012). Eddy Muyllaert has reported unfiltered magnitudes from 16.4: to
16.8: on 2012 Sep. 21 - Oct. 15 [vsnet-alert 15008]. AAVSO data show
the further dimming to as low as 17.4 on 2012 Dec. 20 (with the
large-amplitude orbital variations from about 16.8 to 17.4).

Catalina Sky Survey light curve indicates that after recovering from
the low state the star has reached higher-than-normal level peaking at
14.4 on 2013-09-16, then started fading again:
http://nesssi.cacr.caltech.edu/catalina/20010316/103161090154100096p.html

The current fading episode appears to be the deepest recorded.
Magnitude range in AAVSO VSX is 14.5 - <16.7 CV, orbital period is
3.344 hr.

Denis Denisenko
Member of MASTER team at SAI MSU



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