Star cluster ‘infant mortality’ in the Small Magellanic Cloud (Redivivus)

• Published in: Monthly notices of the Royal Astronomical Society Vol. 383; no. 3; pp. 1000 - 1006
• Main Authors: De Grijs, Richard, Goodwin, Simon P.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.2008; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Astrophysics; Cosmology; Earth, ocean, space; Exact sciences and technology; galaxies: star clusters; globular clusters: general; Magellanic Clouds; open clusters and associations: general; Star & galaxy formation; stellar dynamics; Theory; Magellanic Clouds; stellar dynamics; open clusters and associations: general; globular clusters: general; galaxies: star clusters; Cluster evolution; Mass distribution; Open clusters; Stellar evolution; Globular clusters; Star clusters; Galaxy clusters; Small Magellanic Cloud; Age; Stellar dynamics
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2007.12509.x

The early evolution of star clusters in the Small Magellanic Cloud (SMC) has been the subject of significant recent controversy, particularly regarding the importance and length of the earliest, largely mass-independent disruption phase (referred to as ‘infant mortality’). Here, we take a fresh approach to the problem, using an independent, homogeneous data set of UBVR imaging observations, from which we obtain the SMC's cluster age and mass distributions in a self-consistent manner. We conclude that the (optically selected) SMC star cluster population has undergone at most ∼30 per cent (1σ) infant mortality between the age range from about (3–10) Myr, to that of approximately (40–160) Myr. We rule out a 90 per cent cluster mortality rate per decade of age (for the full age range up to 109 yr) at a >6σ level. We independently affirm this scenario based on the age distribution of the SMC cluster sample.