Condition for low-mass star formation in shock-compressed metal-poor clouds
arXiv:1807.05334 · doi:10.1093/mnras/sty1911
Abstract
Shocks may have been prevalent in the early Universe, associated with virialization and supernova explosions, etc. Here, we study thermal evolution and fragmentation of shock-compressed clouds, by using a one-zone model with detailed thermal and chemical processes. We explore a large range of initial density (1-1e5 /cm^3), metallicity (0-1e-2 Z_sun), UV strength (0-500 times Galactic value), and cosmic microwave background temperature (10 and 30 K). Shock-compressed clouds contract isobarically via atomic and molecular line cooling, until self-gravitating clumps are formed by fragmentation. If the metals are only in the gas-phase, the clump mass is higher than ~ 3 M_sun in any conditions we studied. Although in some cases with a metallicity higher than ~ 1e-3 Z_sun, re-fragmentation of a clump is caused by metal-line cooling, this fragment mass is higher than ~ 30 M_sun. On the other hand, if about half the mass of metals is condensed in dust grains, as in the Galactic interstellar medium, dust cooling triggers re-fragmentation of a clump into sub-solar mass pieces, for metallicities higher than ~ 1e-5 Z_sun. Therefore, the presence of dust is essential in low-mass (< M_sun) star formation from a shock-compressed cloud.
15 pages, 8 figures, accepted for publication in MNRAS
References in corpus (22)
- Protostar Formation in the Early Universe
- An extremely primitive halo star
- The Mass Spectrum of the First Stars
- Fragmentation of star-forming clouds enriched with the first dust
- Can Supermassive Black Holes Form in Metal-Enriched High-Redshift Protogalaxies ?
- The First Galaxies: Assembly, Cooling and the Onset of Turbulence
- Resolving the Formation of Protogalaxies. II. Central Gravitational Collapse
- Resolving the Formation of Protogalaxies. I. Virialization
- Formation of an embryonic supermassive star in the first galaxy
- Limits on Pop III star formation with the most iron-poor stars
- Decoding the stellar fossils of the dusty Milky Way progenitors
- Dust-cooling--induced Fragmentation of Low-metallicity Clouds
- Where does galactic dust come from?
- J0023+0307: A mega metal-poor dwarf star from SDSS/BOSS
- Gravitational collapse and the thermal evolution of low-metallicity gas clouds in the early Universe
- Low-mass star formation triggered by early supernova explosions
- Thermal instability and multi-phase interstellar medium in the first galaxies
- Physical Mechanism for the Intermediate Characteristic Stellar Mass in the Extremely Metal-poor Environments
- Conditions for HD Cooling in the First Galaxies Revisited: Interplay between Far-Ultraviolet and Cosmic Ray Feedback in Population III Star Formation
- The formation of the primitive star SDSS J102915+172927: effect of the dust mass and the grain-size distribution
- Do Stellar Winds Prevent the Formation of Supermassive Stars by Accretion?
- Fates of the dense cores formed by fragmentation of filaments: do they fragment again or not?