The most massive stars in very young star clusters with a limited mass: Evidence favours significant self-regulation in the star formation processes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F23%3A10476050" target="_blank" >RIV/00216208:11320/23:10476050 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=fsmIdS~GN3" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=fsmIdS~GN3</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202244919" target="_blank" >10.1051/0004-6361/202244919</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The most massive stars in very young star clusters with a limited mass: Evidence favours significant self-regulation in the star formation processes

Popis výsledku v původním jazyce

The stellar initial mass function (IMF) is commonly interpreted to be a scale-invariant probability density distribution function (PDF) such that many small clusters yield the same IMF as one massive cluster of the same combined number of stars. Observations of the galaxy-wide IMF challenge this as dwarf galaxies do not form as many massive stars as expected. This indicates a highly self-regulated star formation process in which stellar masses are not stochastically sampled from the IMF and are instead related to the environment of star formation. Here, we study the nature of star formation using the relation between the most massive star born in a star cluster and its parental stellar cluster mass (the m(max) - M-ecl relation). This relation has been argued to be a statistical effect if stars are sampled randomly from the IMF. By comparing the tightness of the observed m(max) - M-ecl distribution with synthetic star clusters with stochastically sampled stellar masses, we find that the expected dispersion of the mock observations is much larger than the observed dispersion. Assuming that m(max) and M-ecl uncertainties from the literature are correct, our test rejects the hypothesis that the IMF is a PDF at a more than 4.5 sigma confidence level. Alternatively, we provide a deterministic stellar mass sampling tool that reproduces the observed m(max) - M-ecl distribution and compares well with the luminosities of star-forming molecular clumps. In addition, we find that there is a significant flattening of the m(max) - M-ecl relation near m(max) = 13 M-?. This may suggest strong feedback of stars more massive than about 13 M-?, and/or that the ejections of the most massive stars from young clusters in the mass range 63 to 400 M-? are likely important physical processes in forming clusters.

Název v anglickém jazyce

The most massive stars in very young star clusters with a limited mass: Evidence favours significant self-regulation in the star formation processes

Popis výsledku anglicky

The stellar initial mass function (IMF) is commonly interpreted to be a scale-invariant probability density distribution function (PDF) such that many small clusters yield the same IMF as one massive cluster of the same combined number of stars. Observations of the galaxy-wide IMF challenge this as dwarf galaxies do not form as many massive stars as expected. This indicates a highly self-regulated star formation process in which stellar masses are not stochastically sampled from the IMF and are instead related to the environment of star formation. Here, we study the nature of star formation using the relation between the most massive star born in a star cluster and its parental stellar cluster mass (the m(max) - M-ecl relation). This relation has been argued to be a statistical effect if stars are sampled randomly from the IMF. By comparing the tightness of the observed m(max) - M-ecl distribution with synthetic star clusters with stochastically sampled stellar masses, we find that the expected dispersion of the mock observations is much larger than the observed dispersion. Assuming that m(max) and M-ecl uncertainties from the literature are correct, our test rejects the hypothesis that the IMF is a PDF at a more than 4.5 sigma confidence level. Alternatively, we provide a deterministic stellar mass sampling tool that reproduces the observed m(max) - M-ecl distribution and compares well with the luminosities of star-forming molecular clumps. In addition, we find that there is a significant flattening of the m(max) - M-ecl relation near m(max) = 13 M-?. This may suggest strong feedback of stars more massive than about 13 M-?, and/or that the ejections of the most massive stars from young clusters in the mass range 63 to 400 M-? are likely important physical processes in forming clusters.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

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

Název periodika

Astronomy &amp; Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

670

Číslo periodika v rámci svazku

únor

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

16

Strana od-do

A151

Kód UT WoS článku

000981621400005

EID výsledku v databázi Scopus

2-s2.0-85148677141