The Yarkovsky Effect in the Motion of NEAs . ... In this paper we evaluate the Yarkovsky effect on the motion of NEAs under the assumption that this acceleration depends on heliocentric distance as 1/r 2 and is characterized by the transverse component 2 in the orbital coordinate system. ... In some instances the Yarkovsky effect can be estimated by using only optical observations. Accounting for the Yarkovsky effect permits to include more optical observations in the orbit fitting process. ...