# Jupiter mass

Jupiter mass, also called Jovian mass, is the unit of mass equal to the total mass of the planet Jupiter. This value may refer to the mass of the planet alone, or the mass of the entire Jovian system to include the moons of Jupiter. Jupiter is by far the most massive planet in the Solar System. It is approximately 2.5 times as massive as all of the other planets in the Solar System combined.[2]

Jovian Mass
Relative masses of the giant planets of the outer Solar System
General information
Unit systemAstronomical system of units
Unit ofmass
SymbolMJ or MJup, M
Conversions
1 MJ in ...... is equal to ...
SI base unit   (1.89813±0.00019)×1027 kg[1]
U.S. customary   4.1847×1027 pounds

Jupiter mass is a common unit of mass in astronomy that is used to indicate the masses of other similarly-sized objects, including the outer planets and extrasolar planets. It may also be used to describe the masses of brown dwarfs, as this unit provides a convenient scale for comparison.

## Current best estimates

The current best known value for the mass of Jupiter can be expressed as 1898130 yottagrams:

${\displaystyle M_{\mathrm {J} }=(1.89813\pm 0.00019)\times 10^{27}{\text{ kg}},}$ [1]

which is about ​11000 as massive as the sun (is about 0.1% M):

${\displaystyle M_{\mathrm {J} }={\frac {1}{1047.348644\pm 0.000017}}M_{\odot }\approx (9.547919\pm 0.000002)\times 10^{-4}M_{\odot }.}$ [3]

Jupiter is 318 times as massive as Earth:

${\displaystyle M_{\mathrm {J} }=3.1782838\times 10^{2}M_{\oplus }.}$

## Context and implications

Jupiter's mass is 2.5 times that of all the other planets in the Solar System combined—this is so massive that its barycenter with the Sun lies beyond the Sun's surface at 1.068 solar radii from the Sun's center.[4]

Because the mass of Jupiter is so large compared to the other objects in the solar system, the effects of its gravity must be included when calculating satellite trajectories and the precise orbits of other bodies in the solar system, including Earth's moon and even Pluto.

Theoretical models indicate that if Jupiter had much more mass than it does at present, its atmosphere would collapse, and the planet would shrink.[5] For small changes in mass, the radius would not change appreciably, but above about 500 M (1.6 Jupiter masses)[5] the interior would become so much more compressed under the increased pressure that its volume would decrease despite the increasing amount of matter. As a result, Jupiter is thought to have about as large a diameter as a planet of its composition and evolutionary history can achieve.[6] The process of further shrinkage with increasing mass would continue until appreciable stellar ignition was achieved, as in high-mass brown dwarfs having around 50 Jupiter masses.[7] Jupiter would need to be about 75 times as massive to fuse hydrogen and become a star.[8]

## Gravitational constant

The mass of Jupiter is derived from the measured value called the Jovian mass parameter, which is denoted with GMJ. The mass of Jupiter is calculated by dividing GMJ by the constant G. For celestial bodies such as Jupiter, Earth and the Sun, the value of the GM product is known to many orders of magnitude more precisely than either factor independently. The limited precision available for G limits the uncertainty of the derived mass. For this reason, astronomers often prefer to refer to the gravitational parameter, rather than the explicit mass. The GM products are used when computing the ratio of Jupiter mass relative to other objects.

In 2015, the International Astronomical Union defined the nominal Jovian mass parameter to remain constant regardless of subsequent improvements in measurement precision of MJ. This constant is defined as exactly

${\displaystyle ({\mathcal {GM}})_{\mathrm {J} }^{\mathrm {N} }=1.266\,8653\times 10^{17}{\text{ m}}^{3}/{\text{s}}^{2}}$

If the explicit mass of Jupiter is needed in SI units, it can be calculated in terms of the gravitational constant, G by dividing GM by G.[9]

## Mass composition

The majority of Jupiter's mass is hydrogen and helium. These two elements make up more than 87% of the total mass of Jupiter.[10] The total mass of heavy elements other than hydrogen and helium in the planet is between 11 and 45 M.[11] The bulk of the hydrogen on Jupiter is solid hydrogen.[12] Evidence suggests that Jupiter contains a central dense core. If so, the mass of the core is predicted to be no larger than about 12 M. The exact mass of the core is uncertain due to the relatively poor knowledge of the behavior of solid hydrogen at very high pressures.[10]

