OBSERVING 9P/Tempel 1 THE TARGET OF DEEP IMPACT

Nicolas Biver 03 July 2005

TOPICS


Magnitude estimates of 9P and drawings	Sky Maps for 9P/Tempel 1	Deep Impact home page

Trajectory and impact visibility	Predictions for 4 July 2005	Radio observation results

Orbit and viewing conditions of impact

Current Earth time of impact is 4 July 2005 5:52:15+-17sec UTC

Trajectory of Deep Impact (red), Rosetta (purple) 9P/Tempel 1 (blue) and Earth (black). Dotted lines: below ecliptic materialized by the cyan grid (0.2/0.02 AU step)

( French version and higher resolution French version )

Earth as seen from 9P/Tempel 1 at the time of Deep Impact encounter: regions visible in the dark shaded part of the Earth can see the impact during night time hours (e.g. Polynesia, Hawaii in twilight, North-West America)

Based on a paper published in "L'Astronomie" vol. 119, 308-311 (Juin 2005)

Possible Brightness Outburst

Here is an estimate of the surge of brightness of comet 9P/Tempel 1 after the impact on 4.244 July 2005, hypotheses are:

(1) Dust follows the release of gas (i.e. dust column density stays proportionnal to gas one);

(2) Amount of material released corresponds to a hemispherical shape crater of diameter 138m, depth 30m: 240000 m3 => 120000 tons (50% dust + 50% ice)

(3) grain size distribution: 1um - 1cm, dN(r) # dr/r3 (lifetime 5s - 13h)

(4) "Nuclear magnitude": aperture 3"

(5) "Total magnitude": coma 2'

There is no "forecast" here for what will hapen later to the comet (e.g. new active zone, runaway increase of new active area (e.g. tanks to crystalization of amorphous water ice,...), partial break-up or.... Nothing significant!)