Academic Journal
The Dustiest Galactic S Stars: Mid-infrared Spectra from SOFIA/FORCAST
| العنوان: | The Dustiest Galactic S Stars: Mid-infrared Spectra from SOFIA/FORCAST |
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| المؤلفون: | Kathleen E. Kraemer, G. C. Sloan, Ramses M. Ramirez |
| المصدر: | The Astrophysical Journal, Vol 973, Iss 2, p 158 (2024) |
| بيانات النشر: | IOP Publishing |
| سنة النشر: | 2024 |
| المجموعة: | Directory of Open Access Journals: DOAJ Articles |
| مصطلحات موضوعية: | S stars, Infrared spectroscopy, Astrophysics, QB460-466 |
| الوصف: | We present spectra of 12 of the reddest, and hence dustiest, S stars in the Milky Way, observed with the FORCAST grisms on SOFIA. S stars are asymptotic giant branch (AGB) stars with C/O ∼ 1, so their molecular and dust chemistries are dominated by neither O nor C, often leading to atypical spectral features from their molecules and dust grains. All of the stars in our sample have strong dust emission features at 10–11 μ m, but the shape of the feature in most of the stars differs from the shapes commonly observed in either oxygen-rich or carbon-rich AGB stars. Two stars also show the 13 μ m feature associated with crystalline alumina. Two have a water absorption band at ∼6.5–7.5 μ m, and a third has a tentative detection, but only one of these three has the more common SiO absorption band at 7.5 μ m. Three others show a red 6.3 μ m emission feature from complex hydrocarbons consistent with “Class C” objects, and in a fourth it appears at 6.37 μ m, redder than even the standard Class C hydrocarbon feature. Class C spectra typically indicate complex hydrocarbons that have been less processed by UV radiation, resulting in more aliphatic bonds relative to aromatic bonds. None of the S stars show a strong 11.3 μ m hydrocarbon feature, which is also consistent with the presence of aliphatic hydrocarbons. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| Relation: | https://doi.org/10.3847/1538-4357/ad6dfa; https://doaj.org/toc/1538-4357; https://doaj.org/article/ab85eb63ef6a46ff84528910728e49a2 |
| DOI: | 10.3847/1538-4357/ad6dfa |
| الاتاحة: | https://doi.org/10.3847/1538-4357/ad6dfa https://doaj.org/article/ab85eb63ef6a46ff84528910728e49a2 |
| رقم الانضمام: | edsbas.78A3364F |
| قاعدة البيانات: | BASE |
| DOI: | 10.3847/1538-4357/ad6dfa |
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