TY - JOUR
T1 - Processing of refractory meteorite inclusions (CAIs) in parent-body atmospheres
AU - Podolak, Morris
AU - Bunch, T. E.
AU - Cassen, Pat
AU - Reynolds, Ray T.
AU - Chang, S.
N1 - Funding Information:
We thank Drs. John Lewis and John Wood whose comments as (non)anonymous referees substantially improved this manuscript. We also thank Dr. Jack Lis-saner for many helpful discussions. This work was supported by the National Aeronautics and Space Administration Planetary Geosciences, Planetary Mate° rials and Geochemistry, and Life Sciences Exobiology Programs.
PY - 1990/3
Y1 - 1990/3
N2 - The refractory meteorite inclusions known as CAIs (calcium-aluminum rich inclusions) display melted rims that were produced by thermal events of only a few seconds duration. We show that gas dynamic deceleration in a temporary atmosphere around an accreting parent body, produced by gas release during accretion, could provide a regime of sufficiently high gas density and small scale height to achieve partial melting of the CAIs. In addition, the presence of dust in the atmosphere would increase the gradient of pressure with height (i.e., effectively reduce the scale height), lower the rate of blowoff (thus keeping more gas around the body), as well as allow dust particles to become trapped in the partially melted material as is observed in some cases. Thus, CAIs may be regarded as probes of a primitive atmosphere by virtue of the thermal and mineralogical alteration that occurred upon their passage through the atmosphere.
AB - The refractory meteorite inclusions known as CAIs (calcium-aluminum rich inclusions) display melted rims that were produced by thermal events of only a few seconds duration. We show that gas dynamic deceleration in a temporary atmosphere around an accreting parent body, produced by gas release during accretion, could provide a regime of sufficiently high gas density and small scale height to achieve partial melting of the CAIs. In addition, the presence of dust in the atmosphere would increase the gradient of pressure with height (i.e., effectively reduce the scale height), lower the rate of blowoff (thus keeping more gas around the body), as well as allow dust particles to become trapped in the partially melted material as is observed in some cases. Thus, CAIs may be regarded as probes of a primitive atmosphere by virtue of the thermal and mineralogical alteration that occurred upon their passage through the atmosphere.
UR - https://www.scopus.com/pages/publications/0025405642
U2 - 10.1016/0019-1035(90)90169-A
DO - 10.1016/0019-1035(90)90169-A
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AN - SCOPUS:0025405642
SN - 0019-1035
VL - 84
SP - 254
EP - 260
JO - Icarus
JF - Icarus
IS - 1
ER -