The Near Earth Asteroid Rendezvous-Shoemaker ( ‘ ‘ NEAR ’ ’ ) spacecraft orbited and ultimately landed on the near-Earth asteroid 433 Eros .
One of the primary science objectives of NEAR was the MAG experiment , which measured the magnetic field in the vicinity of Eros during orbit and after landing .
Eros is therefore at the present the best characterized asteroid using in situ measurement of magnetism .
MAG results suggested that Eros was very unmagnetized—with an upper bound on the natural remanent magnetism ( NRM ) placed at 1.9 \times 10 ^ { -6 } \mathrm { A \cdot m ^ { 2 } \cdot kg ^ { -1 } } —especially when compared to meteorite samples of analogous composition .
Since meteorites and asteroids are typically believed to represent the remnants of disrupted parent bodies , the ramifications of the low level of magnetization of Eros are considerable , since it could imply disparate origins for objects of similar composition .
In this paper , we explore whether there are any systematic effects related to the actual process of measurement and derivation of the Erotian NRM , and whether such effects played a role in the low levels of NRM derived for Eros .
By simulating the orbit of NEAR around Eros and using the field strength values measured by NEAR , we find that we are able to place a higher bound on the NRM of Eros by a factor of at least an order of magnitude higher than that originally suggested by Acuña , et al . ( 2002 ) .
We find that if we suppose Eros to be made up of constituents that have roughly uniform magnetization directionally , that it is possible to infer an L or LL chondrite-type composition for Eros within the bounds of values for remanent magnetism reported in the meteorite record .
The results provide a more rigorous confirmation of the suggestion by Wasilewski , et al . ( 2002 ) that Eros can not be ruled out as an L- or LL-type analogue .