论文标题
ETA Carinae在2020年X射线最低的X射线特性
The X-ray properties of Eta Carinae during its 2020 X-ray minimum
论文作者
论文摘要
巨大的二元系统ETA Carinae的特征是强烈的碰撞风，形成冲击并发出X射线。该系统高度偏心（$ e \ simeq0.9 $），导致其在5.54年轨道上进行了调制的X射线排放。 X射线通量在Periastron通道前的几个月内增加，表现出强烈的耀斑，然后迅速下降至持续数周的平坦，然后逐渐恢复。我们提出了中性星的内部组成探索器（较好的）望远镜光谱，在2020 X射线最小值之前，之中和之后获得，并执行光谱分析以建立X射线通量和X射线磁通柱密度的时间行为（$ n _ {\ n _ {\ rm H}（\ rm H}（T）$ 2-10 kev和5-10 kev和5-10 kev和5-10 kev。后一个范围由恒星风碰撞区域主导，因此，这些光谱参数（尤其是$ n _ {\ rm h}（t）$）是对二进制方向的潜在严格约束。我们将观察到的$ n _ {\ rm h}（t）$结果比较了一个简单的几何模型所预测的行为，以尝试确定Periastron的哪个星与我们更接近我们：较大的主要（$ω\ simeq 240 $ - $ 270^\ circe）我们发现，柱密度的变化远非植物和周围的Periastron段落，支持后一种配置（$ω\ simeq 90^\ circ $）。 2020 X射线最小值显示了最近五个最小值的恢复最快，这为最近的主要恒星风减弱提供了更多证据。
The massive binary system Eta Carinae is characterized by intense colliding winds that form shocks and emit X-rays. The system is highly eccentric ($e\simeq0.9$), resulting in modulated X-ray emission during its 5.54 year orbit. The X-ray flux increases in the months prior to periastron passage, exhibiting strong flares, then rapidly declines to a flat minimum lasting a few weeks, followed by a gradual recovery. We present Neutron Star Interior Composition Explorer (NICER) telescope spectra obtained before, during, and after the 2020 X-ray minimum, and perform spectral analysis to establish the temporal behavior of X-ray flux and X-ray-absorbing column density ($N_{\rm H}(t)$) for the 2-10 keV and 5-10 keV energy ranges. The latter range is dominated by the stellar wind collision region and, therefore, these spectral parameters - in particular, $N_{\rm H}(t)$ - serves as a potentially stringent constraint on the binary orientation. We compare the observed $N_{\rm H}(t)$ results to the behavior predicted by a simple geometrical model in an attempt to ascertain which star is closer to us at periastron: the more massive primary ($ω\simeq 240$-$270^\circ$), or the secondary ($ω\simeq 90^\circ$). We find that the variations in column density, both far from periastron and around periastron passage, support the latter configuration ($ω\simeq 90^\circ$). The 2020 X-ray minimum showed the fastest recovery among the last five minima, providing additional evidence for a recent weakening of the primary star's wind.
