Astronomy and Astrophysics – Astronomy
Scientific paper
Sep 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008dps....40.0207k&link_type=abstract
American Astronomical Society, DPS meeting #40, #2.07; Bulletin of the American Astronomical Society, Vol. 40, p.388
Astronomy and Astrophysics
Astronomy
Scientific paper
The crater produced by the impact of the Deep Impact projectile on Comet 9P/Tempel 1 was not visible from the spacecraft due to ejection of optically thick dust. However, the crater size can be estimated from the total mass of the ejecta cloud of 107 - 108 kg as seen by remote observers. Assuming that all of the mass in the crater left the comet, the corresponding cratering efficiency (mass of the material in the crater divided by impactor mass) is 2.5 x 104 - 2.5 x 105, or 1 - 2 orders of magnitude higher than expected for the impact velocity of Deep Impact (10.2 km/s) from impact experiments into porous ice/dust mixtures (e.g. Koschny and Grün, Icarus 154, 391, 2001; Holsapple, Icarus 191, 586, 2007). Only impacts into materials of extremely low strength (< 100 Pa) and of low porousity can create such large crater ejecta masses. Since comets are expected to be more porous and of somewhat higher strength (at the spatial scale of the impact), we investigate alternative possibilities to explain the large amount of observed dust and gas. All the material was created in less than an hour after the impact; therefore the sublimation from the freshly created surface (impact crater) is negligible for the total mass. However, due to the low thermal inertia of the cometary surface layer, the impact suddenly exposed extremely cold material to the surface of the nucleus. We will discuss possible mechanisms of prompting a small cometary outburst immediately after the impact, caused by solar heating of that freshly exposed material.
No associations
LandOfFree
Why is the Deep Impact crater on Comet Tempel 1 so large? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Why is the Deep Impact crater on Comet Tempel 1 so large?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Why is the Deep Impact crater on Comet Tempel 1 so large? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1436330