Modes of Multiple Star Formation

By Fred C. Adams, P. Myers. 2001

132 citations recorded by the source corpus.

This paper argues that star-forming environments should be classified into finer divisions than the traditional isolated and clustered modes. Using the observed set of Galactic open clusters and theoretical considerations regarding cluster formation, we estimate the fraction of star formation that takes place within clusters. We find that less than ~10% of the stellar population originates from star-forming regions destined to become open clusters, confirming earlier estimates. The smallest clusters included in the observational surveys (having at least N ~ 100 members) roughly coincide with the smallest stellar systems that are expected to evolve as clusters in a dynamical sense. We show that stellar systems with too few members N < N* have dynamical relaxation times that are shorter than their formation times (~1-2 Myr), where the critical number of stars N* ≈ 100. Our results suggest that star formation can be characterized by (at least) three principal modes: (I) isolated singles and binaries, (II) groups (N < N*), and (III) clusters (N > N*). Many—if not most—stars form through the intermediate mode in stellar groups with 10 < N < 100. Such groups evolve and disperse much more rapidly than do open clusters; groups also have a low probability of containing massive stars and are unaffected by supernovae and intense ultraviolet radiation fields. Because of their short lifetimes and small stellar membership, groups have relatively little effect on the star formation process (on average) compared to larger open clusters.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/7ed07bb39c8126891292ffc62e66d2c3e2343664

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Citations in the corpus

The initial conditions of star formation in the Ophiuchus main cloud: Kinematics of the protocluster condensations , (2007, background): “While most stars are believed to form in clusters (e.g. Adams & Myers 2001; Lada & Lada 2003), our present theoretical understanding of the star formation process is essentially limited to isolated dense cores and protostars (e.g. Shu et al. 1987, 2004).”
Clustered and Triggered Star Formation in W5: Observations with Spitzer (2008, background): “Small groups (N 36) have short relaxation times relative to their crossing times and, once the gas is removed, will not remain visible as clusters for much longer than this (Adams & Myers 2001).”
Early Evolution of Stellar Groups and Clusters: Environmental Effects on Forming Planetary Systems (2005, background): “The radiation from the parent star can drive mass loss from its planet-forming disk and thereby affect planet formation (Shu et al. 1993), but this effect is often dominated by radiation from the background star cluster (Johnstone et al. 1998; Adams & Myers 2001).”
Probing the formation of intermediate- to high-mass stars in protoclusters - A detailed millimeter study of the NGC 2264 clumps (2005, background): “While most stars are believed to form in clusters (e.g. Adams & Myers 2001, Lada & Lada 2003), our present theoretical understanding of the star formation process is essentially limited to isolated dense cores and protostars (e.g. Shu et al. 1987, 2004).”
Physical Processes in the Interstellar Medium (2014, background): “This appears to be the most common mode of star formation in the solar neighborhood (Adams & Myers, 2001).”
The Initial Configuration of Young Stellar Clusters: A K-Band Number Counts Analysis of the Surface Density of Stars (2004, background): “Analytical investigations and numerical simulations of the dynamics of young clusters following rapid expulsion of their natal gas have shown that dynamical expansion and dissolution can occur on short time scales in young clusters (Adams & Myers 2001; Kroupa, Petr, & McCaughrean 1999).”
The stellar and sub-stellar IMF of simple and composite populations (2011, background): “2.6), and with the independent result derived from an analysis of the distribution of local star clusters that most stars appear to stem from such modest clusters (Adams & Myers 2001).”
The Variation of Integrated Star Initial Mass Functions among Galaxies (2005, background): “They also conclude that 80% of newly formed open clusters will dissolve in less than 20 Myr.”
The effects of fly‐bys on planetary systems (2010, background): “At least 10 per cent of stars form in such clusters, while the remaining form either in clusters which disperse due to gas removal or in small groups or associations (e.g. van den Bergh 1981; Elmegreen & Clemens 1985; Battinelli & Capuzzo-Dolcetta 1991; Adams & Myers 2001).”
The relation between the most-massive star and its parental star cluster mass (2009, background): “As the bulk of the galactic field star populations are probably made from dissolving star clusters (Kroupa 1995; Lada & Lada 1995, 2003; Adams & Myers 2001; Allen et al. 2007), understanding the stellar distribution in galaxies presupposes knowledge of the IMF in star clusters.”
Embedded Clusters in Molecular Clouds (2003, methodology): “Another indication of the robustness of the IMF is found in the observations of NGC 3603, perhaps the most luminous and richest young cluster in the Galaxy.”
Photoevaporation of Circumstellar Disks Due to External Far-Ultraviolet Radiation in Stellar Aggregates (2004, methodology): “For example, at a distance of 0.3 pc, a single main-sequence star of mass M ¼ 8:7 M will produce an FUV radiation field with G0 2000 (Parravano et al. 2003).5 According to the standard IMF, a stellar aggregate with N 200 will have a 50/50 chance of producing a star this large (Adams & Myers 2001).”
The Birth Environment of the Solar System (2010, background): “For larger clusters with membership N ≥ 100, the background cluster environment provides more ionizing photons to the solar nebula than the early Sun itself (Adams & Myers 2001).”