Ferdinando, la tabella indicata in

http://newton.dm.unipi.it/cgi-bin/neodys/neoibo?objects:Apophis;risk

manca di una legenda. la probabilità di impatto attualmente stimata per il 2036 è p_RE?
2/100 000 circa?

(99942) Apophis - impactor table


Object: 99942

date MJD sigma sigimp dist +/- width stretch p_RE exp. en. PS
YYYY/MM (RE) (RE) RE/sig MT
------------------------------------------------------------------------------------------------
2036/04/13.371 64796.371 -2.470 0.000 1.15 +/- 0.003 3.32E+03 2.07E-05 8.26E-03 -2.57
2042/04/13.720 66987.720 -2.494 0.000 1.41 +/- 0.000 1.12E+06 5.26E-08 2.10E-05 -5.24
2044/04/13.296 67718.296 -2.434 0.000 2.08 +/- 0.000 6.27E+05 3.57E-08 1.42E-05 -5.44
2069/04/13.078 76849.078 2.112 0.000 0.97 +/- 0.000 3.74E+05 4.41E-07 1.76E-04 -4.56
2069/10/15.971 77034.971 1.466 0.000 0.48 +/- 0.160 1.52E+06 3.81E-07 1.52E-04 -4.63
2072/10/15.333 78130.333 -3.870 0.000 0.48 +/- 0.089 6.09E+06 1.57E-10 6.26E-08 -8.03
2076/07/30.873 79514.873 2.720 1.214 34.89 +/- 26.902 1.49E+07 3.73E-11 1.44E-08 -8.69


Based on 1000 optical observations (of which 5 are rejected as outliers)
from 2004/03/15.108 to 2006/08/16.627, and also on seven radar data points
on 2005/01/27, 2005/01/29, 2005/01/31, 2005/08/07 and 2006/05/06.

Coordinates are given on the Target Plane
Unit is one Earth radius, but impact cross section
has radius between 2.15 and 2.16 Earth radii

"Data speak for themselves" -Reverend Thomas Bayes 1702-1761
P(Ai|E)=(P(E|Ai)P(Ai))/P(E)