[vsnet-campaign-news 304] VSNET Weekly Campaign Summary

Tue Jan 31 21:36:05 JST 2006

VSNET Weekly Campaign Summary

*** Headlines ***

Another new ASAS dwarf nova! WZ Sge-type ? ----- ASAS 102522-1542.4 
A new WZ Sge-type object! ----- ASAS 023322-1047.0

*** Last week news ***

(new targets) 
  ASAS 102522-1542.4    (RA = 10h25m22s.23, Dec = -15d42'21".5)

    G. Pojmanski reported a discovery of a new object by the ASAS3V
  system.  The object was first recorded on an image taken on Jan 26
  at V=12.219.  It was faint on Jan 23 (V<14).  A faint object was
  listed in the USNO_B1 catalog at b1=19.32.  This may be a quiescent
  counterpart of this new object (vsnet-alert 8821).
    H. Maehara performed time-series photometry on Jan 27, and detected
  small periodic modulations.  The period of them is about 0.03 d, and
  if they are double-peaked humps, the period is about 0.06 d.  
  He proposed that they seems to be early superhumps and this object
  is a WZ Sge-type dwarf nova, now in a very rare superoutburst
  (vsnet-alert 8824).  On Jan 28, he again obtained a light curve,
  which showed clear ordinary superhumps with amplitudes of 0.2mag.  
  The period of superhump is around 0.055 days.  This period
  may support the early superhump scenario of the Jan 27 humps
  (vsnet-alert 8825).  P. C. Sherrod confirmed the periodic
  modulations on Jan 29 (vsnet-alert 8826).  Combining the light
  curves on Jan 28 and 29, H. Maehara revised the period to be 0.063 d
  (vsnet-alert 8828). 
    H. E. Bond et al. performed spectroscopic observations using the
  SMRATS 1.5m telescope.  The resultant spectra showed broad, shallow
  absorption lines of the Balmer series and He I 4471 A.  This is
  typical of a dwarf nova at maximum light, and confirms ASAS
  J102522-1542.4 as a new member of the dwarf-nova class 
  (vsnet-alert 8830).

  NSV 18024             (RA = 08h44m34s.05, Dec = -37d57'52".5)

    S. Otero reported an outburst of this poorly studied object
  detected by P. Wils.  Based on the ASAS database, he reported an
  outburst cycle of this object is about 490 d.  The current outburst
  started Jan 21, and outbursts usually last about 2 weeks.  The
  object is classified as a G8-K0 star.  Amplitude is between 0.1 and
  0.2 mag. and the star goes from its quiescent V= 8.13 level up to
  7.95 - 8.0  (vsnet-alert 8817).  P. Wils reported that a ROSAT X-ray
  source, 1RXS J084433.5-375738, is only 16" distant from NSV 18024,
  which implies a kind of outbursting object (vsnet-alert 8820).
  S. Kiyota performed multi-color photometry on Jan 27; B=8.72,
  V=7.98, Rc=7.66, and Ic=7.17 (vsnet-alert 8829).  The V-Rc=0.32 is
  significantly bluer than the quiescent G8-K0 star.

  BZ Cir                (RA = 14h54m15s.206, Dec = -68d16'18".68)

    An outburst of BZ Cir was reported by B. Monard on Jan 21 
  (14.6CR mag; vsnet-alert 8814).

  V504 Cen              (RA = 14h12m49s.11, Dec = -40d21'37".1)

    B. Monard reported a confirmation of a fading trend of V504 Cen 
  (vsnet-alert 8814).

(old targets)
  ASAS 023322-1047.0    (RA = 02h33m21s.41, Dec = -10d47'04".09)

    Using time-series data taken by H. Maehara, S. Kiyota, and
  K. Nakajima taken on Jan 22-25, H. Maehara performed a period
  analysis and reported a detection of early superhumps having a
  period of 0.05491(5) days.  The detection of the early superhumps
  revealed that this new object is a rare member of WZ Sge-type dwarf
  novae (vsnet-alert 8815).  The periodic variations were also
  confirmed by P. C. Sherrod (vsnet-alert 8816).  P. C. Sherrod
  reported a fading of the object in Jan 30 (vsnet-alert 8831).
    Results of the astrometry by C. Sherrod confirmed that the
  proposed faint star in the USNO B1.0 is the quiescent counterpart of
  this new object (vsnet-alert 8813, 8819).

  TT Ari                  (RA = 02h06m53s.09, Dec = +15d17'43".0)

    I.L. Andronov et al. reported that the character of variability of
  TT Ari has recently been changed again.  Recent light curves shows
  both negative superhumps and QPOs. The periodogram shows the higher
  semi-amplitude of superhumps (77+-5mmag) then  that of the QPOs
  (50+-4mmag) (vsnet-campaign 1642).

*** General information ***

  ASAS 023322-1047.0
    Light curve generated by H. Maehara:
      http://www.cetus-net.org/ftp/light_curves/asas0233_early_superhump.png

  ASAS 102522-1542.4
    Light curve by the ASAS3 database:
      http://www.astrouw.edu.pl/cgi-asas/asas_disc/102522-1542.4,3755
                                              [vsnet-alert 8812]
    Light curve obtained by H. Maehara:
      http://www.cetus-net.org/ftp/light_curves/asas102522-1542.4-20060127.png
                                              [vsnet-alert 8824]
      http://www.cetus-net.org/ftp/light_curves/asas023322-1047.0-20060128.png
                                              [vsnet-alert 8825]
      http://www.cetus-net.org/ftp/light_curves/asas102522-1542.4-20060129.png
                                              [vsnet-alert 8828]

(This summary can be cited.)	

Regards,
Makoto Uemura
Hiroshima University