[vsnet-alert 2236] More on PU Per

[Taichi Kato <tkato>]

More on PU Per

On the 1995 October outburst and historical data:

(from vsnet-obs 1338,
  http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/obs01000/msg00338.html)

  PU Per has faded quite rapidly as the following observations indicates.

  mid-UT     V-C   S.D.   N band    V-mag
---------------------------------   -----
951013.714  3.110 0.099  67 V        16.5
951014.624  4.966 0.283   4 V        18.4

  comparison star: 02h41m58s.80 +35o44'13".4 (J2000.0)
                   GSC V=13.5 (13.42 in revised VSNET chart)

  From low-amplitude hump-like features (likely orbital humps during
decline) in Oct. 13 observations, we have estimated a rough period of
0.058 +/- 0.002 day.  If this modulation actually reflects the orbital
motion, this dwarf nova is suspected to be a ultrashort orbital period
SU UMa-type dwarf nova (WZ Sge-like object or extreme TOAD).  The rate
of decline supports this idea.  The second outburst observed in Romano,
Minello (1976, IBVS 1140) can be identified as a superoutburst.

  Historical outbursts by Romano, Minello (1976):

    I max            II max
2440641  [19.1   2441280  [19.0
    644   17.4       295   15.2
    645  [19.0       298   15.2
                     301   16.6
                     303   19.0
                     308  [19.0

  Further close monitoring would be recommended.  One should remember
the present short outburst may trigger a superoutburst as recently
observed in GO Com.  Please continue a close watch.

Regards,
Taichi Kato, Daisaku Nogami & Ouda team

Outburst astrometry:

(from vsnet-obs 1340,
  http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/obs01000/msg00340.html)

   Makoto Iida (VSOLJ) has kindly measured the position of PU Per from
a CCD image taken at Ouda Station.

            R.A. (J2000.0)  Decl.
--------------------------------------------------------------
  PU Per 02h42m16s.14   +35o40'46".4   (present outburst)
         02 42 16       +35 40 29      Downes & Shara (1993)

  reference: 10 GSC stars, mean residual 0".1

More on historical behavior:

(from vsnet-obs 1460,
  http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/obs01000/msg00460.html)

   We have found one more literature on PU Per and PV Per (Busch, H.,
H\"aussler, K., 1979, VSS 9, 125).   Following outbursts were observed
from Sonneberg plate collection.  My comments are added based on recent
classification of these stars as probable SU UMa-type dwarf novae.

PU Per
------

    JD        mag     comment
 2439051.34  [16.0
    9052.36   15.5   superoutburst
    9053.44   16.0
    9056.48   16.0

    9380.56   16.0
    9385.52   14.7   superoutburst lasting at least 10 days
    9386.53   14.7
    9388.49   15.0
    9390.61   15.5

 2441300.23
      - .49   15.6-15.7 (five plates) = identical with the second outburst
    1304.38  [16.0                      by Romano, Minello (1976)
                                        = superoutburst

  From these data, one may conclude:

  1) The shortest recorded interval between superoutbursts is ~330 day.
  2) Normal outbursts seem to be rare.  Some may be missed due to their
     faintness, though.

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