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Thermophysical properties of Almahata Sitta meteorites (asteroid 2008 TC 3 ) for high‐fidelity entry modeling
Author(s) -
Loehle Stefan,
Jenniskens Peter,
Böhrk Hannah,
Bauer Thomas,
Elsäβer Henning,
Sears Derek W.,
Zolensky Michael E.,
Shaddad Muawia H.
Publication year - 2017
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/maps.12788
Subject(s) - asteroid , enstatite , meteorite , chondrite , emissivity , atmosphere (unit) , geology , atmospheric entry , mineralogy , materials science , astrobiology , thermodynamics , physics , optics , astronomy
Asteroid 2008 TC 3 was characterized in a unique manner prior to impacting Earth's atmosphere, making its October 7, 2008, impact a suitable field test for or validating the application of high‐fidelity re‐entry modeling to asteroid entry. The accurate modeling of the behavior of 2008 TC 3 during its entry in Earth's atmosphere requires detailed information about the thermophysical properties of the asteroid's meteoritic materials at temperatures ranging from room temperature up to the point of ablation ( T ~ 1400 K). Here, we present measurements of the thermophysical properties up to these temperatures (in a 1 atm. pressure of argon) for two samples of the Almahata Sitta meteorites from asteroid 2008 TC 3 : a thick flat‐faced ureilite suitably shaped for emissivity measurements and a thin flat‐faced EL 6 enstatite chondrite suitable for diffusivity measurements. Heat capacity was determined from the elemental composition and density from a 3‐D laser scan of the sample. We find that the thermal conductivity of the enstatite chondrite material decreases more gradually as a function of temperature than expected, while the emissivity of the ureilitic material decreases at a rate of 9.5 × 10 −5 K −1 above 770 K. The entry scenario is the result of the actual flight path being the boundary to the load the meteorite will be affected with when entering. An accurate heat load prediction depends on the thermophysical properties. Finally, based on these data, the breakup can be calculated accurately leading to a risk assessment for ground damage.