[Aavso-photometry] ALERT: KN Gem in outburst?

Tue Jan 25 21:47:09 EST 2005

This was reported to AAVSO today:

  KN GEM 0629+26  (UG:):
    JAN 25.4027  2453395.9027   14.6   JM    CCDV

If this is not a misidentification it would be a significant observation of
a long lost CV!

The only positive observation of KN Gem is the discovery observation
by Morgenroth on a single plate exposed on 24 January 1936KN Gem, at
photographic magnitude 13.0.

I have a chart based on the Henden Sumner sequence here:
http://joevp.20m.com/cgi-bin/i/charts/henden/And%20to%20Gem/Gem_KN_C_standard.gif

Bruce Sumner's sequence follows:

354  KN GEMINORUM   (UG)   Range: 13.0-<15.5p
     Position:   06 35 51.55  +26 52 58.0   (J2000, DWS)
     Magnitude:

ID     RA  (2000)   DEC       X    Y   N    V      ERR     B-V    ERR   SRC

a) Comparison star sequence

1    06 36 17.5  +26 57 11   346  253  4  11.657  0.125   0.333  0.052
2    06 35 56.2  +26 52 51    62   -7  4  11.680  0.120   1.003  0.074
3    06 36 21.7  +26 54 15   403   77  4  11.981  0.088   1.190  0.066
4    06 36 20.2  +26 48 08   383 -290  4  12.328  0.049   0.920  0.033
5    06 35 51.5  +26 52 21    -2  -37  4  12.650  0.014   0.879  0.010
6    06 36 13.9  +26 53 36   298   38  4  12.884  0.015   0.513  0.010
7    06 35 44.4  +26 54 36   -96   98  4  12.988  0.017   0.525  0.010
8    06 35 59.5  +26 51 57   106  -61  4  13.412  0.017   0.122  0.010
9    06 36 23.2  +26 54 33   423   95  4  13.690  0.015   0.968  0.009
10   06 35 53.5  +26 52 03    26  -55  4  13.879  0.014   0.544  0.008
11   06 36 11.0  +26 51 12   259 -106  4  14.323  0.017   0.611  0.011
12   06 36 21.5  +26 51 48   401  -70  4  14.643  0.014   0.874  0.011
13   06 35 57.3  +26 50 50    77 -128  4  14.708  0.015   0.605  0.009
14   06 36 09.3  +26 52 39   236  -19  4  15.118  0.016   0.550  0.013
15   06 35 52.3  +26 53 49     9   51  4  15.446  0.014   0.609  0.006
16   06 35 53.9  +26 50 41    31 -137  4  15.603  0.017   0.489  0.012
17   06 35 59.7  +26 53 50   108   52  4  15.932  0.012   0.612  0.006
18   06 35 50.8  +26 50 01   -11 -177  4  16.198  0.016   0.587  0.021
19   06 36 19.0  +26 53 46   366   48  4  16.256  0.013   0.581  0.004
10   06 35 51.0  +26 52 50    -7   -8  4  16.500  0.017   0.726  0.012
21   06 35 49.1  +26 53 07   -33    9  4  17.081  0.000   0.652  0.014
22   06 35 50.2  +26 53 02   -19    4  4  18.094  0.019   0.757  0.112

b) Wide-colour extension for CCD calibration

     06 36 00.2  +26 54 09   115   71  4  14.638  0.019   0.276  0.010
     06 36 16.1  +26 59 51   328  413  1  15.415  0.003   1.497  0.007

Notes:

1. The four brightest stars of this sequence are saturated and their
magnitudes are approximate. However they do have reliable ASAS-3
magnitudes:

      Henden          ASAS-3
   ID  V      B-V       V
   1    11.657  0.333    11.51+/-0.04
   2    11.680  1.003    11.55+/00.03
   3    11.981  1.190    11.81+/-0.05
   4    12.328  0.920    12.34+/-0.07

2. There is another star in this field with a reliable ASAS-3 magnitude:

  06 36 08.3  +26 47 25  V=11.01+/-0.03

3 The only positive observation of KN Gem is the discovery observation
by Morgenroth on a single plate exposed on 24 January 1936KN Gem, at
photographic magnitude 13.0. There is therefore no quiescence magnitude.
However Henden's photometry indicates no varying blue candidate in the
immediate vicinity of Morgenroth's position down to magnitude 19. Thus
if this variable exists, and is a dwarf nova, it must have a vary large
amplitude.

4. There is a bright Mira variable in this field, BR Gem, with which
KN Gem has been misidentified in the past (see IAUC 5083, 23 May 2001).
This variable was observed during the photometric determination as
follows:

 06 36 19.9  +26 52 54   378   -4  4  13.995  1.216   1.354  0.074

BR Gem has a range of 10.5-<15.5p and a period of 156 days. This sequence
is also suitable for this variable.

Bruce Sumner
17 February 2004

Mike Simonsen

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