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Journal Paper

전체
Planck Cold Clumps in the λ Orionis Complex. II. Environmental Effects on CoreFormation SCI
  • HeeWeon Yi;JeongEun Lee;Tie Liu;Kee-Tae Kim;Choi, Minho;David Eden;Evans, Neal J. II;Kang, Sung-Ju;Gwanjeong Kim;Chang Won Lee;Archana Soam;James Di Francesco;Gary Fuller;N. Hirano;Mika Juvela;Patrick M. Koch;Di Li;H.Y. B. Liu;HongLi Liu;ShengYuan Liu;Mark G. Rawlings;I. Ristorcelli;Patrico Sanhueza;Kenichi Tatematsu;L. V. Toth;Mark Thompson;Ke Wang;Glenn J. White;Yuefang Wu;YaoLun Yang
  • 2018-06-20
  • THE ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 236 2 : 51-1~51-23
Based on the 850 μm dust continuum data from SCUBA-2 at James Clerk Maxwell Telescope (JCMT), we compare overall properties of Planck Galactic Cold Clumps (PGCCs) in the λ Orionis cloud to those of PGCCs in the Orion A and B clouds. The Orion A and B clouds are well-known active star-forming regions, while the λ Orionis cloud has a different environment as a consequence of the interaction with a prominent OB association and a giant H II region. PGCCs in the λ Orionis cloud have higher dust temperatures (T d = 16.13 ± 0.15 K) and lower values of dust emissivity spectral index (β = 1.65 ± 0.02) than PGCCs in the Orion A (T d = 13.79 ± 0.21 K, β = 2.07 ± 0.03) and Orion B (T d = 13.82 ± 0.19 K, β = 1.96 ± 0.02) clouds. We find 119 substructures within the 40 detected PGCCs and identify them as cores. Out of a total of 119 cores, 15 cores are discovered in the λ Orionis cloud, while 74 and 30 cores are found in the Orion A and B clouds, respectively. The cores in the λ Orionis cloud show much lower mean values of size R = 0.08 pc, column density N(H2) = (9.5 ± 1.2) × 1022 cm?2, number density n(H2) = (2.9 ± 0.4) × 105 cm?3, and mass M core = 1.0 ± 0.3 M ⊙ compared to the cores in the Orion A [R = 0.11 pc, N(H2) = (2.3 ± 0.3) × 1023 cm?2, n(H2) = (3.8 ± 0.5) × 105 cm?3, and M core = 2.4 ± 0.3 M ⊙] and Orion B [R = 0.16 pc, N(H2) = (3.8 ± 0.4) × 1023 cm?2, n(H2) = (15.6 ± 1.8) × 105 cm?3, and M core = 2.7 ± 0.3 M ⊙] clouds. These core properties in the λ Orionis cloud can be attributed to the photodissociation and external heating by the nearby H II region, which may prevent the PGCCs from forming gravitationally bound structures and eventually disperse them. These results support the idea of negative stellar feedback on core formation.