2013/01/31 by Gen Chiaki, Takaya Nozawa, Naoki Yoshida
Physics and Astronomy · #Accretion (finance) #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Fragmentation (computing) #Grain growth #Grain size #Materials science #Metallicity #Metallurgy #Physics #Star formation #Stars #Stellar, planetary, and galactic studies #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1088/2041-8205/765/1/l3
published as ApJ 765 (2013) L3 · [v1] 5 pages, 4 figures [v2] minor revision, to appear in ApJL
openalex publication_date 2013/02/11 · arxiv created 2013/02/12 · arxiv updated 2013/02/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In a low-metallicity gas, rapid cooling by dust thermal emission is considered to induce cloud fragmentation and play a vital role in the formation of low-mass stars (≲ 1 M ☉ ) in metal-poor environments. We investigate how the growth of dust grains through accretion of heavy elements in the gas phase onto grain surfaces alters the thermal evolution and fragmentation properties of a collapsing gas cloud. We directly calculate grain growth and dust emission cooling in a self-consistent manner. We show that MgSiO 3 grains grow sufficiently at gas densities n H = 10 10 , 10 12 , and 10 14 cm −3 for metallicities Z = 10 −4 , 10 −5 , and 10 −6 Z ☉ , respectively, where the cooling of the collapsing gas cloud is enhanced. The condition for efficient dust cooling is insensitive to the initial condensation factor of pre-existing grains within the realistic range of 0.001–0.1, but sensitive to metallicity. The critical metallicity is Z crit ∼ 10 −5.5 Z ☉ for the initial grain radius and Z crit ∼ 10 −4.5 Z ☉ for . The formation of a recently discovered low-mass star with extremely low metallicity (⩽4.5 × 10 −5 Z ☉ ) could have been triggered by grain growth.