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The Pluto stellar occultation of 14 June 2007
(visible from Southern Africa and Southern America).
Update: 04 June 2007



What will happen?

On 14 June 2007 between ~ 01:20 UT and ~01:30 UT, Pluto may occult a star, as seen from southern Africa and Southern America.

Coordinates of star, from Rio de Janeiro group:
r.a.= 17h 50mn 20.7392 sec
dec.= -16d 22' 42.210" (ICRF J2000)

Coordinates of star, from Geneva (Raoul Behrend):
r.a.= 17h 50mn 20.7441 sec
dec.= -16d 22' 42.208" (ICRF J2000)

The corresponding shadow maps are shown below:

Click on images for enhancement
click click
NB. Black lines: Pluto half-light shadow, dotted lines: Pluto 1% drop shadow (barely detectable)
dots plotted every mn, shadows move from right to left.

An offset of Pluto's system of -50 mas in right ascension (toward celestial west) and +50 mas (toward celestial north) has been applied to Pluto's DE413 ephemeris. This offset has been observed during the stellar occultation of 18 March 2007, and again during the 12 May 2007 event.
!!! ** IF THIS OFFSET IS MAINTAINED ON 14 JUNE 2007, THEN WE OBTAIN THE MAPS ABOVE.. ** !!!
However, this offset is not currently understood, so that it may be hazardous to apply at face value for the 14 June 2007 event!!!

The stellar tracks corresponding to the predictions shown in the upper left panel are shown below:

Click on image for enhancement
click
NB. The star is moving from right to left;
Each chord lasts for 5 mn. Note that the starting and stop times for the chords ARE DIFFERENT for

La Reunion (black): 01:20:30 ---> 01:25:30,
Africa (green): 01:22:30 ---> 01:27:30,
Brazil (blue) : 01:27:00 ---> 01:32:00, and
Chile (red): 01:28:00 ---> 01:33:00,
TAKE THIS INTO ACCOUNT WHEN PLANNING YOUR OBSERVATION!!!

Star magnitudes, see Vizier service:

Star magnitudes: B= 17.1 V= 15.7 R= 15.3 I= 14.0 J= 12.6 H= 11.7 K= 11.6
Pluto/Charon: B= 15.2 V= 14.4 I= 13.6 J= 13.0 H=12.9 K= 13.0

Thus, the star is about 1 magn **fainter** than Pluto in the red, about 0.5 magn **fainter** than Pluto in I band, and almost 2.5 magn **brighter** than Pluto in near IR.

Charts from 1.2m-swiss telescope, La Silla (Rg band), provided by Raoul Behrend
North is up, East is left. Field of view is 1.5x1.5 arcmin
click

Chart from Aladin DSS2 660 nm
North is up, East is left. Field of view is 8.9x8.9 arcmin
click

Post-event calculation of the actual shadow track, based on the occutation observed at Pico dos Dias. Pluto's offset amounts to -97 mas in r.a. and +77 mas in dec:

Click on images for enhancement
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See here Pluton moving from right to left during the 14 June 2007 occultation at Paranal. Images are from the Ultracam camera at the UT1 "Melipal" Very large Telescope (i' filter, centered around 750 nm).

click on image to start movie

For contacts, more information and/or comments, you can contact me me email at:

bruno.sicardy@obspm.fr

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