Jovian Systems

Since we have used different Jovian coordinate systems in previous work (Krupp et al., 1993) we include a description of these systems. Most of these systems are discussed in Dessler (1983). The Jovian pole of rotation is defined by the values $(\alpha,\delta)$ given for "Jupiter III" in Table.6. The transformation from $GEI_{J2000}$ can be calculated from

$$T(GEI_{J2000},JUP_X) = E(\alpha+90^\circ,90^\circ-\delta,w_0)$$ (38)

where the prime meridian angle $w_0$ is given in the following table. Note that longitudes are counted left-handed (clockwise) from the prime meridian in the following Jovian systems.

• System I $JUP_I$, mean atmospheric equatorial rotation [S. Table 15.7]
  +Z-axis: Pole of rotation. p-angle: $w_{0I} = 67^\circ.1 +877^\circ.900 d_0$
• System II $JUP_{II}$, mean atmospheric polar rotation [S. Table 15.7]
  +Z-axis: Pole of rotation. p-angle: $w_{0II} =43^\circ.3+870^\circ.270 d_0$
• System III $JUP_{III}$, magnetospheric rotation [S. Table 15.7]
  

  +Z-axis:	Pole of rotation. p-angle: $w_{0III} = 284^\circ.95+870^\circ.536 d_0$
  Transform:	$T(GEI_{J2000},JUP_{III}) = E(\alpha+90^\circ,90^\circ-\delta,w_{0III})$

  This is the 1965 definition of System III, the Pioneer missions used the 1957 definition:
  

  $$w_{01957} = w_{0III} + 106^\circ.31209 + 0.0083169 d_0$$
  
  
  which can be calculated from eqn.7c in Seidelmann and Divine (1977) and was originally defined by the magnetospheric rotation period.
• System III fix Sun Line
  +Z-axis: Pole of rotation. +Y-axis: cross-product of +Z-axis and vector (Jupiter-Sun)
• Magnetic Dipole System $JUP_D$ (Dessler, 1983)
  +Z-axis:    dipole axis defined by its System III latitude and longitude:
  
  $$lat_D = (90^\circ-9^\circ.8) \hspace{1cm} \lambda_D = 200^\circ$$
  
  

  +X-axis:	intersection of System III prime meridian and magnetic equator.
  Transform:	$T(JUP_{III},JUP_D) = E(\lambda_D+90^\circ,9^\circ.8,-\lambda_D-90^\circ)$ (approximately).

• Centrifugal System $JUP_C$(Dessler, 1983)
  

  +Z-axis:	centrifugal axis defined by its System III latitude and longitude:
  	$lat_C = (90^\circ-7^\circ.0) \hspace{1cm} \lambda_C = 200^\circ$
  +X-axis:	intersection of System III prime meridian and centrifugal equator.
  Transform:	$T(JUP_{III},JUP_C) = E(\lambda_C+90^\circ,7^\circ.0,-\lambda_C-90^\circ)$ (approximately).

• Magnetic Dipole System fix Sun line
  +Z-axis: dipole axis. +Y-axis: cross-product of +Z-axis and vector (Jupiter-Sun)
• Magnetic Dipole $r\theta\phi$ System
  +X-axis: vector (Jupiter-S/C) +Z-axis: (dipole axis)$\times$+X-axis
  This system depends on the S/C-position.