تقرير
SN 2021foa: The 'Flip-Flop' Type IIn / Ibn supernova
| العنوان: | SN 2021foa: The 'Flip-Flop' Type IIn / Ibn supernova |
|---|---|
| المؤلفون: | Farias, D., Gall, C., Narayan, G., Rest, S., Villar, V. A., Angus, C. R., Auchettl, K., Davis, K. W., Foley, R., Gagliano, A., Hjorth, J., Izzo, L., Kilpatrick, C. D., Perkins, H . M. L., Ramirez-Ruiz, E., Ransome, C. L., A., Sarangi., Yarza, R., Coulter, D. A., Jones, D. O., Khetan, N., Rest, A., Siebert, M. R., Swift, J. J., Taggart, K., Tinyanont, S., Wrubel, P., de Boer, T. J. L., Clever, K. E., Dhara, A., Gao, H., Lin, C. -C. |
| سنة النشر: | 2024 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - High Energy Astrophysical Phenomena |
| الوصف: | We present a comprehensive analysis of the photometric and spectroscopic evolution of SN~2021foa, unique among the class of transitional supernovae for repeatedly changing its spectroscopic appearance from hydrogen-to-helium-to-hydrogen-dominated (IIn-to-Ibn-to-IIn) within 50 days past peak brightness. The spectra exhibit multiple narrow ($\approx$ 300--600~km~s$^{-1}$) absorption lines of hydrogen, helium, calcium and iron together with broad helium emission lines with a full-width-at-half-maximum (FWHM) of $\sim 6000$~km~s$^{-1}$. For a steady, wind-mass loss regime, light curve modeling results in an ejecta mass of $\sim 8$ M$_{\odot}$ and CSM mass below 1 M$_{\odot}$, and an ejecta velocity consistent with the FWHM of the broad helium lines. We obtain a mass-loss rate of $\approx 2$ M$_{\odot} {\rm yr}^{-1}$. This mass-loss rate is three orders of magnitude larger than derived for normal Type II SNe. We estimate that the bulk of the CSM of SN~2021foa must have been expelled within half a year, about 15 years ago. Our analysis suggests that SN~2021foa had a helium rich ejecta which swept up a dense shell of hydrogen rich CSM shortly after explosion. At about 60 days past peak brightness, the photosphere recedes through the dense ejecta-CSM region, occulting much of the red-shifted emission of the hydrogen and helium lines, which results in observed blue-shift ($\sim -3000$~km~s$^{-1}$). Strong mass loss activity prior to explosion, such as those seen in SN~2009ip-like objects and SN~2021foa as precursor emission, are the likely origin of a complex, multiple-shell CSM close to the progenitor star. Comment: Submitted to ApJ, 21 figures, 7 tables |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2409.01359 |
| رقم الأكسشن: | edsarx.2409.01359 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |