Different environments in the Solar System and their characteristics related to planetary space weather. In order to characterize the effects of solar emissions and winds on different bodies, we consider the existence of ionosphere (I), magnetosphere (M), exosphere (E). The interplanetary (or planetary) magnetic field inclination, given in the Table’s last column, is measured with respect to the body’s spin axis; the estimations of the IMF inclination are based on the Parker model, for an average solar wind velocity equal to 450 km/s.
|Solar system body||Distance from the Sun (in AU)||Body’s radius (in km)||Rotation period (in hours)||Planetary space weather regions||Atmosphere major composition||Magnetic field morphology||Solar wind density (in cm−3)||Interplanetary magnetic field
|Intensity (nT)||Inclination (in deg)|
|Neptune||30.071||24,7641||16.111||I, M, E||H2, He, CH4 1||Dipole||0.00815||0.1122||88.1|
|Uranus||191||25,5591||17.241||I, M, E||H2, He, CH4 1||Multipole||0.0215||0.2223||87.0|
|Saturn||9.51||60,3301||10.6561||I, M, E||H2, He1||Dipole||0.115||0.2–0.824||83.9|
|Jupiter||5.21||71,3981||9.9251||I, M, E||H2, He1||Dipole||0.315||0.5–1.2125||79.0|
|Mars||1.5241||3,3901||24.6231||I, E||CO2, N2 1||Crustal fields||3.515||2–326||56.4|
|Venus||0.7231||6,0511||5,832.61||I, E||CO2, N2 1||Induced||1615||1227||35.5|
|Mercury||0.31–0.471||2,4391||1,407.61||M, E||Exosphere: Na, K, Mg, Ca, H, He, Al1||Dipole||32–7316||15–3028||21.1|
|Solar system body||Distance from the parent planet (in planet radii)||Body’s radius (in km)||Rotation period (in Earth days)||Planetary space weather regions||Major composition of the neutral environment||Magnetic field morphology||Magnetospheric plasma density (in cm−3)||Planet’s magnetic field at the satellite’s distance
|Direction and intensity (nT)||Inclination|
|Jupiter's satellites||Io||5.912||1,821.62||S 1.772||E||Exosphere: SO2 4||–||1,920 (ions) 2,500 (electrons)17||−1,90029||32 , 33|
|Europa||9.402||1,560.82||S 3.552||E||Exosphere: O2, H2O gas plume5||Induced12||8.8–40.6 (S2+) 5–23.2 (O2+) 7.6–34.8 (H+) 63 –290 (electrons)18||−42029||32 , 33|
|Ganymede||14.972||2,631.22||S 7.152||M, E||Exosphere: O2, H6||Intrinsic dipole and induced13||1–8 (ions) 1–10 (electrons)17||−9029||32 , 33|
|Callisto||26.332||2,410.12||S 16.692||E||Exosphere: CO2, O2 7||Induced12||0.10 (ions) 0.15 (electrons)17||−3029||32 , 33|
|Saturn's satellites||Enceladus||3.953||257 × 251 × 2483||S 1.373||E||Exosphere (gas plume): H2O, CO2, Mass 28 (CO or N2), CH4 8||?14||40 (electrons) 4–40 (ions)19||−37030||32 , 34|
|Dione||6.263||563 × 561 × 5603||S 2.743||E||Exosphere: O2, CO2 9||?14||13 (electrons) 2–20 (ions)19||−7530||32 , 34|
|Rhea||8.743||765 × 763 × 7623||S 4.523||E||Exosphere: CO2, O2 10||?14||2 (electrons) 0.4–3 (ions)19||−2530||32 , 34|
|Titan||20.273||2,5753||S 15.953||I, E||Atmosphere: N2, CH4 11||Induced14||30–1,000 (electrons)20 20–2,000 (ions)21||−5.131||32 , 34|
As reported in NASA Planetary Fact Sheet http://nssdc.gsfc.nasa.gov/planetary/factsheet/
From the NASA Jovian Satellite Fact Sheet http://nssdc.gsfc.nasa.gov/planetary/factsheet/joviansatfact.html; Note that S stands for synchronous rotation.
From the NASA Saturnian Satellite Fact Sheet http://nssdc.gsfc.nasa.gov/planetary/factsheet/saturniansatfact.html; Note that S stands for synchronous rotation.
As reported in Lopes & Williams (2005).
For observations interpreted as indicative for an O2 atmosphere see Hall et al. (1995, 1998), Saur et al. (2011) and McGrath et al. (2004). Observations interpreted as indicative for a transient water plume were discussed in Roth et al. (2014a).
See Hall et al. (1998), Feldman et al. (2000), Barth et al. (1997).
See Waite et al. (2006).
See Teolis et al. (2010).
For Europa see Khurana et al. (1998, 2009). For Callisto see Khurana et al. (1998).
It is currently not known if induced magnetic fields are generated at the inner Saturnian moons. Titan’s ionosphere, being subject to direct erosion by the incident plasma ﬂow, generates an induced magnetosphere around the moon: the ambient magnetospheric ﬁeld drapes around Titan’ s ionosphere, leading to the formation of a magnetic pile-up region at the ramside and a bipolar magnetotail in the wake region (see Simon et al. 2013b for details).
As reported in Richardson et al. (2004).
As reported in Milillo et al. (2005).
As reported in Kivelson et al. (2004, Table 21.1).
For a detailed description of the plasma environment at Europa see Bagenal et al. (2015) and Delamere et al. (2005).
See Edberg et al. (2010).
See Mandt et al. (2012).
See Voigt et al. (1983).
See Jackman et al. (2004). These values were measured by Cassini in 2004 and correspond to magnetopause crossings.
Ulysses data (1992, 1998, 2004) and Cassini data (2000) taken from Table 1 in Nichols et al. (2006).
Estimation based on the analysis of Mars Global Surveyor (MGS) Magnetometer (MAG) data from the region upstream from Mars (Brain et al. 2003). The spiral angle was found in the range 32°–70°.
See Figure 5 in Baker et al. (2013). CME passages (with stronger magnetic fields in and draped around the CMEs) and other transient solar wind can result in IMF enhancements (Baker et al. 2013).
Since neither the orbits nor the spin axes of the moons are significantly inclined to the parent planet’s equatorial plane, we present here the averages around the moon’s orbit as reported in Kivelson & Bagenal (2007). The minus sign indicates that the average field over a planetary rotation period is southward oriented, i.e. antiparallel to the planet’s rotation axis.
The magnetic fields of Jupiter and Saturn at the orbits of their moons oscillate in intensity and direction at the giant planets rotation periods, equal to 9.925 h and 10.656 h, respectively.
The average field over a planetary rotation period is southward oriented, i.e. antiparallel to Jupiter’s axis of rotation (Kivelson & Bagenal 2007). The spin axes of the moons are not significantly inclined to the parent planet’s equatorial plane: 0.04° (Io); 0.47° (Europa); 0.21° (Ganymede); 0.51° (Callisto), according to http://nssdc.gsfc.nasa.gov/planetary/factsheet/joviansatfact.html. Therefore the inclination of the parent planet’s magnetic field (with respect to the satellite’s spin axis) is negligible.
As in the Jupiter’s case, the spin axes of the moons are not significantly inclined to the parent planet’s equatorial plane: 0.00° (Enceladus); 0.02° (Dione); 0.35° (Rhea); 0.33° (Titan), according to http://nssdc.gsfc.nasa.gov/planetary/factsheet/saturniansatfact.html. Therefore the inclination of the parent planet’s magnetic field (with respect to the satellite’s spin axis) is negligible.
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