Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-29T18:30:24.142Z Has data issue: false hasContentIssue false
  • English
  • Français

Physical Properties of Molecular Envelopes in Low-Mass Star-Forming Regions

Published online by Cambridge University Press:  25 May 2016

Nagayoshi Ohashi
Nagayoshi Ohashi*
Affiliation:
Academia Sinica Institute of Astronomy & Astrophysics, P.O. Box 1-87, Nankang, Taipei 115, Taiwan

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We have carried out interferometric observations of pre-protostellar and protostellar envelopes in Taurus. Protostellar envelopes are dense gaseous condensations with young stellar objects or protostars, while pre-protostellar envelopes are those without any known young stellar objects. Five pre-protostellar envelopes have been observed in CCS JN=32–21, showing flattened and clumpy structures of the envelopes. The observed CCS spectra show moderately narrow line widths, ~0.1 to ~0.35 km s–1. One pre-protostellar envelope, L1544, shows a remarkable velocity pattern, which can be explained in terms of infall and rotation. Our C18O J=1–0 observations of 8 protostellar envelopes show that they have also flattened structures like pre-protostellar envelopes but no clumpy structures. Four out the eight envelopes show velocity patterns that can be explained by motions of infall (and rotation). Physical properties of pre-protostellar and protostellar envelopes are discussed in detail.

Type
Part 1. Chemistry in Pre-Stellar Cores and Low-Mass Star-Forming Regions
Information
Symposium - International Astronomical Union , Volume 197: Astrochemistry: From Molecular Clouds to Planetary Systems , 2000 , pp. 61 - 70
Copyright
Copyright © Astronomical Society of the Pacific 2000 

References

Adams, F.C., Shu, F.H., & Lada, C.J. 1988, ApJ, 326, 865 Google Scholar
André, P., Ward-Thompson, D., & Motte, F. 1996, A&A, 314, 625 Google Scholar
Beichman, C.A., Myers, P.C., Emerson, J.P., Harris, S., Mathieu, R., Benson, P.J., & Jennings, R.E. 1986, ApJ, 307, 337 Google Scholar
Bergin, E.A. & Langer, W.D. 1997, ApJ, 486, 316 Google Scholar
Bontemps, S., André, P., Terebey, S., & Cabrit, S. 1996, A&A, 311, 858 Google Scholar
Chen, H., Myers, P.C., Ladd, E.F., & Wood, D.O. 1995, ApJ, 445, 377 CrossRefGoogle Scholar
Fuller, G.A. & Myers, P.C. 1992, ApJ, 384, 523 Google Scholar
Goodman, A.A., Barranco, J.A., Wilner, D.J., & Heyer, M.H. 1998, ApJ, 504, 223 Google Scholar
Hayashi, M., Ohashi, N., & Miyama, S.M. 1993, ApJ, 418, L71 Google Scholar
Henriksen, R.N., André, P., & Bontemps, S. 1997, A&A, 323, 549 Google Scholar
Hirahara, Y., Suzuki, H., Yamamoto, S., Kawaguchi, K., Kaifu, N., Ohishi, M., Takano, S., Ishikawa, S., & Masuda, A. 1992, ApJ, 394, 539 CrossRefGoogle Scholar
Kuiper, T.B.H., Langer, W.D., & Velusamy, T. 1996, ApJ, 468, 761 Google Scholar
Langer, W.D., Velusamy, T., Kuiper, T.B.H., Levin, S., Olsen, E., & Migenes, V. 1995, ApJ, 453, L293 Google Scholar
Lay, O.P., Carlstrom, J.E., Hills, R.E., & Phillips, T.G. 1994, ApJ, 434, L75 Google Scholar
Momose, M. 1998, private communication Google Scholar
Momose, M., Ohashi, N., Kawabe, R., Nakano, T., & Hayashi, M. 1998, ApJ, 504, 314 Google Scholar
Moriarty-Schieven, G.H., et al. 2000, in preparation Google Scholar
Mundy, L.G., et al. 1996, ApJ, 464, L169 Google Scholar
Ohashi, N. 1999, in Star Formation 1999, ed. Nakamoto, T., in press Google Scholar
Ohashi, N., Hayashi, M., Ho, P.T.P., & Momose, M. 1997a, ApJ, 475, 211 Google Scholar
Ohashi, N., Hayashi, M., Ho, P.T.P., Momose, M., Tamura, M., Hirano, N., & Sargent, A.I. 1997b, ApJ, 488, 317 Google Scholar
Ohashi, N., Lee, S.-W., Wilner, D.J., & Hayashi, M. 1999, ApJ, 518, L41 Google Scholar
Ohashi, N., et al. 2000, in preparation Google Scholar
Shu, F.H., Adams, F.C., & Lizano, S. 1987, ARA&A, 25, 23 Google Scholar
Suzuki, H., Yamamoto, S., Ohishi, M., Kaifu, N., Ishikawa, S., Hirahara, Y., & Takano, S. 1992, ApJ, 392, 551 Google Scholar
Tafalla, M., Mardones, D., Myers, P.C., Caselli, P., Bachiller, R., & Benson, P.J. 1998, ApJ, 504, 900 Google Scholar
Ward-Thompson, D., Motte, F., & André, P. 1999, MNRAS, 305, 143 Google Scholar
Ward-Thompson, D., Scott, P.F., Hills, R.E., & André, P. 1994, MNRAS, 268, 276 Google Scholar
Willacy, K., Langer, W.D., & Velusamy, T. 1998, ApJ, 507, L171 Google Scholar
Williams, J.P., Myers, P.C., Wilner, D.J., & Di Francesco, J. 1999, ApJ, 13, L61 Google Scholar