2024/01/04 by Tetsuo Taki, Shigeru Wakita, Taki, Tetsuo +1
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2401.02574
openalex publication_date 2024/01/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The lifetime of mm size dust grains, such as chondrules, in the nominal solar nebula model is limited to ∼ 105 yr due to an inward drift driven by gas drag. However, isotopic and petrological studies on primitive meteorites indicate a discrepancy of \gtrsim 106 yr between the formation time of chondrules and that of chondritic parent bodies. Therefore chondrules should survive for \gtrsim 106 yr in the solar nebula against the inward drift without subsequent growth (i.e., planetesimal formation). Here we investigate the conditions of the solar nebula that are suitable for the long lifetime of chondrule-sized dust particles. We take the turbulent strength, the radial pressure gradient force, and the disk metallicity of the solar nebula as free parameters. For 1 mm-radius-chondrules to survive and keep their size for \gtrsim 106 yr, the suitable condition is a weak turbulence (α∼ 10-6), a flat radial profile (η\lesssim 10-3), and a high metallicity (Z∼ 0.1). This condition is qualitatively consistent with the characteristics of protoplanetary disks suggested by recent observations. We eventually propose that planetesimal formation may be induced by the disk evolution, e.g., the inside-out dispersal of the gas component due to the disk wind.