The bound fraction of young star clusters

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10369261" target="_blank" >RIV/00216208:11320/17:10369261 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1051/0004-6361/201629312" target="_blank" >http://dx.doi.org/10.1051/0004-6361/201629312</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201629312" target="_blank" >10.1051/0004-6361/201629312</a>

Result language

angličtina

Original language name

The bound fraction of young star clusters

Original language description

Context. The residual gas within newly formed star clusters is expelled through stellar feedback on timescales &lt;= 1 Myr. The subsequent expansion of the cluster results in an unbinding of a fraction of stars, before the remaining cluster members can re-virialize and form a surviving cluster. Aims. We investigate the bound fraction after gas expulsion as a function of initial cluster mass in stars M-ecl and gauge the influence of primordial mass segregation, stellar evolution and the tidal field at solar distance. We also assess the impact of the star-formation efficiency epsilon(SFE) and gas expulsion velocity v(g). Methods. We perform N-body simulations using Sverre Aarseth&apos;s NBODY7 code, starting with compact clusters in their embedded phase and approximate the gas expulsion by means of an exponentially depleting external gravitational field. We follow the process of re-virialization through detailed monitoring of different Lagrange radii over several Myr, examining initial half-mass radii of 0.1 pc, 0.3 pc and 0.5 pc and M-ecl usually ranging from 5 x 10(3) M-circle dot to 5 x 10(4) M-circle dot. Results. The strong impact of the relation between the gas expulsion timescale and the crossing time means that clusters with the same initial core density can have very di ff erent bound fractions. The adopted epsilon(SFE) = 0.33 in the cluster volume results in a distinct sensitivity to v(g) over a wide mass range, while a variation of epsilon(SFE) can make the cluster robust to the rapidly decreasing external potential. We confirm that primordial mass segregation leads to a smaller bound fraction, its influence possibly decreasing with mass. Stellar evolution has a higher impact on lower mass clusters, but heating through dynamical friction could expand the cluster to a similar extent. The examined clusters expand well within their tidal radii and would survive gas expulsion even in a strong tidal field.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy &amp; Astrophysics [online]

ISSN

1432-0746

e-ISSN

—

Volume of the periodical

600

Issue of the periodical within the volume

duben

Country of publishing house

FR - FRANCE

Number of pages

12

Pages from-to

—

UT code for WoS article

000400754000046

EID of the result in the Scopus database

—