文章基本信息

标题：Spectral signatures of H-rich material stripped from a non-degenerate companion by a Type Ia supernova
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作者：Luc Dessart ; Douglas C. Leonard ; Jose L. Prieto 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2020
卷号：638
页码：1-17
DOI：10.1051/0004-6361/202037854
语种：English
出版社：EDP Sciences
摘要：The single-degenerate scenario for Type Ia supernovae should yield metal-rich ejecta that enclose some stripped material from the non-degenerate H-rich companion star. We present a large grid of non-local thermodynamic equilibrium steady-state radiative transfer calculations for such hybrid ejecta and provide analytical fits for the Hαluminosity and equivalent width. Our set of models covers a range of masses for56Ni and the ejecta, for the stripped material (Mst), and post-explosion epochs from 100 to 300 d. The brightness contrast between stripped material and metal-rich ejecta challenges the detection of H Iand He Ilines prior to ~100 d. Intrinsic and extrinsic optical depth effects also influence the radiation emanating from the stripped material. This inner denser region is marginally thick in the continuum and optically thick in all Balmer lines. The overlying metal-rich ejecta blanket the inner regions, completely below about 5000 Å, and more sparsely at longer wavelengths. As a consequence, Hβshould not be observed for all values ofMstup to at least 300 days, while Hαshould be observed after ~100 d for allMst≥ 0.01M⊙. Observational non-detections capable of limiting the Hαequivalent width to <1 Å set a formal upper limit ofMst< 0.001M⊙. This contrasts with the case of circumstellar-material (CSM) interaction, not subject to external blanketing, which should produce Hαand Hβlines with a strength dependent primarily on CSM density. We confirm previous analyses that suggest low values of order 0.001M⊙forMstto explain the observations of the two Type Ia supernovae with nebular-phase Hαdetection, in conflict with the much greater stripped mass predicted by hydrodynamical simulations for the single-degenerate scenario. A more likely solution is the double-degenerate scenario, together with CSM interaction, or enclosed material from a tertiary star in a triple system or from a giant planet.
关键词：Key wordsenradiative transfersupernovae: general