We fit the data for the binary-lens microlensing event MACHO 98-SMC-1 from 5 different microlensing collaborations and find two distinct solutions characterized by binary separation d and mass ratio q : ( d,q ) = ( 0.54 , 0.50 ) and ( d,q ) = ( 3.65 , 0.36 ) , where d is in units of the Einstein radius .
However , the relative proper motion of the lens is very similar in the two solutions , 1.30 { km } { s } ^ { -1 } { kpc } ^ { -1 } and 1.48 { km } { s } ^ { -1 } { kpc } ^ { -1 } , thus confirming that the lens is in the Small Magellanic Cloud .
The close binary can be either rotating or approximately static but the wide binary must be rotating at close its maximum allowed rate to be consistent with all the data .
We measure limb-darkening coefficients for five bands ranging from I to V .
As expected , these progressively decrease with rising wavelength .
This is the first measurement of limb darkening for a metal-poor A star .