[vsnet-alert 4354] (fwd) Intermediate state of BZ Cam

[Daisaku Nogami <daisaku@uni-sw.gwdg.de>]

 From: "Ivan L. Andronov" <il-a@mail.ru>
 Subject: Intermediate state of BZ Cam
 Date: Tue, 7 Mar 2000 17:07:50 +0200

Intermediate state of BZ Cam

I.L.Andronov (1,2), K.Gazeas (2), P.G.Niarchos (2)
1 Department of Astronomy, Odessa State University, Ukraine
2 Department of Astrophysics, Astronomy and Mechanics,
  Athens University, Greece


The star BZ Cam = 0623+71 was recently reported to be decreasing
in brightness by T. Watanabe ([vsnet 1965] BZ Cam preprint),
who observed the star declining from 12.3 (JD 24 51061.269)
to 13.9 (JD 51551.125). The characteristic time for this interval
is dt/dm=294+-7 days/mag.
   We have observed the star in V filter with the 40-cm telescope
of the Athens University observatory by using the ST-8 CCD camera
on March 6/7, 2000 (JD 24 51610.375-.491) during 3.5 hours. The
comparison star "4" was used (Henden and Honeycutt, 1996) with
V=12.868.
   BZ Cam varied from 12.9 to 13.2, far either from the last value
13.9 observed by T.Watanabe or from the value 14.13+-0.03 expected
from continuation of the linear decline.
   Thus we conclude that the star is bright again, with an incline
much faster (<60 days) than the decline from the same magnitude
(~250 days assuming linear decrease).
   The previous observations of this star in 1991 have shown
the power law shape of the periodogram for fast variability:
S(f) ~ f^{-g} with a power index g=1.08+-.05 in U and 0.86+-0.04
in R (Shakhovskoy et al., 1992a) or 1.51+-0.13 (Patterson et al.,
1996). It is interesting to check, whether this parameter is
dependent on the mean brightness, as, e.g. in AM Her
(Shakhovskoy et al., 1992b). More details on the "red noise"
in cataclysmic variables may be found in Andronov (1999ab),
see also http://ila.webjump.com


References
Andronov I.L.: 1999a, "Red noise" from the accreting magnetic
  white dwarfs. - Astron. Soc. Pacif. Conf. Ser., v 169., 326-336.
Andronov I.L.: 1999b, "Wavelet analysis of the irregularly spaced
  time series".- in: "Self-Similar Systems", eds. V.B. Priezzhev,
  V.P. Spiridonov, Dubna, Russia, JINR, 1999, 57-70.,
  httm://ila.webjump.com
Henden A.A., Honeycutt R.K: 1996, "Secondary photometric standards
  for northern nova-like cataclysmic variables", PASP, 107, 324-346.
Patterson J., Patino R., Thorstensen J.R., Harvey D., Skillman D.R.,
  Ringwald F.A.: 1996, "Periods and quasiperiods in the cataclysmic
  variable BZ Camelopardalis", AJ 111, 6, 2422-2430.
Shakhovskoy N.M., Efimov Yu.S., Andronov I.L., Kolesnikov S.V.:
  1992, BZ Camelopardalis = 0623+71 : The Cataclysmic Variable
  inside a Bow-Shock Nebula.- in: "Planetary Nebulae. Abstracts",
  Innsbruck, 1992, p.80; IAUSymp. 155, Kluwer, 1993, 407.
Shakhovskoy N.M., Kolesnikov S.V., Andronov I.L. : 1992b,
  "AM Herculis at the low state: The circular polarization
  disappeared", in: 'Magnetism in Stars', Moscow, Nauka Publ.,
  p. 148-154.

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp