TNO's, Pluto and satellites stellar occultations: 2014 and 2015


The predictions in this section are based on star catalogs produced by the Rio de Janeiro group, with star positions measured against the UCAC4 catalog.

The Pluto barycentric offset (with respect to the Horizons JPL ephemerides DE413) are based on positive stellar occultations observed between 2005 and 2013. More precisely, a linear fit to the observed offsets has been used to calculate the predicted offsets at epoch for each event in 2014 and 2015.

THE FORMULA USED FOR THE CALCULATION OF THE OFFSET IS GIVEN IN THE ASCII TABLES AVAILABLE IN EACH PAGE.
(NB. The offsets are written in the upper right corner on charts).

The following diameters have been adopted for drawing the shadow paths:

body diameter (km)
Pluto 2350 (solid body), 3114 (1% atmospheric drop)
Charon 1207
Nix 90
Hydra 110
P4 25

Pluto and satellites offsets are given with respect to the DE413 barycentric ephemeris, while the solution by Marc Buie is used for the satellites. Note that the P4 ephemeris is still UNCERTAIN.

Note that the magnitudes given in the lower line are R* and K* (and not V* and R*, as usual), so that it is possible to point out very red stars that are unreachable in visible bands, but observable in J, H or K.

NB. a K magnitude close to 50 means that the star is not in the 2mass catalog, usually because it is too faint.

!!Note also that those magnitudes, with a star symbol "*", are normalized to a common shadow velocity of 20 km/sec !!!
We are using for that the following formula:

Magnitude* = Magnitude_actual + 2.5*log10[velocity/20 (km/sec)]

This is intended to point out very slow events, for which a longer integration time is possible.

Bruno Sicardy and the Rio group

Independent predictions are given on the following links:

IOTA European Section page
Leslie's Young page
MIT page

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