暗彗星 1998 KY$_{26}$ 的火卫一（Phobos 1）假说可行性研究

中文摘要 AI 辅助

小行星 1998 KY$_{26}$ 自 1998 年 5 月 28 日被发现后不久，直至 2020 年和 2024 年的两次近距离回归，一直受到光学和雷达的深入观测。此前的研究已对该天体进行了精确表征，包括周期为 5.3516 $\pm$ 0.0001 分钟的异常快速自转、直径 11 $\pm$ 2 米以及约 0.52 的高反照率。此外，在未探测到明显气体或尘埃抛射的情况下，存在显著的非引力加速度（NGAs），这促成了其“暗彗星”的分类，日本宇宙航空研究开发机构（JAXA）已重新调整其隼鸟2号$\sharp$（Hayabusa2$\sharp$）航天器任务，计划于 2031 年与目标交会。我们追踪了指向该天体可能实际上是失踪的苏联火卫一（Phobos 1）探测器的天体动力学证据，并分析了与 1998 KY$_{26}$ 相关的各种测光和天体测量数据，以进一步研究该假说的可行性。我们发现，火卫一航天器的一阶近似模型与目标的 8 条光变曲线高度吻合；此外，将非引力加速度建模为圆柱体或太阳能电池板上的太阳辐射压（SRP），可使 260 个天体测量和雷达测量数据的残差显著降低约 11%。尽管此类研究无法得出最终结论，但我们的结果有力支持了火卫一假说，且未发现明显的矛盾证据。基于火卫一假说，由测光计算得到的黄道 J2000 坐标系中的自转极轴为 $(\lambda,\beta)=({151^{+1}_{-2}}^{\circ},{+11^{+12}_{- 3}}^{\circ})$，其中所列范围代表约 68.3% 的置信水平。

英文摘要

The asteroid 1998 KY$_{26}$ has been the subject of thorough observation, both optical and radar, from shortly following its discovery on 28 May 1998, through 2 further close apparitions in 2020 and 2024. This has previously allowed an accurate characterization of the object, including an unusually rapid spin-rate with period 5.3516 $\pm$ 0.0001 minutes, a diameter of 11 $\pm$ 2 m, and a high albedo of $\sim{0.52}$. Furthermore, the presence of significant nongravitational accelerations (NGAs), with no detectable shedding of gas or dust, has stimulated the 'dark comet' categorization, with JAXA repurposing their Hayabusa2$\sharp$ spacecraft to rendezvous with the object in 2031. We follow-up the astrodynamical evidence pointing to the possibility this may actually be the lost Soviet Phobos 1 probe, and analyse various photometry and astrometry associated with 1998 KY$_{26}$ to further investigate the feasibility of this hypothesis. We find a first order approximation of the Phobos 1 spacecraft provides compelling agreement to 8 light curves of the object and further that modelling NGAs as solar radiation pressure (SRP) on a cylinder or solar panels provide significant reductions in residual of $\sim{11} \%$ with respect to the 260 astrometric and radar measurements. Although an investigation of this kind cannot be conclusive, nevertheless the results here add strong weight to the Phobos 1 hypothesis, and we find no clear contradictory evidence. The spin pole in Ecliptic J2000 coordinates, calculated from photometry based on the Phobos 1 assumption is $(λ,β)=({151^{+1}_{-2}}^{\circ},{+11^{+12}_{- 3}}^{\circ})$ , where the quoted ranges represent approximate 68.3\% confidence levels.

发表机构

• Initiative for Interstellar Studies（星际研究倡议）

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