Star formation time-scale in the molecular filament WB 673. Issue 4 (1st November 2022)

• Record Type: Journal Article
• Authors: Ryabukhina, O L; Kirsanova, M S; Henkel, C; Wiebe, D S
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 517:Issue 4(2022)
• Page Start: 4669
• Page End: 4678
• Publication Date: 2022-11-01
• Subjects: stars: formation -- ISM: clouds -- ISM: individual objects (WB89 673, S233-IR) -- ISM: molecules; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac2877
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present the observations of ammonia emission lines toward the interstellar filament WB 673 hosting the dense clumps WB 673, WB 668, S233-IR, and G173.57+2.43. LTE analysis of the lines allows us to estimate gas kinetic temperature (≲30K in all the clumps), number density (7–17 × 10 3 cm −3 ), and ammonia column density (≈1–1.5 × 10 15 cm −2 ) in the dense clumps. We find signatures of collapse in WB 673 and presence of compact spatially unresolved dense clumps in S233-IR. We reconstruct 1D density and temperature distributions in the clumps and estimate their ages using astrochemical modelling. Considering CO, CS, NH3, and N2 H + molecules (plus HCN and HNC for WB 673), we find a chemical age of t chem = 1–3 × 10 5 yrs, providing the best agreement between the simulated and observed column densities in all the clumps. Therefore, we consider t chem as the chemical age of the entire filament. A long preceding low-density stage of gas accumulation in the astrochemical model would break the agreement between the simulated and observed column densities. We suggest that rapid star formation over a ∼10 5 yrs time-scale take place in the filament.