Comparison of comet 81P/Wild 2 dust with interplanetary dust from comets.
The Stardust mission returned the first sample of a known outer solar system body, comet 81P/Wild 2, to Earth. The sample was expected to resemble chondritic porous interplanetary dust particles because many, and possibly all, such particles are derived from comets. Here, we report that the most abundant and most recognizable silicate materials in chondritic porous interplanetary dust particles appear to be absent from the returned sample, indicating that indigenous outer nebula material is probably rare in 81P/Wild 2. Instead, the sample resembles chondritic meteorites from the asteroid belt, composed mostly of inner solar nebula materials. This surprising finding emphasizes the petrogenetic continuum between comets and asteroids and elevates the astrophysical importance of stratospheric chondritic porous interplanetary dust particles as a precious source of the most cosmically primitive astromaterials.
Ishii
Hope A
HA
Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. hope.ishii@llnl.gov
Bradley
John P
JP
Dai
Zu Rong
ZR
Chi
Miaofang
M
Kearsley
Anton T
AT
Burchell
Mark J
MJ
Browning
Nigel D
ND
Molster
Frank
F