Revisiting the population of Galactic open clusters

By A. Piskunov, N. Kharchenko, S. Röser, E. Schilbach, R. Scholz. 2005

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We present results of a study of the galactic open cluster population based on the all-sky catalogue ASCC-2.5 (I/280A) compiled from Tycho-2, Hipparcos and other catalogues. The sample of optical clusters from ASCC-2.5 is complete up to about 850 pc from the Sun. The symmetry plane of the clusters' distribution is determined to be at Z 0 = -22 ± 4 pc, and the scale height of open clusters is only 56 ± 3 pc. The total surface density and volume density in the symmetry plane are Σ = 114 kpc -2 and D(Z 0 ) = 1015 kpc -3 , respectively. We find the total number of open clusters in the Galactic disk to be of order of 10 5 at present. Fluctuations in the spatial and velocity distributions are attributed to the existence of four open cluster complexes (OCCs) of different ages containing up to a few tens of clusters. Members in an OCC show the same kinematic behaviour, and a narrow age spread. We find, that the youngest cluster complex, OCC 1 (log t < 7.9), with 19 deg inclination to the Galactic plane, is apparently a signature of Gould's Belt. The most abundant OCC 2 complex has moderate age (log t 8.45). The clusters of the Perseus-Auriga group, having the same age as OCC 2, but different kinematics are seen in breaks between Perseus-Auriga clouds. The oldest (log t 8.85) and sparsest group was identified due to a large motion in the Galactic anticentre direction. Formation rate and lifetime of open clusters are found to be 0.23 ± 0.03 kpc -2 Myr -1 and 322 ± 31 Myr, respectively. This implies a total number of cluster generations in the history of the Galaxy between 30 to 40. We estimate that less than about 10% of the total Galactic stellar disk population has ever passed an open cluster membership.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/6a687a8c184caee1d81de9eab6e85058ec1e25de

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Citations in the corpus

Global survey of star clusters in the Milky Way II. The catalogue of basic parameters (2013, methodology): “The curves were computed with the corresponding parameters from COCD (see Piskunov et al. 2006) based on the Hipparcos data.”
Astrophysical supplements to the ASCC‐2.5: Ia. Radial velocities of ∼55000 stars and mean radial velocities of 516 Galactic open clusters and associations (2007, methodology): “For the computation of these curves we used the Solar motion components and Oort constants as obtained from the sample of 650 clusters studied in Piskunov et al. (2006).”
Star cluster disruption by giant molecular clouds (2006, methodology): “For σcn we take 10 kms−1, based on observations of GMCs in the solar neighbourhood (Stark & Brand 1989) and open clusters (Piskunov et al. 2006).”
The Bar and Spiral Structure Legacy (BeSSeL) Survey: Mapping the Milky Way with VLBI Astrometry† (2011, background): “Mignard (2000) and Piskunov et al. (2006) already favored a significantly higher value of V , in the range of∼12 km s−1.”
Young Massive Star Clusters (2010, background): “With an open cluster birth rate of 0.2–0.5Myr−1 kpc−2 (Battinelli & Capuzzo-Dolcetta 1991, Piskunov et al. 2006), the implied total star formation rate in open clusters is∼ 2×102M⊙ Myr−1 kpc−2.”
A Gaia DR2 view of the open cluster population in the Milky Way (2018, methodology): “…their ages and distances can be estimated in a relatively simple albeit model-dependent way by means of photometry, making them convenient tracers of the structure of the Milky Way (see e.g. Janes & Adler 1982; Dias & Lépine 2005; Piskunov et al. 2006; Moitinho 2010; Buckner & Froebrich 2014).”