Ruprecht 147: a paradigm of dissolving star cluster

Abstract

We employed recent Gaia/DR2 data to investigate the dynamical status of the nearby (300 pc), old (2.5 Gyr) open cluster Ruprecht~147. We found prominent leading and trailing tails of stars along the cluster orbit, which demonstrates that Ruprecht~147 is losing stars at fast pace. Star counts indicate the cluster has a core radius of 33.3 arcmin, and a tidal radius of 137.5 arcmin. The cluster also possesses an extended corona, which cannot be reproduced by a simple King model. We computed the present-day cluster mass using its luminosity and mass function, and derived an estimate of 234$\pm$52 $M_{\odot }$. We also estimated the cluster original mass using available recipes extracted from N-body simulations obtaining a mass at birth of 50000$\pm$6500 $M_{\odot }$. Therefore dynamical mass loss, mostly caused by tidal interaction with the Milky Way, reduced the cluster mass by about 99\%. We then conclude that Ruprecht~147 is rapidly dissolving into the general Galactic disc.

arXiv comment13 pages, 10 figure, in press in the Astronomical Journal

References in corpus (19)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• Dynamical evolution of star clusters in tidal fields
• The extended tails of Palomar 5: A ten degree arc of globular cluster tidal debris
• Star cluster disruption by giant molecular clouds
• Star Cluster Formation and Disruption Time-Scales -- I. An empirical determination of the disruption time of star clusters in four galaxies
• Disruption time scales of star clusters in different galaxies
• Lifetimes of tidally limited star clusters with different radii
• Whiting 1: the youngest globular cluster associated with the Sgr dSph
• The intermediate-age open cluster NGC 2158
• Evidence of tidal distortions and mass loss from the old open cluster NGC 6791
• Ruprecht 147: The oldest nearby open cluster as a new benchmark for stellar astrophysics
• The chemical composition of the oldest nearby open cluster Ruprecht 147
• Open-cluster density profiles derived using a kernel estimator
• A new compact young moving group around V1062 Sco
• VISION - Vienna Survey in Orion II. Infrared extinction in Orion A
• On the mass of the Galactic star cluster NGC 4337
• UBVI CCD photometry and star counts in 9 inner disk Galactic star clusters

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