1306.5010 (Ignacio Ferrin)

The Location of Oort Cloud Comets C/2011 L4 Panstarrs and C/2012 S1 ISON, on a Comets' Evolutionary Diagram    [PDF]

Ignacio Ferrin

(1) We reduced 9615 photometric observations of comets C/2011 L4 Panstarrs, C/2012 S1 ISON, C/1973 E1 Kohoutek, C/2002 O4 Honig and 1P/Halley, and we present their secular light curves (SLCs). (2) We measured the Slowdown Event (SDE) of C/2011 L4 Panstarrs, R(SDE)= -4.97+-0.03 AU (or t(SDE)=20120414+-3 d). (4) We measured the SDE of C/2012 S1 ISON, R(SDE)=-5.07+-0.03 AU (or 20130117+-3 d). Notice the coincidence with C/2011 L4 Panstarrs. For the absolute magnitude we find m(-1,1)= +12.7+-0.1, an intrinsically faint comet. (5) Technically speaking, since January 17th+-3 d, 2013, comet ISON has been on a stanstill for more than ~132 d, within the same magnitude +-0.2 mag, a rather puzzling feat (Figure 8). Since the nucleus brightens like R+2, the comet is actually dimming. There is a significant probability that the comet may turn off as comet C/2002 Honig did, or alternatively, it may desintegrate at perihelion. (6) Comet ISON is depleted in water content by a factor of 9.2, aproximatelly. (7) We locate the two comets in an evolutionary diagram. The diagram is forgiving, and the results are robust. (8) We present the SLC of comet C/1973 E1 Kohoutek, the famous comet that fizzled, and show reasons to conclude that it did not. We show the SLC of comet C/2002 O4 Honig, a comet that desintegrated. (10) We define the Jupiter Family Interval of Comets, as 1.24View original: http://arxiv.org/abs/1306.5010