Different modes of star formation

Gravitational collapse of magnetically subcritical cloud

Masahiro Machida, Koki Higuchi, Satoshi Okuzumi

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Star formation in magnetically subcritical clouds is investigated using a three-dimensional non-ideal magnetohydrodynamic simulation. Since rapid cloud collapse is suppressed until the magnetic flux is sufficiently removed from the initially magnetically subcritical cloud by ambipolar diffusion, it takes ≳5-10 tff to form a protostar, where tff is the freefall time-scale of the initial cloud. The angular momentum of the star-forming cloud is efficiently transferred to the interstellar medium before the rapid collapse begins, and the collapsing cloud has a very low angular momentum. Unlike the magnetically supercritical case, no large-scale lowvelocity outflow appears in such a collapsing cloud due to the short lifetime of the first core. Following protostar formation, a very weak high-velocity jet, which has a small momentum and might disappear at a later time, is driven near the protostar, while the circumstellar disc does not grow during the early mass accretion phase. The results show that the star formation process in magnetically subcritical clouds is qualitatively different from that in magnetically supercritical clouds.

Original languageEnglish
Pages (from-to)3080-3094
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume473
Issue number3
DOIs
Publication statusPublished - Jan 1 2018

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gravitational collapse
star formation
protostars
angular momentum
ambipolar diffusion
magnetohydrodynamic simulation
magnetohydrodynamics
magnetic flux
momentum
outflow
accretion
timescale
stars
life (durability)

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Different modes of star formation : Gravitational collapse of magnetically subcritical cloud. / Machida, Masahiro; Higuchi, Koki; Okuzumi, Satoshi.

In: Monthly Notices of the Royal Astronomical Society, Vol. 473, No. 3, 01.01.2018, p. 3080-3094.

Research output: Contribution to journalArticle

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