Displacement of the Sun from the Galactic plane

Abstract

We have carried out a comparative statistical study for the displacement of the Sun from the Galactic plane (z⊙) following three different methods. The study has been carried out using a sample of 537 young open clusters (YOCs) with, lying within a heliocentric distance of 4 kpc, and 2030 OB stars observed up to a distance of 1200 pc, all of which have distance information. We statistically separated the members of the Gould Belt before investigating the variation in the z⊙ estimation with different upper cut-off limits in the heliocentric distance and distance perpendicular to the Galactic plane. We have found that z⊙ varies in the range ∼13-20 pc from the analysis of YOCs and in the range ∼6-28 pc from the analysis of OB stars. A significant scatter in z⊙, because of different cut-off values, is noticed for the OB stars, although no such deviation is seen for the YOCs. We have also determined scaleheights of 56.9+3.8-3.4 and 61.4+2.7-2.4 pc for the distribution of YOCs and OB stars, respectively. © 2007 RAS.