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> Comet ISON is in Outburst <

        Independent evidence is coming in to conclude that comet ISON is in outburst.   Firts the plots.  At the end, the images.

(1) On November 13th 06:35 UT, Emmanuel Jehin from the Trappist telescope in Chile reported that the water production rate had increased by a factor of x2 in 24 hours.   The value they were measuring was 2.0x10^28 molecules/s at 10.000 km.   They suspected that an outburst was going on.  We have plotted this value and additional observations in our water production rate plot and you can see the result in Figure 1.

Figure 1.  The new points from the Trappist telescope in Chile, NRAO and NACAY  indicate that comet ISON is experiencing a water outburst.  

(2) On November 13th, 06:51 UT Francois Kugel of the French group of observers, reported that they were seeing a magnitude increase of 1 magnitude in 24 hours.

(3) On November 14th, 01:42 UT, Nicolas Biver reports that comet ISON was visible to the naked eye.  He measured magnitudes 8.1 on Nov. 12.2, 7.4 on Nov. 13.22, and 6.4 on Nov. 14.2.    We have collected more than a hundred new visual observations of this comet and plotted them in our visual secular light curve, and you can see the result in Figure 2.

Figure 2.  The latest observations show that comet ISON is experiencing an outburst. 

(4) To determine the exact time of initiation of the outburst, we have enlarged a section of the last plot in Figure 3.

Figure 3.  From this plot it is possible to measure the initiation time of the outburst.  Notice also that observations seem to indicate that the outburst is decaying in intensity, although a few data points contradict this conclusion.  

The outburst began at -0.653+-0.004 AU from the Sun pre-perihelion, practically identically to the disintegration distance of comet Bressi.   This value corresponds to 2013 November 14.05+-0.15 d.

(5) A stunning set of 4 images by Juanjo Gonzalez shows the outburst in the fourth image.  The images were taken on November 3, 9, 12th and 14th.  


Figure 4.  This stunning set of four images by Juanjo Gonzalez shows a clear change in the brightness of the coma in the last image. 

An image taken by Mike Holloway from Holloway Comet Observatory, Van Buren, Ar, on November 13th, 2013 is compared with an image taken on November 14th.    The difference is striking.

Figure 5.  A comparison of two images taken by Mike Holloway on Nov. 13th and 14th, show the outburst clearly.

A possible interpretation of these plots is that fragmentation has begun, and the larger exposed area is producing the outburst.  However we still lack visual evidence to confirm if the nucleus is intact or has begun its fragmentation. 

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You can reach me at the University of Antioquia, Faculty of Exact
and Natural Sciences, Institute of Physics, Medellin, Colombia 0500-1000.
You can write to me at ferrin@fisica.udea.edu.co
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