Summary: Gaia will perform its observations from a quasi-periodic Lissajous-type orbit around L2, the second Lagrange point of the Sun/Earth--Moon system. The satellite will therefore (1) be in continuous motion w.r.t. the Solar system barycenter, and (2) be subject to/embedded in a continuously varying gravitational potential. As a result, the clock on board the satellite, which provides the time standard for the centroiding measurements, will experience a time-variable amount of special relativistic kinematic and general relativistic gravitational time dilation. This technical note addresses these issues, and indicates that allowance for both effects must be made. A detailed analysis of Gaia's clock accuracy and stability requirements is presented in GAIA-JdB-004.

Bibtex entry for this abstract:

   author = {J.~{de~Bruijne}},
   title={{R}elativistic time dilation at {L}2},
   type={Technical Note}