论文标题
XMM-Newton和高度可变的Polar V496 UMA的苔丝观察
XMM-Newton and TESS observations of the highly variable polar V496 UMa
论文作者
论文摘要
我们旨在研究\ vum从光学到X射线态的时间和光谱行为。我们使用了2017年和2019年获得的档案\ XMMN和\ tes观测值来对高度可变的极性进行光谱和时机分析。两颗卫星（苔丝）和XMM-Newton的光曲线揭示了一个双重插入图案，该图案调制了$ 91.058467 \ pm 0.00001 $分钟。 V496 UMA以高积聚状态显示两极增生的几何形状。来自两个区域的X射线光谱由热等离子体辐射和柔软的黑体组成组成，其温度几乎相同，总积聚速率为$ \ dot {m} = 1.4（8）\ times10^{ - 11}} $ _ {\ odot} $ _ {\ odot} $ yr yr $^{ - yr $^{ - 1} $。驼峰的X射线中心分别显示-18和4度的纵向移位，-172和-186度的大小分别在光度相位零附近，分别为主驼峰和第二个驼峰。长期的ZTF光曲线显示出高和低积聚状态。低状态的ZTF和SDSS光度数据与10000 K时的0.8 $ m $ _ {\ odot} $白色矮人和一个主序列供体星，在758 pc的\ gai-de-de-de-de-de-de-dections pc。 V496 UMA在X射线中处于高状态时是非常明亮的极性。由于其异常的几何结构，偶尔会中断到第二个积聚极上的质量积聚。这种不连续的行为在时间上没有遵循某种模式，并且仅在高状态下才观察到。 X射线光曲线在$ ϕ = $ 0.81的光度阶段显示出积分流的明确证据，在光光曲线中不会显示。使用组合的苔丝和XMM-Newton数据得出了一个准确的时期，该数据与已发布的结果不同。
We aim to study the temporal and spectral behaviour of \vum from the optical to the X-ray regimes. We used archival \xmmn and \tes observations obtained in 2017 and 2019 to perform a spectral and timing analysis of the highly variable polar. The light curves of both satellites, TESS and XMM-Newton, reveal a double-humped pattern modulated with the periodicity of $91.058467 \pm 0.00001$ minutes. V496 UMa displays a two-pole accretion geometry in the high accretion state. X-ray spectra from both regions are composed of thermal plasma radiation and soft blackbody components with almost identical temperatures and a total accretion rate of $\dot{M}=1.4(8)\times10^{-11}$ M$_{\odot}$ yr$^{-1}$. The X-ray centers of the humps show longitudinal shifts of -18 and 4 degrees and -172 and -186 degrees size around photometric phase zero, for the main hump and second hump, respectively. The long-term ZTF light curves reveal high and low accretions states. Low-state ZTF and SDSS photometric data are consistent with an $0.8$ M$_{\odot}$ white dwarf at 10000 K and a main-sequence donor star with a spectral type of M5.0 at a \gai-determined distance of 758 pc. V496 UMa is a very bright polar in X-rays when it is in the high state. Due to its unusual geometric structure, mass accretion onto the second accretion pole is interrupted occasionally. This discontinuous behavior does not follow a certain pattern in time and is observed so far only in the high state. The X-ray light curves display clear evidence for an accretion stream at the photometric phase of $ϕ=$0.81, which does not show up in optical light curves. An accurate period was derived using the combined TESS and XMM-Newton data, which differs by 3.8 $σ$ from published results.
