Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
권호 표지

A STUDY OF LYNDS 1299 DARK CLOUD

  • RYU OK-KYUNGI (Department of Astronomy and Space Science, Chungnam National University) ;
  • LEE YOUNGUNG (Korea Astronomy Observatory, Taeduk Radio Astronomy Observatory)
  • Published : 1998.10.01
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Abstract

We have mapped about 1.5 square degree regions of Lynds 1299, a well isolated dark cloud in the Outer Galaxy (l = $122^{\circ}$, b = $-7^{\circ}$), in the J = 1- 0 transition of $^{12}CO$ and $^{13}CO$ with the 13.7 m radio telescope at Taeduk Radio Astronomy Observatory (TRAO). We found that there are two velocity components in the molecular emission, at $V_{LSR} = -52 km S^{-1}$ (Cloud A) and -8.8 km $s^{-1}$ (Cloud B), respectively. We have derived physical parameters of two molecular clouds and discussed three different mass estimate techniques. We found that there are large discrepancies between the virial and LTE mass estimates for both clouds. The large virial mass estimate reflects the fact that both are not gravitationally bound. We adopt the mass of $5.6 {\times}10^3 \;M{\bigodot}$ for Cloud A and $1.2{\times}10^3 \;M{\bigodot}$) for Cloud B using conversion factor. Cloud A is found to be associated with a localized star forming site, and its morphology is well matching with that of far-infrared (FIR) dust emission. It shows a clear ring structure with an obvious velocity gradient. We suggest that it may be a remnant cloud from a past episode of massive star formation. Cloud B is found to be unrelated to Cloud A (d = 800 pc) and has no specific velocity structure. The average dust color temperature of the uncontaminated portion of Cloud A is estimated to be 24$\~$27.4 K. The low dust temperature may imply that there is no additional internal heating source within the cloud. The heating of the cloud is probably dominated by the interstellar radiation field except the region directly associated with the new-born B5 star. Overall, the dust properties of Cloud A are similar to those of normal dark cloud even though it does have star forming activity.

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References

  1. A&A v.139 Bloemen, J. B. G. M.;Caraveo, P. A.;Hermsen, Lebrun, F.;Maddalena, R. J.;Strong, A. W.;Thaddeus, P.
  2. Interstellar Process Blemen, J. B. G. M.;D. J. Hollenbach(ed.);H. A. Thronson, Jr.(ed.)
  3. ARA&A v.27 Bloemen, J. B. G. M.
  4. ApJ v.330 Boulanger, F.;Perault, M.
  5. ApJ v.224 Carpenter, J. M.;Sneel, R. L.;Schloerb, F. P.
  6. AAR v.1 Cox, P.;Mezger, P. G.
  7. ApJS v.37 Dickman, R. L.
  8. ApJ v.321 Heyer, M. H.;Vrba, F. J.;Snell, R. L.;Schloerb, F. P.;Strom. S. E.;Goldsmith, P. F.;Strom, K. M.
  9. J. Roy. Ast. Soc. v.24 Hildebrand, R. H.
  10. ApJ v.250 Kutner, M. C.;Ulich, B. L.
  11. ApJ v.337 Langer, W.;Wilson, R. W.;Goldsmith, P. F.
  12. ApJ v.281 Lebrun, F.;Bennet, K.;Bignami, G.;Bloemen, J. B. G. M.;Buccheri, R.
  13. ApJ v.355 Lee, Y.;Snell, R. L.;Dickman, R. L.
  14. Ph. D. Dissertation, University of Massachusetts Lee, Y.
  15. ApJ v.432 Lee, Y.;Snell, R. L.;Dickman, R. L.
  16. Publications of the Korean Astronomy Society v.9 no.1 Lee, Y.
  17. Journal of the Korean Astronomy Society v.27 no.2 Lee, Y.
  18. Ph.D. thesis, Univ. New York Mooney, T.
  19. A&A v.131 Nekel, T.;Staude, H. J.
  20. Interstellar Process Scoville, N. Z;Sanders, D. B.;D. J. Hollenbach(ed.);H. A. Thronson, Jr.(ed.)
  21. ApJ v.337 Snell, R. L.;Heyer, M. H.;Schloerb, F. P.
  22. A&AS v.8 Weaver, H. F.;Williams, D. R. W.
  23. ApJS v.110 Yonekura, Y.;Dobashi, K.;Mizuno, A.;Ogawa, H.;Fukui, Y.
  24. ApJ v.306 Dickman, R. L.;Snell, R. L.;Schloerb, F. P.