HII regions; ISM : individual (DEM L106); Magellanic Clouds; stars : emission-line, Be; stars : mass loss
Abstract :
[en] Narrowband HST WFPC2 images reveal a bow-shock-like halo around the H II region N30B toward the B[e] supergiant Hen S22 located within the larger DEM L106 nebula in the Large Magellanic Cloud. High-dispersion spectra of N30B show a narrow Halpha emission component from the ionized gas; the velocity variations indicate a gas flow of - 5 to - 10 km s(-1) in the vicinity of the H II regions, which is resultant from interactions with Hen S22's stellar wind and responsible for the bow-shock morphology. Spectra of N30B's halo show broad Halpha profiles extending over more than 1000 km s(-1), similar to that of Hen S22, indicating that the halo is a reflection nebula of Hen S22. Broadband morphologies of N30B's halo are also consistent with the reflection nebula interpretation. We use dust-scattering properties and the observed brightnesses of the reflection nebula and Hen S22 to constrain the reflection geometry. The reflected stellar Halpha emission and absorption vary across the reflection nebula as a result of viewing S22's anisotropic wind from different angles. This reflection nebula, together with the edge-on orientation of Hen S22's disk, provides an invaluable opportunity to study the disk and polar winds of a B[e] supergiant.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Chu, You-Hua; University of Illinois > Astronomy Department
Chen, Chang-Hui Rosie; University of Illinois > Astronomy Department
Danforth, Charles; Johns Hopkins University > Department of Physics and Astronomy
Dunne, Bryan C.; University of Illinois > Astronomy Department
Gruendl, Robert A.; University of Illinois > Astronomy Department
Nazé, Yaël ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE)
Oey, Marion Sally; Lowell Observatory
Points, Sean D.; Northwestern University > Department of Physics and Astronomy
Language :
English
Title :
The wind of the B[e] supergiant Henize S22 viewed through a reflection nebula in DEM L106
Publication date :
April 2003
Journal title :
Astronomical Journal
ISSN :
0004-6256
eISSN :
1538-3881
Publisher :
Univ Chicago Press, Chicago, United States - Illinois
Bensammar, S., Friedjung, M., Muratorio, G., & Viotti, R. 1983, A&A, 126, 427
Boumis, P., Meaburn, J., Bryce, M., & Lopez, J. A. 1998, MNRAS, 294, 61
Castañeda, H. O., Vilchez, J. M., & Copetti, M. V. F. 1990, ApJ, 365, 164
Chen, C.-H. R., Chu, Y.-H., Gruendl, R. A., & Points, S. D. 2000, AJ, 119, 1317
Chu, Y.-H. 1983, PASP, 95, 873
Chu, Y.-H., Chang, H.-W., Su, Y.-L., & Mac Low, M.-M. 1995, ApJ, 450, 157
Davies, R. D., Elliott, K. H., & Meaburn, J. 1976, MmRAS, 81, 89
Feast, M. 1999, in IAU Symp. 190, New Views of the Magellanic Clouds, ed. Y.-H. Chu, N. B. Suntzeff, J. E. Hesser, & D. A. Bohlender (San Francisco: ASP), 542
Henize, K. G. 1956, ApJS, 2, 315
Henyey, L. C., & Greenstein, J. L. 1941, ApJ, 93, 70
Lillie, C. F., & Witt, A. N. 1976, ApJ, 208, 64
Lopez, J. A., & Meaburn, J. 1986, Rev. Mexicana Astron. Astrofis., 13, 27
Lucke, P. B., & Hodge, P. W. 1970, AJ, 75, 171
Muratorio, G. 1978, A&AS, 33, 125
Oey, M. S. 1996a, ApJ, 465, 231
_. 1996b, ApJS, 104, 71
Panagia, N. 1973, AJ, 78, 929
Ruiz, M. T., Melnick, J., & Ortiz, P. 1984, ApJ, 285, L19
Schaerer, D., & de Koter, A. 1997, A&A, 322, 598
Smith, N. 2002, Ph.D. thesis, Univ. Minnesota
Zickgraf, F.-J., Humphreys, R. M., Lamers, H. J. G. L. M., Smolinski, J., Wolf, B., & Stahl, O. 1996, A&A, 315, 510