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

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.

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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.

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.