VLBA Determination of the Distance to Nearby Star-forming Regions. VIII. The LkH$\alpha$ 101 cluster

TL;DR

This study uses VLBA radio observations to measure the distance to the LkHα 101 star-forming region, providing a precise estimate that clarifies previous uncertainties about its location.

Contribution

First direct parallax measurement of the LkHα 101 cluster using VLBA, resolving longstanding distance controversy.

Findings

Distance to LkHα 101 cluster is 535±29 pc.

Radio observations successfully detected a young star at multiple epochs.

Results clarify the cluster's position in the galaxy.

Abstract

The LkH$\alpha$ 101 cluster takes its name from its more massive member, the LkH$\alpha$ 101star, which is an $\sim15$ M$_\odot$ star whose true nature is still unknown. The distance to the LkH$\alpha$ 101 cluster has been controversial for the last few decades, with estimated values ranging from 160 to 800 pc. We have observed members and candidate members of the LkH$\alpha$ 101 cluster with signs of magnetic activity, using the Very Long Baseline Array, in order to measure their trigonometric parallax and, thus, obtain a direct measurement of their distances. A young star member, LkH$\alpha$ 101 VLA J043001.15+351724.6, was detected at four epochs as a single radio source. The best fit to its displacement on the plane of the sky yields a distance of 535$\pm$29 pc. We argue that this is the distance to the LkH$\alpha$ 101 cluster.