PIA11404: Magnetometer Results from MESSENGER's Second Mercury Encounter
Target Name: Mercury
Is a satellite of: Sol (our sun)
Mission: MESSENGER
Spacecraft: MESSENGER
Instrument: Magnetometer
Product Size: 720 x 978 pixels (width x height)
Produced By: Johns Hopkins University/APL
Full-Res TIFF: PIA11404.tif (2.115 MB)
Full-Res JPEG: PIA11404.jpg (62.98 kB)

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Original Caption Released with Image:

The top figure shows a view of Mercury from above its north pole and the trajectories along which Magnetometer observations were made by the Mariner 10 mission (blue) and the MESSENGER spacecraft (tan). The MESSENGER data from the missionís second Mercury flyby provide the only data to date from the planetís western hemisphere and are therefore key to constraining the geometry of the planetís internal magnetic field. The bottom figure graphs the magnetic field strengths measured during MESSENGERís first (blue) and second (orange) Mercury flybys, with a striking similarity in the maximum field strength measured during both encounters. The observations are displayed versus distance along the planet-Sun line; closest approach (CA) occurred at about three-fourths of a Mercury radius to the night side of the planet. The magnetopause and bow shock crossings occurred where they were expected, so for this comparison the distance scale for flyby 1 has been stretched so that these boundaries are coincident. Near CA, the flyby 2 data yield a field strength that is only a few percent lower than that obtained from flyby 1 observations. This remarkably close agreement means that the planetary magnetic moment is very nearly centered and is strongly aligned with the rotation axis, to within a tilt of 2į. This result favors models for Mercuryís magnetic field generation that predict a magnetic moment aligned with the rotation axis.

Date Acquired: January 14 and October 6, 2008
Instrument: Magnetometer (MAG)

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.

Image Credit:
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Image Addition Date:
2008-10-29