TNO's, Pluto and satellites stellar occultations: 2013


The predictions in this section are based on star catalogs produced by the Rio de Janeiro group, with star positions measured against the UCAC2 catalog.

The TNO's offsets (with respect to the Horizons JPL ephemerides) were measured by the same group between 2007 and 2012.

NB. The offsets are written in the upper right corner on charts. Their calculations and the reference ephemerides used are given in the tables available in each page.

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

body diameter (km)
Pluto 2350
Charon 1208
Nix 100
Hydra 100
P4 20
2002TX300 286
Eris 2400
Orcus 946
Quaoar 844
Haumea 1150
Makemake 1500
Varuna 500
Ixion 650
Sedna 1600
2003AZ84 686

Note that in a few cases, the shadow track is too far away from Earth to be visible on the maps. The prediction has been maintained, however, in case the event be eventually visible once astrometric update is available. The distance of closest approach and position angle of the body wrt the star are written at the bottom of the map, and allow one to derive the actual the shadow path in those cases.

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

We have further applied a linear extrapolation of the offsets that we determined using Pluto and Charon occultations between 2005 and 2012.

For simplicity, we have used the linear extrapolation of this offset at a FIXED date: 30 June 2013. This offset has then been applied for all dates in 2013. This offset should be fine for prediction, but should be refined prior to each event.

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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