Astrophys. J., Suppl. Ser., 236, 51-51 (2018/June-0)
Planck Cold Clumps in the λ Orionis complex. II. Environmental effects on core formation.
YI H.-W., LEE J.-E., LIU T., KIM K.-T., CHOI M., EDEN D., EVANS II N.J., DI FRANCESCO J., FULLER G., HIRANO N., JUVELA M., KANG S.-J., KIM G., KOCH P.M., LEE C.W., LI D., LIU H.-Y.B., LIU H.-L., LIU S.-Y., RAWLINGS M.G., RISTORCELLI I., SANHUEZA P., SOAM A., TATEMATSU K., THOMPSON M., TOTH L.V., WANG K., WHITE G.J., WU Y., YANG Y.-L. (The JCMT Large Program "SCOPE" Collaboration) (The TRAO Key Science Program "TOP" Collaboration)
Abstract (from CDS):
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 HII region. PGCCs in the λ Orionis cloud have higher dust temperatures (Td = 16.13 ± 0.15 K) and lower values of dust emissivity spectral index (β = 1.65 ± 0.02) than PGCCs in the Orion A (Td = 13.79 ± 0.21 K, β = 2.07 ± 0.03) and Orion B (Td = 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) x 1022 cm–2, number density n(H2) = (2.9 ± 0.4) x 105 cm–3, and mass Mcore = 1.0 ± 0.3 M☉ compared to the cores in the Orion A [R = 0.11 pc, N(H2) = (2.3 ± 0.3) x 1023 cm–2, n(H2) = (3.8 ± 0.5) x 105 cm–3, and Mcore = 2.4 ± 0.3 M☉] and Orion B [R = 0.16 pc, N(H2) = (3.8 ± 0.4) x 1023 cm–2, n(H2) = (15.6 ± 1.8) x 105 cm–3, and Mcore = 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 HII 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.
© 2018. The American Astronomical Society. All rights reserved.
ISM: clouds - stars: formation - submillimeter: ISM
Status at CDS
Examining the need for a new acronym. // Large table(s) of objects being ingested in VizieR.
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