Fragmentation of vertically stratified gaseous layers: monolithic or coalescence-driven collapse

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F17%3A00484223" target="_blank" >RIV/67985815:_____/17:00484223 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1093/mnras/stw3354" target="_blank" >http://dx.doi.org/10.1093/mnras/stw3354</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/mnras/stw3354" target="_blank" >10.1093/mnras/stw3354</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Fragmentation of vertically stratified gaseous layers: monolithic or coalescence-driven collapse

Popis výsledku v původním jazyce

We investigate, using 3D hydrodynamic simulations, the fragmentation of pressure-confined, vertically stratified, self-gravitating gaseous layers. The confining pressure is either thermal pressure acting on both surfaces or thermal pressure acting on one surface and ram pressure on the other. In the linear regime of fragmentation, the dispersion relation we obtain agrees well with that derived by Elmegreen & Elmegreen, and consequently deviates from the dispersion relations based on the thin shell approximation or pressure assisted gravitational instability. In the non-linear regime, the relative importance of the confining pressure to the self-gravity is a crucial parameter controlling the qualitative course of fragmentation. When confinement of the layer is dominated by external pressure, self-gravitating condensations are delivered by a two-stage process: first the layer fragments into gravitationally bound but stable clumps, and then these clumps coalesce until they assemble enough mass to collapse. In contrast, when external pressure makes a small contribution to confinement of the layer, the layer fragments monolithically into gravitationally unstable clumps and there is no coalescence. This dichotomy persists whether the external pressure is thermal or ram. We apply these results to fragments forming in a shell swept up by an expanding H II region, and find that, unless the swept-up gas is quite hot or the surrounding medium has low density, the fragments have low mass (less than or similar to 3M(circle dot)), and therefore they are unlikely to spawn stars that are sufficiently massive to promote sequential self-propagating star formation.

Název v anglickém jazyce

Fragmentation of vertically stratified gaseous layers: monolithic or coalescence-driven collapse

Popis výsledku anglicky

We investigate, using 3D hydrodynamic simulations, the fragmentation of pressure-confined, vertically stratified, self-gravitating gaseous layers. The confining pressure is either thermal pressure acting on both surfaces or thermal pressure acting on one surface and ram pressure on the other. In the linear regime of fragmentation, the dispersion relation we obtain agrees well with that derived by Elmegreen & Elmegreen, and consequently deviates from the dispersion relations based on the thin shell approximation or pressure assisted gravitational instability. In the non-linear regime, the relative importance of the confining pressure to the self-gravity is a crucial parameter controlling the qualitative course of fragmentation. When confinement of the layer is dominated by external pressure, self-gravitating condensations are delivered by a two-stage process: first the layer fragments into gravitationally bound but stable clumps, and then these clumps coalesce until they assemble enough mass to collapse. In contrast, when external pressure makes a small contribution to confinement of the layer, the layer fragments monolithically into gravitationally unstable clumps and there is no coalescence. This dichotomy persists whether the external pressure is thermal or ram. We apply these results to fragments forming in a shell swept up by an expanding H II region, and find that, unless the swept-up gas is quite hot or the surrounding medium has low density, the fragments have low mass (less than or similar to 3M(circle dot)), and therefore they are unlikely to spawn stars that are sufficiently massive to promote sequential self-propagating star formation.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/GAP209%2F12%2F1795" target="_blank" >GAP209/12/1795: Tvorba hvězd aktivovaná expandujícími obálkami</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

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

Název periodika

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

e-ISSN

—

Svazek periodika

466

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

19

Strana od-do

4423-4441

Kód UT WoS článku

000402849400048

EID výsledku v databázi Scopus

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