论文标题
带有狼射线型中心星的行星星云 - iv。 NGC 1501及其混合层
Planetary nebulae with Wolf-Rayet-type central stars -- IV. NGC 1501 and its mixing layer
论文作者
论文摘要
理论预测，X射线发射气体的温度（$ \ sim $ 10 $^{6} $ k）从行星nebulae（PNE）中检测到的温度是与离子化的外部边缘接触时混合或热传导的结果（$ \ sim $ \ sim $ 10 $^{4} $ k）。通过C IV，N V和O VI离子，可以使用中等温度的气体（$ \ sim $ 10 $^{5} $ K）来研究X射线发射气体的物理。在这里，我们对NGC 1501的CSPN的出色气氛进行建模，以证明即使是这种热的H缺陷型[WO4]型恒星也无法通过光电离来产生这些发射线。我们使用C IV系的检测来评估该pne中混合区域的物理性质，并与其X射线发射气体相比，使NGC 1501仅具有具有这种表征的第二个PNE。我们将预测扩展到最热的[WO1]和冷却器[WC5]类型的类型，并证明大多数能量的光子都被[WR] CSPN的密集风吸收，并且高度离子化的物种可用于研究PNE中热气泡产生的物理。我们发现NGC 2452，NGC 6751和NGC 6905的UV观测与存在的混合层和热气泡一致，为将来的X射线观测提供了出色的候选者。
Theory predicts that the temperature of the X-ray-emitting gas ($\sim$10$^{6}$ K) detected from planetary nebulae (PNe) is a consequence of mixing or thermal conduction when in contact with the ionized outer rim ($\sim$10$^{4}$ K). Gas at intermediate temperatures ($\sim$10$^{5}$ K) can be used to study the physics of the production of X-ray-emitting gas, via C IV, N V and O VI ions. Here we model the stellar atmosphere of the CSPN of NGC 1501 to demonstrate that even this hot H-deficient [WO4]-type star cannot produce these emission lines by photoionization. We use the detection of the C IV lines to assess the physical properties of the mixing region in this PNe in comparison with its X-ray-emitting gas, rendering NGC 1501 only the second PNe with such characterization. We extend our predictions to the hottest [WO1] and cooler [WC5] spectral types and demonstrate that most energetic photons are absorbed in the dense winds of [WR] CSPN and highly ionized species can be used to study the physics behind the production of hot bubbles in PNe. We found that the UV observations of NGC 2452, NGC 6751 and NGC 6905 are consistent with the presence mixing layers and hot bubbles, providing excellent candidates for future X-ray observations.
