Daisaku Nogami
According to the report (vsnet-obs 2211) of J. Mc Kenna (AAVSO), the old nova GK Per may be undergoing one of its minor outbursts since its last one in 1992 July. This old nova (and also known as an intermediate polar) recently shows these presumably dwarf nova-type outbursts every about 3 years. The present outburst (if confirmed) may provide an opportunity in probing this "excellent laboratory of magnetic accretion".
1996 Feb. 26.054 UT mv=12.4 J. Mc Kenna
Some selected litertures:
* on short-term oscillations (QPOs, intermediate polar):
J. Patterson 1991, PASP 103, 1149 (optical)
M. Ishida et al. 1992, MNRAS 254, 647 (X-ray)
* on minor brightenings:
A. Bianchini et al. 1986, A&A 160, 367 (analysis of light curve)
S. -W. Kim et al. 1992, ApJ 384, 269 (dwarf nova-type model)
We would like to be providing updated information of this phenomenon through the VSNET home page (http://www.kusastro.kyoto-u.ac.jp/vsnet).
Regards,
Taichi Kato (VSNET sub-manager)
P. Schmeer reports further observations.
Visual magnitude estimates by P. Schmeer, Bischmisheim, Germany: GK PERSEI (NA+UGSS) Jan. 21.949 UT, 12.9 ; 30.890, 13.0:; 31.820, 13.0 ; Feb. 1.850 UT, 13.0:; 5.812, 12.9 ; 23.828, 12.9 ; 25.819, 12.7 Sequence: AAVSO Instrument: 203-mm SCT Fluctuation or start of a minor outburst?
These observations have been confirmed by visual observations (IAUC 6325) and by CCD photometry by D. Nogami (Ouda Station).
TAUSU 960223.573 18.05 Oud ORIV1159 960224.395 13.82 Oud PERGK 960226.463 12.39 Oud Ouda Station: 60-cm refl. + CCD + Johnson V filter
Regards,
Daisaku Nogami
AAVSO NEWS FLASH
V-band image on Mar. 10 (Ouda Station)
V-band image on Mar. 20 (Ouda Station)
Folks,
The AAVSO webpage alert notice 211 (1 August 1995) with regard to GK Persei included a chart that has a sequence dating from 1929. Surely this is one in need of a check via photoelectric photometry! There appears to be no modern published photometry (other than differential) for stars in the field. Everyone can rest easily, since it appears that both the zero-point and scale are basically correct, at least for the seven stars I measured, which span much of the range of magnitudes covered by the (f)-scale AAVSO chart. The bright star "99" (BD+43 0743) appears only on the (e)-scale chart.
The results below are from single observations except for the three faintest stars, which got two nights. N.B. the large uncertainty for the mag. 14 star, which is probably due to instrumental noise rather than variability in the star.
\Brian
AAVSO Name RA (2000) Dec V b-y remarks
GK Persei 3 31 12.0 +43 54 16 12.940 0.700 (1)
91 HD 21588 3 30 51.5 +43 59 06 9.085 0.178 (2)
99 BD+43 0743 3 31 55.9 +44 02 45 9.667 0.760 (3)
108 GSC 2874-0934 3 31 47.7 +43 54 22 11.061 0.252
123 GSC 2874-1053 3 30 47.7 +43 52 50 12.164 0.497
126 GSC 2874-0734 3 30 53.4 +43 56 19 12.558 0.437
.009 .006
132 GSC 2874-0823 3 31 25.3 +43 55 26 13.180 0.606
.026 .033
142 GSC 2874-0657 3 31 09.9 +43 57 28 14.25 0.84
.07 .11
remarks:
(1) - = HD 21629 = GSC 2874-0922. observation on 1995 Sep 30.5 UT.
(2) - spec type A2
(3) - = GSC 2874-1540
(by courtesy of VSOLJ)
1981-1996 (VSOLJ)
wide-field chart
Skiff's sequence, VSNET chart format
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