The distances to star-clusters hosting Red Supergiants: $\chi$ Per, NGC 7419, and Westerlund 1

Abstract

Galactic, young massive star clusters are approximately coeval aggregates of stars, close enough to resolve the individual stars, massive enough to have produced large numbers of massive stars, and young enough for these stars to be in a pre-supernova state. As such these objects represent powerful natural laboratories in which to study the evolution of massive stars. To be used in this way, it is crucial that accurate and precise distances are known, since this affects both the inferred luminosities of the cluster members and the age estimate for the cluster itself. Here we present distance estimates for three star clusters rich in Red Supergiants ($\chi$ Per, NGC 7419 and Westerlund 1) based on their average astrometric parallaxes $\bar{\pi }$ in Gaia Data Release 2, where the measurement of $\bar{\pi }$ is obtained from a proper-motion screened sample of spectroscopically-confirmed cluster members. We determine distances of $d=2.25_{-0.14}^{+0.16}$kpc, $d=3.00_{-0.29}^{+0.35}$kpc, and $d=3.87_{-0.64}^{+0.95}$kpc for the three clusters respectively. We find that the dominant source of error is that in Gaia's zero-point parallax offset ${\pi }_{\mathrm{ZP}}$, and we argue that more precise distances cannot be determined without an improved characterization of this quantity.

5 pages, 9 figures, to appear in MNRAS

References in corpus (10)

• The Gaia mission
• The most massive stars in the Arches cluster
• Fitting the young main-sequence; distances, ages and age spreads
• Intermediate to low-mass stellar content of Westerlund 1
• The cool supergiant population of the massive young star cluster RSGC1
• The distance and neutral environment of the massive stellar cluster Westerlund 1
• The evolution of Red Supergiants to supernova in the LMC cluster NGC 2100
• Discrepancies in the ages of young star clusters; evidence for mergers?
• NGC 7419: A young open cluster with a number of very young intermediate mass pre-MS stars
• Multi-wavelength study of a young open cluster NGC 7419

Cited by in corpus (15)

• A new mass-loss rate prescription for red supergiants
• The `Red Supergiant Problem': the upper luminosity boundary of type-II supernova progenitors
• The IACOB project. VI. On the elusive detection of massive O-type stars close to the ZAMS
• A deep spectromorphological study of the $\gamma$-ray emission surrounding the young massive stellar cluster Westerlund 1
• The Age of Westerlund 1 Revisited
• Exploring the Mass Loss Histories of the Red Supergiants
• Unlocking Galactic Wolf-Rayet stars with $\text{Gaia}$ DR2 II: Cluster and Association membership
• Understanding the TeV $\gamma$-ray emission surrounding the young massive star cluster Westerlund 1
• The impact of realistic red supergiant mass-loss on stellar evolution
• Westerlund 1 under the light of Gaia EDR3: Distance, isolation, extent, and a hidden population
• Probing Red Supergiant dynamics through photo-center displacements measured by Gaia
• Distance and age of the massive stellar cluster Westerlund 1. I. Parallax method using Gaia-EDR3
• Distance and age of the massive stellar cluster Westerlund 1. II. The eclipsing binary W36
• On the hadronic origin of the very high energy $\gamma$-ray emission surrounding the young massive stellar cluster Westerlund 1
• Quantifying Systematic Age Discrepancies in Very Young Star Clusters