The System of Molecular Clouds in the Gould Belt

TL;DR

This study redefines the spatial orientation and kinematic properties of the Gould Belt's molecular cloud system, revealing its inclined ellipsoidal shape and non-random past motion over 60 million years.

Contribution

It provides precise parameters of the Gould Belt's molecular cloud system and reconstructs its past trajectory using high-accuracy distance data and maser-based velocity measurements.

Findings

The system is an inclined ellipsoid with specific orientation parameters.

The clouds' past trajectory over 60 Myr was reconstructed.

Molecular complexes exhibit non-random motion patterns.

Abstract

Based on high-latitude molecular clouds with highly accurate distance estimates taken from the literature, we have redetermined the parameters of their spatial orientation. This system can be approximated by a 350x235x140 pc ellipsoid inclined by the angle i=17+/-2 degrees to the Galactic plane with the longitude of the ascending node l{\Omega}=337+/-1 degrees. Based on the radial velocities of the clouds, we have found their group velocity relative to the Sun to be (u0,v0,w0) = (10.6,18.2,6.8)+/-(0.9,1.7,1.5) km/s. The trajectory of the center of the molecular cloud system in the past in a time interval of ~60 Myr has been constructed. Using data on masers associated with low-mass protostars, we have calculated the space velocities of the molecular complexes in Orion, Taurus, Perseus, and Ophiuchus. Their motion in the past is shown to be not random.