Deconstructing Photospheric Spectral Lines in Solar and Stellar Flares
Deconstructing Photospheric Spectral Lines in Solar and Stellar Flares
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DOI：
10.3847/1538-4357/ad16da
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发表时间：
2024-01
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影响因子：
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通讯作者：
Aaron Monson;M. Mathioudakis;A. Kowalski
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作者：
Aaron Monson;M. Mathioudakis;A. Kowalski
在太阳耀斑期间，在光球层中形成的光谱线已经显示出其轮廓的变化，尽管能量转移到这些深度的挑战。最近的工作表明，在整个耀斑期间，深层形成的光谱线受到光球层以上区域的显著贡献，从而导致大气层多层的复合出射强度分布。我们采用辐射流体动力学和辐射传输计算模拟太阳/恒星大气的响应，电子束加热和合成的Fe i的光谱线调查的视线速度场的信息，从多普勒频移的出射强度分布。通过利用贡献函数解构线轮廓形状到其组成来源，我们表明，线轮廓的变化主要是由色球层的变化引起的。在这个区域的上升流被发现创建蓝移或假红移线核心依赖于色球层的相对贡献相比，光球。在极端的太阳和恒星耀斑的情况下，具有爆炸性的色球凝聚，红移瞬态分量可以主导的轮廓形状的时间演变，需要一个第三分量的考虑，以充分表征。我们的结论是，深形成线需要多方面的理解和治疗，不同地区的光谱线是有用的探测个别地区的大气的速度流。
During solar flares, spectral lines formed in the photosphere have been shown to exhibit changes to their profiles despite the challenges of energy transfer to these depths. Recent work has shown that deep-forming spectral lines are subject to significant contributions from regions above the photosphere throughout the flaring period, resulting in a composite emergent intensity profile from multiple layers of the atmosphere. We employ radiative–hydrodynamic and radiative transfer calculations to simulate the response of the solar/stellar atmosphere to electron beam heating and synthesize spectral lines of Fe i to investigate the line-of-sight velocity fields information available from Doppler shifts of the emergent intensity profile. By utilizing the contribution function to deconstruct the line profile shape into its constituent sources, we show that variations in the line profiles are primarily caused by changes in the chromosphere. Up-flows in this region were found to create blueshifts or false redshifts in the line core dependent on the relative contribution of the chromosphere compared to the photosphere. In extreme solar and stellar flare scenarios featuring explosive chromospheric condensations, redshifted transient components can dominate the temporal evolution of the profile shape, requiring a tertiary component consideration to fully characterize. We conclude that deep-forming lines require a multicomponent understanding and treatment, with different regions of the spectral line being useful for probing individual regions of the atmosphere’s velocity flows.