A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations

TL;DR

This paper reports a precise parallax measurement of the Orion Nebula Cluster using VLBA observations, indicating it is closer than previously thought, which impacts stellar luminosity and age estimates.

Contribution

The study provides a new, more accurate distance measurement to the Orion Nebula Cluster using VLBA, refining previous estimates and implications for stellar properties.

Findings

Distance to the Orion Nebula Cluster is 389 +24/-21 parsecs.

The cluster is closer than the previously accepted 480 parsecs.

Stellar luminosities are reduced by a factor of ~1.5 based on the new distance.

Abstract

We determine the parallax and proper motion of the flaring, non-thermal radio star GMR A, a member of the Orion Nebula Cluster, using Very Long Baseline Array observations. Based on the parallax, we measure a distance of 389 +24/-21 parsecs to the source. Our measurement places the Orion Nebula Cluster considerably closer than the canonical distance of 480 +/- 80 parsecs determined by Genzel et al. (1981). A change of this magnitude in distance lowers the luminosities of the stars in the cluster by a factor of ~ 1.5. We briefly discuss two effects of this change--an increase in the age spread of the pre-main sequence stars and better agreement between the zero-age main-sequence and the temperatures and luminosities of massive stars.