V651 Mon, the binary central star of NGC 2346 currently showing a deep eclipsing episode second time in the history, seems to entering a new stage of the evolution of eclipses. Since Dec. 1, no available observations have shown this star below mag 14, in contrast to deep eclipses reported in November. The cloud in front of the binary getting transparent or homogeneous again?
YYMMDD(UT) mag code 961108.141 139: POY 961109.095 136 JEN 961109.735 <138 Wnt 961110.139 <131 POY 961113.667 12.29V Kis 961114.250 134 KIN 961114.610 130 Wnt 961114.823 12.47V Oud 961115.694 123 Wnt 961116.640 121 Wnt 961116.699 12.00V Oud 961119.747 12.41V Oud 961121.089 146: POY 961122.672 <136 Wnt 961129.715 <139 Wnt 961130.619 <135 Ths 961130.705 <139 Wnt 961201.812 136 Wnt 961202.062 131 POY 961202.822 131 Wnt 961203.747 127 Wnt 961204.000 120 KSL 961205.067 124 POY 961206.765 126 Wnt 961207.597 136 Wnt 961209.589 12.88 Oud 961211.607 12.58 Oud 961213.966 132 DIE 961214.660 12.88 Oud 961215.631 139 Ths 961219.331 130 SQN (compiled from vsnet-obs reports)
Despite intereference by the moon, observers are strongly urged to monitor this star for the coming week when the next 16-day-period eclipse is expected.
A CCD image taken on Dec. 9, when a deep eclipse was expected, clearly shows the star.
This message is to give you my opinion of what is going on with V651 Mon. I believe this second cloud is smaller and/or closer to the binary than the first one that caused the variations in 1984-1985, presumably due to occultations (a more appropriate word than eclipses, as suggested by R.H. Mendez in the 7th Latin-American Regional Meeting of the IAU in 1992) by a dust-reach cloud in front of the binary orbit. It apparently is passing one side of the orbit projected on the sky, and entering the other side, hence producing two occultations in two different phases. If so, the first minimum will decrease (as observed). and the second will increase and then also decrease in the months to come.
Hope this will encourage the fallow-up observations by VSNET enthusiastic members, whose work is impressively valuable and useful. I wish you and all those related to VSNET a Marry Christmas and a very fruitful 1997. I also hope to be able to join you all very soon in the fallow-up of this and other exciting objects.
Instituto de Astronomia, UNAM
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