## Relative mass

Masses of noteworthy astronomical objects relative to the mass of Jupiter
Object MJ / Mobject Mobject / MJ Ref
Sun 954.7919(15)×10−6 1047.348644±0.000017 [3]
Earth 317.82838 0.0031463520 [13]
Jupiter 1 1 by definition
Saturn 3.3397683 0.29942197 [note 1]
Uranus 21.867552 0.045729856 [note 1]
Neptune 18.53467 0.05395295 [note 1]
Gliese 229B 21–52.4 [14]
51 Pegasi b 0.472±0.039 [15]

## Notes

1. ^ a b c Some of the values in this table are nominal values, derived from Numerical Standards for Fundamental Astronomy[3] and rounded using appropriate attention to significant figures, as recommended by the IAU Resolution B3.[9]

## References

1. ^ a b "Planets and Pluto: Physical Characteristics". ssd.jpl.nasa.gov. Jet Propulsion Labritory. Retrieved 31 October 2017.
2. ^ Coffey, Jerry (18 June 2008). "Mass of Jupiter". Universe Today. Retrieved 2017-10-31.
3. ^ a b c "Numerical Standards for Fundamental Astronomy". maia.usno.navy.mil. IAU Working Group. Retrieved 31 October 2017.
4. ^ MacDougal, Douglas W. (November 6, 2012). "A Binary System Close to Home: How the Moon and Earth Orbit Each Other". Newton's Gravity. Undergraduate Lecture Notes in Physics. Springer New York. pp. 193–211. doi:10.1007/978-1-4614-5444-1_10. ISBN 9781461454434. the barycenter is 743,000 km from the center of the sun. The Sun's radius is 696,000 km, so it is 47,000 km above the surface.
5. ^ a b Seager, S.; Kuchner, M.; Hier-Majumder, C. A.; Militzer, B. (2007). "Mass-Radius Relationships for Solid Exoplanets". The Astrophysical Journal. 669 (2): 1279–1297. arXiv:0707.2895. Bibcode:2007ApJ...669.1279S. doi:10.1086/521346.
6. ^ How the Universe Works 3. Jupiter: Destroyer or Savior?. Discovery Channel. 2014.
7. ^ Guillot, Tristan (1999). "Interiors of Giant Planets Inside and Outside the Solar System". Science. 286 (5437): 72–77. Bibcode:1999Sci...286...72G. doi:10.1126/science.286.5437.72. PMID 10506563.
8. ^ Burrows, A.; Hubbard, W. B.; Saumon, D.; Lunine, J. I. (1993). "An expanded set of brown dwarf and very low mass star models". Astrophysical Journal. 406 (1): 158–71. Bibcode:1993ApJ...406..158B. doi:10.1086/172427.
9. ^ a b Mamajek, E. E; Prsa, A; Torres, G; et al. (2015). "IAU 2015 Resolution B3 on Recommended Nominal Conversion Constants for Selected Solar and Planetary Properties". arXiv:1510.07674 [astro-ph.SR].
10. ^ a b Guillot, Tristan; Stevenson, David J.; Hubbard, William B.; Saumon, Didier. "The Interior of Jupiter" (PDF). Retrieved 31 October 2017.
11. ^ Guillot, Tristan; Gautier, Daniel; Hubbard, William B. (December 1997). "New Constraints on the Composition of Jupiter from Galileo Measurements and Interior Models". Icarus. 130 (2): 534–539. arXiv:astro-ph/9707210. Bibcode:1997Icar..130..534G. doi:10.1006/icar.1997.5812.
12. ^ Öpik, E.J. (January 1962). "Jupiter: Chemical composition, structure, and origin of a giant planet". Icarus. 1 (1–6): 200–257. Bibcode:1962Icar....1..200O. doi:10.1016/0019-1035(62)90022-2.
13. ^ "Planetary Fact Sheet – Ratio to Earth". nssdc.gsfc.nasa.gov. Retrieved 2016-02-12.
14. ^ White, Stephen M.; Jackson, Peter D.; Kundu, Mukul R. (December 1989). "A VLA survey of nearby flare stars". Astrophysical Journal Supplement Series. 71: 895–904. Bibcode:1989ApJS...71..895W. doi:10.1086/191401.
15. ^ Martins, J. H. C; Santos, N. C; Figueira, P; et al. (2015). "Evidence for a spectroscopic direct detection of reflected light from 51 Peg b". Astronomy & Astrophysics. 576 (2015): A134. arXiv:1504.05962. Bibcode:2015A&A...576A.134M. doi:10.1051/0004-6361/201425298.