Rotation of Europa: Constraints from Terminator and Limb Positions

Gregory Hoppa, Richard J. Greenberg, Paul Geissler, B. Randall Tufts, J. Plassmann, Daniel D. Durda

Research output: Contribution to journalArticle

26 Scopus citations


Tidal torques on Europa due to Jupiter would tend to drive Europa's rotation to a rate slightly faster than synchronous, unless synchroneity is maintained by a permanent asymmetry in Europa's mass distribution. Moreover, global fracture patterns on Europa's surface, as well as the complex fine-scale tectonics revealed by Galileo high-resolution imagery, may be evidence of stress due to nonsynchronous rotation. A direct measurement of Europa's rotation rate is made from the positions of surface features relative to the terminator in a Galileo image and comparing the results with similar measurements of the positions of the same features relative to the terminator in a Voyager 2 image taken 17 years earlier. Any nonsynchronous rotation must be slower than a few tenths of a degree in 17 years (a complete rotation in >104years) relative to the direction of Jupiter.

Original languageEnglish (US)
Pages (from-to)341-347
Number of pages7
Issue number2
Publication statusPublished - Feb 1 1999



  • Europa
  • Rotation
  • Satellites of Jupiter

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Hoppa, G., Greenberg, R. J., Geissler, P., Tufts, B. R., Plassmann, J., & Durda, D. D. (1999). Rotation of Europa: Constraints from Terminator and Limb Positions. Icarus, 137(2), 341-347.