论文标题
限制1i/2017 U1（`OUMUAMUA）和2i/borisov的旋转轴的方向
Constraining the orientation of the spin axes of extrasolar minor bodies 1I/2017 U1 (`Oumuamua) and 2I/Borisov
论文作者
论文摘要
语境。彗星的旋转轴的方向由其赤道倾斜的值及其彗星的中心经度的值定义。如果彗星活动的表征良好，则可以从由量子造成的nongravitation力的组成部分计算出这些参数。穿过太阳系的已知星体体的轨迹显示了非掠夺加速度。 目标。 1i/2017 U1（`oumuamua）的自旋轴向取向尚待确定；对于2i/borisov，已经发布的结果是互斥的。在这里，我们使用考虑超出味道的公共轨道确定，研究了Oumuamua和2i/Borisov的旋转轴的方向。 方法。我们使用协方差矩阵方法以及蒙特卡洛随机搜索技术应用了蒙特卡洛模拟，以计算赤道倾斜的分布和o oumuamua和2i/borisov的太阳纵向的分布，并从nongravitational parametational parametational parameters of 2i/borisov。 结果。我们发现，如果赤道的赤道倾向，如果它的形状非常宽（梭形），则可能约为93度，如果它非常碎裂，则可能接近16度（类似磁盘样）。 2i/borisov的不同轨道测定的倾斜值为59度和90度。彗星纵向的分布通常是多模式的。 结论。赤道坐标中OUMUAMUA最可能的自旋轴方向是（如果非常宽松，则为280度，+46度），如果非常扁平，则是（312 deg，-50 ver）。对于此处使用的2i/borisov的轨道测定，我们发现最可能的极点指向附近（275度，+65度）和（231度，+30 ver）。尽管我们的分析有利于2i/borisov的扁态形状，但不能排除一个典范的形状。
Context. The orientation of the spin axis of a comet is defined by the values of its equatorial obliquity and its cometocentric longitude of the Sun. These parameters can be computed from the components of the nongravitational force caused by outgassing, if the cometary activity is well characterized. The trajectories of known interstellar bodies passing through the Solar System show nongravitational accelerations. Aims. The spin-axis orientation of 1I/2017 U1 (`Oumuamua) remains to be determined; for 2I/Borisov, the already released results are mutually exclusive. Here, we investigate the orientation of the spin axes of `Oumuamua and 2I/Borisov using public orbit determinations that consider outgassing. Methods. We applied a Monte Carlo simulation using the covariance matrix method together with Monte Carlo random search techniques to compute the distributions of equatorial obliquities and cometocentric longitudes of the Sun at perihelion of `Oumuamua and 2I/Borisov from the values of the nongravitational parameters. Results. We find that the equatorial obliquity of `Oumuamua could be about 93 deg, if it has a very prolate (fusiform) shape, or close to 16 deg, if it is very oblate (disk-like). Different orbit determinations of 2I/Borisov gave obliquity values of 59 deg and 90 deg. The distributions of cometocentric longitudes were in general multimodal. Conclusions. The most probable spin-axis direction of `Oumuamua in equatorial coordinates is (280 degrees, +46 degrees) if very prolate or (312 deg, -50 deg) if very oblate. For the orbit determinations of 2I/Borisov used here, we find most probable poles pointing near (275 deg, +65 deg) and (231 deg, +30 deg), respectively. Although our analysis favors an oblate shape for 2I/Borisov, a prolate one cannot be ruled out.
