I pinpoint a previously unrecognized MOND effect that may act in the inner solar system, and is due to the galactic acceleration, g_g=eta*a0: a byproduct of the MOND external-field effect. Predictions of the effect are not generic to the MOND paradigm, but depend on the particular MOND formulation at hand. However, the modified-Poisson formulation, on which I concentrate, uniquely predicts a subtle anomaly that may be detected in planetary and spacecraft motions (and perhaps in other precision systems, such as binary pulsars), despite their very high accelerations, and even if the MOND interpolating function is arbitrarily close to unity at high accelerations. Near the sun, this anomaly appears as a quadrupole field, with the acceleration at position u from the sun being g_i(u)=-q_{ij}u^j, with q_{ij} diagonal, axisymmetric, and traceless: -2q_{xx}=-2q_{yy}=q_{zz}=q(eta)*(a0/R_M), where R_M=(MG/a0)^{1/2}=8*10^3 au is the MOND radius of the sun. The anomaly is described and analyzed as the Newtonian field of the fictitious cloud of ``phantom matter'' that hovers around the sun. I find, for the relevant range of eta values, and for a range of interpolating functions, mu(x), values of 10^{-2}<-q< 0.3, which turn out to be sensitive to the form of mu(x) around the MOND-to-Newtonian transition. This range verges on the present bounds from solar system measurements. There might thus exist favorable prospects for either measuring the effect, or constraining the theory and the relevant parameters.
On the MOND External Field Effect in the Solar System
在修正的牛顿动力学(MOND)框架下,嵌入较大引力系统S中的引力系统s的内部动力学受到S的外部背景场E的影响,即使它是恒定的和均匀的,这意味着违反强等效原理:这就是所谓的外部场效应(EFE)。在太阳系中,由于它在银河系中的运动,E为A_cen \approx 10^-10 m s^-2:它比行星的主要牛顿动量项小几个数量级。在这里,我们纯粹以现象学的方式解决以下问题:太阳的行星是否受到10^-10 m s^-2的EFE的影响?是否可以假定,由于其规模相对较小,其影响对它们来说可以忽略不计?$\bds E$在典型的太阳系行星轨道周期上的恒定性是否会导致净轨道效应消失?事实证明,恒定和均匀的加速度,微扰处理,不诱导非零的长周期轨道上的近心经度的测试粒子的影响。对于E \approx为10^-10 m s^-2的太阳系内行星,它们比E. V. Pitjeva最近利用太阳系重心坐标系中的天文历表获得的非标准近日点岁差的上界大4-6个数量级。E分量的上限为E_x <= 1 x 10^-15 m s^-2,E_y <= 2 x 10^-16 m s^-2,E_z <= 3 x 10^-14 m s^-2。这一结果与MOND对强等价原理的违背是一致的。
The imprint of the MOND external field effect on the Oort cloud comets aphelia distribution
Milgromian动力学(MD或MOND)是一种很有前途的物理描述,特别是在星系中。当被表述为修正的引力理论时,它导致了所谓的外场效应(EFE)。在太阳系中,这意味着绕太阳运行的天体除了潮汐效应外,还受到星系外部引力场的影响,其大小为$\sim2\times10^{-10}$ m s $^{-2}$,方向随时间变化。中间的外奥尔特云(OC)彗星($30<X<60,~X\equiv 10^{6}/a[\text{au}]$,其中$a$是半长轴)在天球上分布不均匀,显示出一个以银河系彗星$L=-45$和135度为中心的大圆周围的明显集中。这种不均匀性超出了彗星、恒星相遇和银河潮汐的经典注入者,以及预期的观测偏差。我们研究了一个假设,即远日点的大圆浓度是MD框架中EFE长期作用的结果。我们认为完全准线性MOND(QUMOND)理论。我们建立了我们的模型,在MD的OC上的分析近似的一个点质量在占主导地位的恒定幅度的外部场的QUMOND潜力。该模型适用于日心距$r\gtrsim10~000$ au。考虑到了卡西尼号无线电跟踪数据分析发现的EFE强度的限制。我们证明了EFE的特征印记的候选人外OC彗星远日点的分布迁移到$r=10~000$ au。通过分析和数值计算,我们表明,EFE和银河潮汐的综合效应可以定性地解释所观察到的外OC彗星远日点分布的特征。