[vsnet-alert 3867] QY Per likely very rare outburst, observations requested

[Taichi Kato <tkato>]

QY Per likely very rare outburst, observations requested

   We have been informed by Mike Simonsen (AAVSO, MI USA) that the large-
amplitude SU UMa-type candidate (potentially a WZ Sge-like object)
QY Per is currently undergoing a very bright outburst.

   Recent observations:

   YYYYMMDD(UT)   mag  observer
   19991129.935  <156  (G. Poyner)
   19991201.842  <149  (G. Poyner)
   19991202.740  <150  (T. Kinnunen)
   19991203.946  <158  (G. Poyner)
   19991205.039  <158  (G. Poyner)
   19991205.919  <150  (T. Kinnunen)
   19991207.926  <156  (G. Poyner)
   19991209.030  <150  (T. Kinnunen)
   19991213.980  <152  (G. Poyner)
   19991214.860  <152  (T. Kinnunen)
   19991216.890  <150  (T. Kinnunen)
   19991219.860  <144  (T. Kinnunen)
   19991219.972  <149  (G. Poyner)
   19991228.645   135  (M. Simonsen)
   19991228.666   136  (M. Simonsen)

   Confirmatory observations are most urgently requested.

   QY Per was discovered by Hoffmeister in 1966.  Hoffmeister recorded two
outbursts (mag 14.2 on 1964 Sep. 12 and mag 16.0 on 1969 Oct. 5), the
small recorded number of outbursts already indicates the low frequency
of outbursts.  A further outburst at mag 14.9 was recorded by Risino
in 1989 (IAUC 4900).

(Extracted report from vsnet-obs 997):
--------------------------------------------------------------------------

  from Veroeff. Sternwarte Sonneberg 9, 125 (1979)

    JD      mag
  2438642  <17.0
       51   14.2
       52   14.15
       53   14.7
       69  <17.0

  2440484   16.8:
      500   16.0
      501   16.5:
      504   16.1:
      511   16.1:

  The authors (H. Busch & K. Haeussler) states that the cycle length is
about 370 days (probably concluded from other outburst observations not
listed in their table).

  from IAUC No. 4900  (Rosino)

  mag ~ 14.9 on 1989 Oct. 30 & 31.

--------------------------------------------------------------------------

  Since the start of systematic monitoring by amateur observers, three
outbursts have been known: 1994 Oct 25.889 mv=14.0, by Tonny Vanmunster,
1995 Aug. 21.979 (mv=14.1, Vanmunster), 1996 Dec. 7.88 (mag 14.3 by
J. Pietz).  The first two of them were immediately followed by several
observers, and were shown to fade quickly.  The exact location
of QY Per was first measured by N. James during the 1994 outburst:
03h 15m 36s.82 +42o 28' 13".8 (J2000.0).

Taichi Kato commented in [vsnet-obs 991]:

>    Judging from this information, it seems to me that the 1994 outburst
> is a normal (short) outburst rather than a superoutburst as suggested
> in CVC 54.  It is rather surprizing that this outburst may have surpassed
> the brightest recorded outburst, but still seems to be a normal (short)
> one.  A similar cases can be found in BZ UMa, DV UMa etc.  I have vague
> impression that some TOADs behave unlike many TOADs, in that they rarely
> show superoutbursts in spite of their very low outburst frequency
> (this is just the opposite how WZ Sge-type dwarf novae usually behave).
> Can someone comment on this?  Or are we only missing superoutbrusts?
> I would be eager to know what has been the case of the 1995 outburst of
> QY Per.

  The exact nature of QY Per is still unknown.  The present reported
magnitude being still above all previously recored outbursts, the present
outburst, if confirmed, can be a genuine superoutburst (first ever since
the discovery).

  We will undertake, when confirmed, an intensive observing campaign on
this object, as we have had (still ongoing) a very successful one in
DV UMa.  Please post timely to vsnet-alert confirmatory observations,
new findings, the progess of the outburst and observations.

Regards,
Taichi Kato and Makoto Uemura

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