论文标题
使用加拿大自动流星天文台进行高精度的流星观测 - 数据减少管道和对流星机械强度测量的应用
High precision meteor observations with the Canadian Automated Meteor Observatory -- Data reduction pipeline and application to meteoroid mechanical strength measurements
论文作者
论文摘要
语境。加拿大自动流星天文台（CAMO）的镜像跟踪系统可以实时跟踪流星，提供1弧秒的有效角度分辨率，每秒的时间分辨率为100帧。 目标。我们描述了升级的硬件，并提供数据校准和减少管道的详细信息。我们研究了流星形态对辐射和速度测量精度的影响，并使用对流星碎片化的直接观察来限制其抗压强度。 方法。 2017年7月21日，Camo在JFC轨道上观察到一个约4秒的流星。它具有较浅的入口角度〜8度，在窄场视频中可以看到12个片段。该事件是手动减少的，并确定了碎片的确切力矩。碎裂时刻的空气动力RAM压力被用作抗压强度的代理，并以相同的方式测量了另外19个碎片灭绝体体的强度。使用Navgem-HA数据估计大气中的质量密度的不确定性为+/- 25％。 结果。我们发现流星轨迹准确性显着取决于流星形态。短尾流的非碎片流星的迷彩辐射和初始速度精度为〜0.5'和1 m/s，而对于具有碎片或长尾流的流星的流星，类似于非跟踪，中等中度的视野光学磁场（5'，5'，〜50 m/s）。 20个碎片的酿酒素的测量抗压强度（由于其形态而导致的辐射较少）在1-4 kPa的范围内，这与Rosetta的67p的耐用性测量值非常相符。碎裂类型和强度似乎并不取决于轨道。 7月21日的麦克体中的12个片段的质量指数非常高（s = 2.8），表明可能进行性碎裂。
Context. The mirror tracking system of the Canadian Automated Meteor Observatory (CAMO) can track meteors in real time, providing an effective angular resolution of 1 arc second and a temporal resolution of 100 frames per second. Aims. We describe the upgraded hardware and give details of the data calibration and reduction pipeline. We investigate the influence of meteor morphology on radiant and velocity measurement precision, and use direct observations of meteoroid fragmentation to constrain their compressive strengths. Methods. On July 21, 2017, CAMO observed a ~4 second meteor on a JFC orbit. It had a shallow entry angle ~8 deg and 12 fragments were visible in the narrow-field video. The event was manually reduced and the exact moment of fragmentation was determined. The aerodynamic ram pressure at the moment of fragmentation was used as a proxy for compressive strength, and strengths of an additional 19 fragmenting meteoroids were measured in the same way. The uncertainty in the atmosphere mass density was estimated to be +/-25% using NAVGEM-HA data. Results. We find that meteor trajectory accuracy significantly depends on meteor morphology. The CAMO radiant and initial velocity precision for non-fragmenting meteors with short wakes is ~0.5' and 1 m/s, while that for meteors with fragments or long wakes is similar to non-tracking, moderate field of view optical systems (5', ~50 m/s). Measured compressive strengths of 20 fragmenting meteoroids (with less precise radiants due to their morphology) was in the range of 1-4 kPa, which is in excellent accord with Rosetta in-situ measurements of 67P. Fragmentation type and strength do not appear to be dependent on orbit. The mass index of the 12 fragments in the July 21 meteoroid was very high (s = 2.8), indicating possible progressive fragmentation.
