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The Yarkovsky Effect - Part 7 of 7

W.K. Hartmann et al. (1999) Reviewing the Yarkovsky effect: New
light on the delivery of stone and iron meteorites from the asteroid
belt (MAPS 34, 1999, A161-A167, excerpts + summary):

Possible Observable Consequences

Our basic result is that much stony debris in the 0.1 to 10 m size range
would be rapidly cleared from the belt and delivered to planets as
meteorites, whereas much iron debris in this size range would have much
less efficient delivery out of the belt and would acquire longer CRE
ages, as observed.
Small carbonaceous bodies are so weak that they are destroyed in Earth's
atmosphere, and Earth's surface thus does not get a representative
sample of carbonaceous meteorites, compared to the compositional average
of interplanetary material. This is proved by the fact that the primary
signature of meteoritic material in the lunar regolith is carbonaceous,
whereas carbonaceous material represents only about a few percent of the
falls on Earth.

Ejection of carbonaceous chondrites from the belt presents a special
problem:

It is dynamically difficult to deliver C- and P-class fragments - the
putative carbonaceous chondrites from beyond 2.6 AU. As resonances in
that region pump up eccentricities, the objects are lost to Jupiter
before they become Earth-crossing, as Wetherill and Chapman (1988) note.
Even Yarkovsky drift among small objects originating in that region
would send some objects outward to the 5:2 and 2:1 resonances at 2.82
and 3.28 AU, which would produce mostly scattering by Jupiter or Jovian
collisions. Also, the carbonaceous C-class bodies in the outer belt may
be so weak that collisions in the belt may erode their fragments faster
than they can be delivered to resonances.

Some references:

BOTTKE W.F., RUBINCAM D.P. and BURNS J.A. (1998) Consequences of the
Yarkovsky effect on the orbital evolution of meteorids: A prospectus
(abs. Lunar Planet. Sci. 29, Abstract # 1424, Lunar and Planetary
Institute, Houston, Texas, USA, CD-ROM).

FARINELLA P., MARZARI F., VOKROUHLICKY D., HARTMANN W.K., DAVIS D.R. and
WEIDENSCHILLING S.J. (1997) Meteorite delivery through Yarkovsky orbital
drift (Bull. Amer. Astron. Soc. 29, 1045).

FARINELLA P., VOKROUHLICKY D. and HARTMANN W.K. (1998) Meteorite
delivery via Yarkovsky orbital drift (Icarus 132, 378-387).

HARTMANN W.K. and RYAN E.V. (1996) Possible evidence of Yarkovsky
depletion of debris from the asteroid belt and effects on asteroid
surfaces (Bull. Amer. Astron. Soc. 28, 1103).

NEIMAN V.B., ROMANOV E.M. and CHERNOV V.M. (1965) Ivan Osipovich
Yarkovsky (in Russian, Earth and Universe 4, 63-64).

PETERSON C. (1976) A source mechanism for meteorites: Controlled by the
Yarkovsky effect (Icarus 29, 91 -111).

RUBINCAM D.P. (1988) Yarkovsky thermal drag on LAGEOS (J. Geophys. Res.
93, 13 805-13 810).

RUBINCAM D.P. (1998) Yarkovsky thermal drag on small asteroids and
Mars-Earth delivery (J. Geophys. Res. 103, 1725-1732).

VOKROUHLICKY D. (1998) Diurnal Yarkovsky effect as a source of the
mobility of meter-sized asteroidal fragments - 1. Linear theory (Astron.
Astrophys. 335, 1093-1100).

VOKROUHLICKY D. and FARINELLA P. (1998) Orbital evolution of asteroidal
fragments into the v6 resonance via Yarkovsky effects (Astron.
Astrophys. 335, 351-362).


Best wishes,

Bernd

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