Spitzer observations of acetylene bands in carbon-rich asymptotic giant branch stars in the Large Magellanic Cloud
| العنوان: | Spitzer observations of acetylene bands in carbon-rich asymptotic giant branch stars in the Large Magellanic Cloud |
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| المؤلفون: | M. Matsuura, P. R. Wood, G. C. Sloan, A. A. Zijlstra, J. Th. Van Loon, M. A. T. Groenewegen, J. A. D. L. Blommaert, M.-R. L. Cioni, M. W. Feast, H. J. Habing, S. Hony, E. Lagadec, C. Loup, J. W. Menzies, L. B. F. M. Waters, P. A. Whitelock |
| المصدر: | Monthly Notices of the Royal Astronomical Society. 371:415-420 |
| بيانات النشر: | Oxford University Press (OUP), 2006. |
| سنة النشر: | 2006 |
| مصطلحات موضوعية: | Physics, Stars, Spitzer Space Telescope, Space and Planetary Science, Metallicity, Spectral energy distribution, Circumstellar dust, Astronomy and Astrophysics, Circumstellar envelope, Astrophysics, Large Magellanic Cloud, Spectral line |
| الوصف: | We investigate the molecular bands in carbon-rich AGB stars in the Large Magellanic Cloud (LMC), using the InfraRed Spectrograph (IRS) on board the Spitzer Space Telescope (SST) over the 5–38 µm range. All 26 low-resolution spectra show acetylene (C2H2) bands at 7 and 14 µm. The hydrogen cyanide (HCN) bands at these wavelengths are very weak or absent. This is consistent with low nitrogen abundances in the LMC. The observed 14 µm C2H2 band is reasonably reproduced by an excitation temperature of 500 K. There is no clear dilution of the 14 µm C2H2 band by circumstellar dust emission. This 14 µm band originates from molecular gas in the circumstellar envelope in these high mass-loss rate stars, in agreement with previous findings for Galactic stars. The C2H2 column density, derived from the 13.7 µm band, shows a gas mass-loss rate in the range 3 ×10 −6 to 5 ×10 −5 M ⊙ yr −1 . This is comparable with the total mass-loss rate of these stars estimated from the spectral energy distribution. Additionally, we compare the line strengths of the 13.7 µm C2H2 band of our LMC sample with those of a Galactic sample. Despite the low metallicity of the LMC, there is no clear difference in the C2H2 abundance among LMC and Galactic stars. This reflects the effect of the 3rd dredge-up bringing self-produced carbon to the surface, leading to high C/O ratios at low metallicity. |
| تدمد: | 1365-2966 0035-8711 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::fe398e15d5587c3982425d51e628511f https://doi.org/10.1111/j.1365-2966.2006.10664.x |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi...........fe398e15d5587c3982425d51e628511f |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 13652966 00358711 |
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