TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. II. CEP A AND NGC 7538

We report trigonometric parallaxes for the sources NGC 7538 and Cep A, corresponding to distances of 2.65+(0.12)(-0.11) and 0.70+(0.04)(-0.04) kpc, respectively. The distance to NGC 7538 is considerably smaller than its kinematic distance and places it in the Perseus spiral arm. The distance to Cep A is also smaller than its kinematic distance and places it in the "Local" arm or spur. Combining the distance and proper motions with observed radial velocities gives the location and full space motion of the star-forming regions. We find significant deviations from circular galactic orbits for these sources: both sources show large peculiar motions (greater than 10 km s(-1)) counter to galactic rotation and NGC 7538 has a comparable peculiar motion toward the Galactic center.