Dense molecular cloud cores as a source of micrometer-sized grains in galaxies

摘要: Abstract Coreshine in dense molecular cloud cores (dense cores) is interpreted as evidence for micrometer-sized grains (referred to very large grains, VLGs). VLGs may have a significant influence on the total dust amount and extinction curve. We estimate abundance of Galaxy, assuming that are site VLG formation. find relative mass roughly ϕ ~ 0.01 ( 1 − e ) / τ SF 5 × 10 9 year f 0.5 t shat 8 , where star formation efficiency cores, timescale gas consumption by formation, fraction eventually coagulated into lifetime (determined shattering). Adopting their typical values we obtain 0.02 – 0.09 . This well below value detected heliosphere Ulysses Galileo, which means local enhancement solar neighborhood required if originate from cores. also show effects curve negligible even with upper above range, If adopt an extreme value, close inferred spacecraft data, still range variation Galactic curves, but not diffuse ISM.