Gaia-DR2 distance to the W3 Complex

However, its distance has been controversial with discrepancies by a factor of two. Kinematic distances are in the range 3.9-4.2kpc as compared to 1.9-2.3kpc from spectrophotometric and trigonometric parallaxes, reinforcing previous claims that this arm exhibits peculiar velocities.

We used the astrometric information of a sample of 31 OB stars from the star-forming W3Complex to identify another 37 W3 members and to derive its distance from their Gaia-DR2 parallaxes with improved accuracy. The Gaia-DR2 distance to the W3Complex, 2.14^+0.08^_-0.07_kpc, coincides with the previous stellar distances of ~2kpc. The Gaia-DR2 parallaxes tentatively show differential distances for different parts of the W3 Complex: W3 Main, located to the NE direction, is at 2.30^+0.19^_-0.16_kpc, the W3 Cluster (IC1795), in the central region of the complex, is at 2.17^+0.12^_-0.11_kpc, and W3(OH) is at 2.00^+0.29^_-0.23_kpc to the SW direction.