<u>Afekan Crater, Titan: Estimation of Impact Conditions.</u>

Details <u>Afekan Crater, Titan: Estimation of Impact Conditions.</u> <u>Afekan Crater, Titan: Estimation of Impact Conditions.</u>

Dec 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufm.p43c1688e&link_type=abstract

American Geophysical Union, Fall Meeting 2011, abstract #P43C-1688

Other

[5420] Planetary Sciences: Solid Surface Planets / Impact Phenomena, Cratering

Scientific paper

Introduction: Titan has very few impact craters. With more than 30% of the surface now imaged by Cassini Radar through data take T44 there are only seven certain impact structures known. The certain craters have two distinct morphologies, and the probable craters appear to mostly be more degraded version of these two types [1]. In relation to Afekan crater, with a diameter of~115 km, its ejecta blanket is largely covered by surrounding surface materials, its rim is extensively cut by chutes, and the broad flat floor carries a small central peak [1]. In this work are estimated the possible impact conditions, that could have given origin to this crater [2]. The models used here, are based on: some equations postulated by Holsapple (crater depth) [4]; scaling; polynomial analysis; and adaptation of quantum formalism for the mathematical representation of the energy pulse generated in the impact point, in where besides, is used one solution (soliton type) of the Korteweg-De Vries's equation [3]. The development of this crater is realized in 4 stages [5], in which are specified the variables of impact more common [5], as follows: a). Contact/Compression Stage: Diameter of impactor~28.6 km, velocity of impact~6.2 km/s,i.e., between 3 km/s and 15 km/s according [6], impact angle~82.8°, density of impactor~1.1 gm/cm3, volume of melt~1,449.4 km3, total energy of impact~1.6×1030 Erg, pressure to 1 km of the impact point~11,974.4 Gpa, the seismic shock-wave magnitude is>10.0 according the Richter Scale. b). Modification/Excavation Stage: Diameter of transient crater~76.6 km, number of ejected fragments~4.4×1010, the average size of fragments~11.9 m, average density of fragments~1.5 gm/cm3, distance of ejection of fragments~245.7 km, velocity of ejection~902.6 m/s, minimal angle of ejection~12.1°, maximum height of ejection~13.1 km. c). Collapse/Modification Stage: In this stage the pressure toward the final crater rim decrease to~3.6 Gpa. d). Final Crater Stage: The relation between the transient crater and the final crater is~0.67 [5], the time of creation for the final crater can be found in the interval [1.2 minutes,4.8 minutes], the hydrothermal zone could spread from~5.1 km to~38.3 km from the nucleus of impact,i.e., a hydrothermal band of~33.2 km, the lifetimes estimated for this hydrothermal band are of~4.3 Ma to~6.7 Ma with uncertainties of~(+/-) 0.9 % to~(+/-) 2.6 %,i.e., from~(+/-) 0.04 Ma to~(+/-) 0.17 Ma, hydrothermal temperatures from 0.25 years to 1,400 years after of the impact are estimated in~340 °C to~133.5 °C, the final temperature to the 6.7 Ma after of the impact is calculated in~10.2 °C + environment temperature.