摘要:
重迭在船帆座超新星遗骸(Vela supernova remnant)视线上的ROSAT X射线源RX J0852.0-4622，或称Vela Jr.，因其在1.3千电子伏的波段上呈现圆壳外观和检测出44Ti的γ射线衰变线，所以被认为是新发现的年轻超新星遗骸。然而，观测证据指出Vela Jr.应属于船帆座超新星遗骸的一部份而非独立的物体。二维气体动力学模拟显示，超新星快速的高密度喷发气体物(子弹)可以影响遗骸的外围，产生类似于Vela Jr.的圆环结构。估计Vela Jr.的能量为<0.3 × 1049 erg，相当于1700 km/s、<~0.1M⊙的超新星喷发物所注入的动能。我们认为子弹生成最有可能的机制是镍泡效应(nickel bubble effect)。我们预测子弹应该产生辐射，而船帆座超新星遗骸在低X射线亮度的波段上也应存在其它类似的结构。
Abstract: The ROSAT source RX J0852.0-4622, or Vela Jr., superposed on the Vela supernova remnant, has been identified as a separate young supernova remnant based on its shell-like appearance in X-ray > 1.3 keV and on its detection as a source of the 44Ti γ-ray decay line. However, a re-examination of the observational facts suggests that Vela Jr. should be part of the Vela remnant. We suggest that the shell X-ray feature is produced by a fast ejecta clump (bullet) from the Vela supernova that deposited its kinetic energy in the supernova remnant shell. The estimated energy < 0.3 × 1049 erg could be supplied by a <~0.1M⊙ clump moving at1700 km/s. Two-dimensional gas dynamic simulations show that a circular appearance can be produced in the supernova shell under proper conditions. We suggest that the nickel bubble effect is responsible for producing such heavy ejecta clumps in supernovae. There may be other similar X-ray features at a lower brightness level and there may be emission from heavy element ejecta in the object.