Genova Antonio, Goossens Sander, Mazarico Erwan, Lemoine Frank G, Neumann Gregory A, Kuang Weijia, Sabaka Terence J, Hauck Steven A, Smith David E, Solomon Sean C, Zuber Maria T
Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology.
NASA Goddard Space Flight Center.
Geophys Res Lett. 2019 Apr 16;46(7):3625-3633. doi: 10.1029/2018GL081135. Epub 2019 Mar 15.
Geodetic analysis of radio tracking measurements of the MESSENGER spacecraft while in orbit about Mercury has yielded new estimates for the planet's gravity field, tidal Love number, and pole coordinates. The derived right ascension ( = 281.0082° ± 0.0009°; all uncertainties are 3 standard deviations) and declination ( =61.4164° ± 0.0003°) of the spin pole place Mercury in the Cassini state. Confirmation of the equilibrium state with an estimated mean (whole-planet) obliquity of 1.968 ± 0.027 arcmin enables the confident determination of the planet's normalized polar moment of inertia (0.333 ± 0.005), which indicates a high degree of internal differentiation. Internal structure models generated by a Markov-Chain Monte Carlo process and consistent with the geodetic constraints possess a solid inner core with a radius ( ) between 0.3 and 0.7 that of the outer core ( ).
信使号航天器在绕水星轨道运行时进行的无线电跟踪测量的大地测量分析，得出了该行星引力场、潮汐勒夫数和极坐标的新估计值。推导得出的自转轴赤经（=281.0082°±0.0009°；所有不确定性均为3倍标准差）和赤纬（=61.4164°±0.0003°）使水星处于卡西尼状态。对平衡状态的确认，其估计的平均（全行星）倾角为1.968±0.027角分，使得能够可靠地确定该行星的归一化极转动惯量（0.333±0.005），这表明其内部存在高度分化。通过马尔可夫链蒙特卡罗过程生成并与大地测量约束条件一致的内部结构模型，拥有一个固态内核，其半径（ ）在外核（ ）半径的0.3至0.7之间。
