Planck Cold Clumps in the λ Orionis Complex. I : Discovery of an Extremely Young Class 0 Protostellar Object and a Proto-brown Dwarf Candidate in the Bright-rimmed Clump PGCC G192.32-11.88
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Author
Liu, T.
Zhang, Q.
Kim, K.-T.
Wu, Y.
Lee, C.W.
Lee, J.-E.
Tatematsu, K.
Choi, M.
Juvela, M.
Thompson, M.A.
Goldsmith, P.F.
Liu, S.Y.
Naomi, H.
Koch, P.
Henkel, C.
Sanhueza, P.
He, J.
Rivera-Ingraham, A.
Wang, K.
Cunningham, M.R.
Tang, Y.-W.
Lai, S.-P.
Yuan, J.
Li, D.
Fuller, G.
Kang, M.
Nguyen Luong, Q.
Liu, H.B.
Ristorcelli, I.
Yang, J.
Xu, Y.
Hirota, T.
Mardones, D.
Qin, S.-L.
Chen, H.-R.
Kwon, W.
Meng, F.
Zhang, H.
Kim, M.-R.
Yi, H.-W.
Attention
2299/16805
Abstract
We are performing a series of observations with ground-based telescopes toward Planck Galactic cold clumps (PGCCs) in the λ Orionis complex in order to systematically investigate the effects of stellar feedback. In the particular case of PGCC G192.32-11.88, we discovered an extremely young Class 0 protostellar object (G192N) and a proto-brown dwarf candidate (G192S). G192N and G192S are located in a gravitationally bound bright-rimmed clump. The velocity and temperature gradients seen in line emission of CO isotopologues indicate that PGCC G192.32-11.88 is externally heated and compressed. G192N probably has the lowest bolometric luminosity (˜0.8 {L}⊙ ) and accretion rate (6.3 × 10-7 {M}⊙ yr-1) when compared with other young Class 0 sources (e.g., PACS Bright Red Sources) in the Orion complex. It has slightly larger internal luminosity (0.21 ± 0.01 {L}⊙ ) and outflow velocity (˜14 km s-1) than the predictions of first hydrostatic cores (FHSCs). G192N might be among the youngest Class 0 sources, which are slightly more evolved than an FHSC. Considering its low internal luminosity (0.08 ± 0.01 {L}⊙ ) and accretion rate (2.8 × 10-8 {M}⊙ yr-1), G192S is an ideal proto-brown dwarf candidate. The star formation efficiency (˜0.3%-0.4%) and core formation efficiency (˜1%) in PGCC G192.32-11.88 are significantly smaller than in other giant molecular clouds or filaments, indicating that the star formation therein is greatly suppressed owing to stellar feedback.