Pluto Occultation March 18, 2007

On March 18th, 2007, Pluto will occult P445.3 (= 2UCAC 25823784; as originally published in McDonald, 2000; Table). The following prediction results from the analysis of 38 strip scans obtained at the Lowell Observatory Astrograph by MIT observers during 2005-2007. These are compared with an offset to the light-time corrected, geocentric JPL Horizon's ephemeris (System DE413 - Pluto source file; PLU013; Earth center source file; DE405) determined by comparing the Pluto system barycenter to the measured barycenter from the strips. Proper motion has been applied up to the time of the occultation (RA: -10.8 ± 8.0 mas/yr, Dec: -21.4 ± 7.9 mas/yr). The offsets between the measured RA and Dec of P445.3 and its UCAC2 values at the time of the event are also given in the table.

Reference star position: (UCAC2, at epoch of event)	RA (h:m:s; J2000)	Dec (d:m:s; J2000)	UCAC Mag¹
P445.3	17 55 05.6914	–16 28 34.465	15.3
Corrected P445.3	17 55 06.6935	–16 28 34.355
¹The UCAC bandpass (579-642nm) is between V and R
Offsets from Reference Position/Ephemeris²
Body	RA (arcsec)	Dec (arcsec)	Notes
P445.3	+0.030± 0.017	+0.12± 0.017	From 26 strip scans
Pluto System Barycenter	-0.093± 0.024	0.073± 0.023	From 6 strip scans
Pluto	-0.095± 0.024	0.075± 0.023	From 6 strip scans
²All "offsets" are defined in the ("corrected" - "reference") or ("observed" - "catalog") sense. IE offsets should be added to reference positions.

Shadow Path
The lines across the globe pictured below demonstrate our predicted Pluto path. The shaded area represents night time and the unshaded area represents where it will be day at the time of the occultation.
	P445.3 Prediction (as of: 2007 03 01)
Geocentric Mid-time (yyyy month dd hh:mm:ss)	2007 March 18 10:58:15 UT
Minimum Geocentric Separation (arcsec)	0.274± 0.029
Position Angle (deg; Pluto relative to the star)	-15.99
Geocentric Velocity (km/s)	7.0
Prediction Version	P445.3-AST-1.4

Prediction Notes

The separation between the center line and each of the limb lines is an estimated Pluto radius of 1400 km for a flux drop of 6% for a partial occultation by the atmosphere.
Independent predictions for this event are given on the websites of Leslie Young (map given here) and Bruno Sicardy

Archive of all P445.3 occultation predictions based on alternate sources of data, including past predictions

P445.3 Occultation Predictions for Individual Sites

Site	East Longitude	Latitude	Distance (km)	Pluto Immersion (UT)	Mid-Time (UT)	Pluto Emersion (UT)
Magdalena Ridge Obs.	–107 11 05	33 58 36	1102	10:51:55	10:54:02	10:56:10
Mt. Graham	–111 39 54	35 12 12	1010	10:51:02	10:53:25	10:55:48
Mt. Hopkins	–111 53 04	31 41 19	1226	10:51:12	10:52:52	10:54:32
Geocentric	----------	---------	6400	----------	10:58:15	----------

Please direct all inquiries to Planetary Astronomy Lab (planetary-astronomy@mit.edu)

Last updated by Carlos A Zuluaga(czuluaga@mit.edu) 2007-03-06 04:10

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