Filamentary Structures and Star Formation Activity in the Sites S234, V582, and IRAS 05231+3512

Abstract

To investigate ongoing physical processes, we present the results of observations of the sites S234, V582, and IRAS 05231+3512 situated toward l  = 171.°7–174.°1. Based on the CO line data, we find that these sites are not physically connected, and contain at least one filament (with length >7 pc). The observed line masses ( M line,obs ) of the filaments associated with V582 and IRAS 05231+3512 are ∼37 and ∼28 M ⊙ pc −1 , respectively. These filaments are characterized as thermally supercritical, and harbor several clumps. Groups of infrared-excess sources and massive B-type stars are observed toward the filament containing V582, while very little star formation (SF) activity is found around IRAS 05231+3512. Our results favor a radial collapse scenario in the filaments harboring V582 and IRAS 05231+3512. In the site S234, two filaments (i.e., ns1 ( M line,obs ∼ 130 M ⊙ pc −1 ) and ns2 ( M line,obs ∼ 45 M ⊙ pc −1 )) are identified as thermally supercritical. An extended temperature structure at 27–30 K surrounds the relatively cold (∼19 K) ∼8.9 pc long filament ns1. At least four condensations ( M clump ∼ 70–300 M ⊙ ) are seen in ns1, and are devoid of 610 MHz radio emission as observed by the Giant Metrewave Radio Telescope. The filament ns2 hosting clumps is devoid of ongoing SF, and could be at an early stage of fragmentation. Intense SF activity, with an SF efficiency ∼3.3% and SF rate ∼40–20 M ⊙ Myr −1 (for t sf  ∼ 1–2 Myr), is observed in ns1. The feedback of massive stars in S234 seems to explain the observed SF in the filament ns1.