Abstract
The Ophiuchus molecular cloud complex has produced in Lynds 1688 the
richest known embedded cluster within ̃300 pc of the Sun.
Unfortunately, distance estimates to the Oph complex vary by
nearly ̃40\% (̃120-165 pc). Here I calculate a new independent
distance estimate of 135 \pm 8 pc to this
benchmark star-forming region based on Hipparcos trigonometric
parallaxes to stars illuminating reflection nebulosity in close
proximity to Lynds 1688. Combining this value with recent
distance estimates from reddening studies suggests a consensus
distance of 139 \pm 6 pc (4\% error), situating
it within ̃11 pc of the centroid of the ̃5 Myr old Upper Sco OB
subgroup of Sco OB2 (145 pc). The velocity vectors for Oph and
Upper Sco are statistically indistinguishable within ̃1 km
s$^-1$ in each vector component. Both Oph and Upper Sco have
negligible motion (<1 km s$^-1$) in the Galactic vertical
direction with respect to the Local Standard of Rest, which is
inconsistent with the young stellar groups having formed via the
high velocity cloud impact scenario.
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