Geodetic Evidence That Mercury Has A Solid Inner Core

Geodetic analysis of radio tracking measurements of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging 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 (α = 281.0...

Full description

Saved in:
Bibliographic Details
Published in:Geophysical research letters 2019-04, Vol.46 (7), p.3625-3633
Main Authors: 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.
Format: Article
Language:English
Subjects:
Aerospace environments
Computer simulation
Declination
Geochemistry
Gravitational fields
Gravity
Gravity field
Inertia
Love number
Markov analysis
Markov chains
Mercury
Mercury (planet)
Mercury surface
MESSENGER Mission
Moments of inertia
Monte Carlo simulation
Obliquity
orientation
Planets
radio science
Radio tracking
solid inner core
Spacecraft
Spacecraft tracking
Statistical methods
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Geodetic analysis of radio tracking measurements of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging 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 (α = 281.0082° ± 0.0009°; all uncertainties are 3 standard deviations) and declination (δ = 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 ϵ 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 (ric) between 0.3 and 0.7 that of the outer core (roc). Key Points New solution for Mercury's gravity field provides crucial information on the planet's tidal response and orientation New determination of Mercury's pole position fully satisfies the equilibrium Cassini state New estimate of Mercury's polar moment of inertia supports the presence of a large solid inner core
ISSN:0094-8276
1944-8007
DOI:10.1029/2018GL081135