LARGEST BODIES OF THE SOLAR SYSTEM

Compiled by Haluk Akcam - updated June 18, 2006

Notes:

Semi-major axis (a) unit is AU for the objects revolving the Sun, and km for the satellites of the planets.

1 AU = 149,597,870.691 ± 0.003 km ( = ct_A )

Sidereal orbital periods are in days up to Neptune, and in Julian years for TNOs, including Pluto.

1 Gaussian year = 365.256 8983 days ( a = 1 AU)

1 Sidereal year = 365.256 36300 days (epoch J2000.0)

1 Tropical year = 365.242 19040 days (epoch J2000.0)

1 Julian year = 365.25 days

Radii are given as volumetric mean radius.

Planetary and satellite orbital elements are for J2000.0, planetoid elements are oscillating ones (JPL-DASTCOM).

Planetoids with r < 300 km are ignored.

Geocentric angular diameters are calculated for mean limits.

Fractional parts of the figures are truncated.

Radius figures for recently discovered TNOs are estimated values based mostly on infrared (thermal) measurements.

Some big TNOs are specially designated, such as Sedna (2003VB12), Orcus (2004DW), Quaoar (2002LM60), Varuna (2000WR106), Chaos (1998WH24), and Ixion (2001KX76).

The order of the planetary size sequence seems shattered after the newly discovered 2003UB313, which is expected to have a larger size than Pluto. It is quite possible that the sequence will change again in the very future, after discoveries of new TNOs.

Visibility:

Out of these 49 bodies, only seven are visible to the naked eye: The two luminaries (Moon, Sun), and five planets (Venus, Jupiter, Mars, Saturn, Mercury). Sometimes, Uranus can be faintly visible, depending on the orbital position. Although rarely, Mars can be also invisible to the naked eye, due to its orbital position. Lower visibility limit for the unaided healthy eye is around 3.8 seconds of arc, for stationary objects with moderate albedos, on a pitch-black background.

Uranus and Neptune are observable with the aid of an amateur telescope, as well as the Galilean satellites of Jupiter (Ganymede, Callisto, Io, and Europa). Under good conditions, the biggest satellite of Saturn (Titan), and the only amplest asteroid Ceres can be also observable. Perhaps, Rhea and Iapetus of Saturn may be spotted by keen eyes. Yet, other objects require some developed equipments.

Radial Classification:

Classification of the Solar system bodies based on radial correlations, can be arranged by transposing the quantitative relation of the first two elements. Since the radial ratio between Sun and Jupiter is 9.9554 ±0.0009, the next fitting object is Earth, with a ratio of 10.9733 ±0.0010 relative to Jupiter. The deviation of this sequence is  r_J² / ( r_S × r_E ) = 1.1023 ±0.0002, namely about 10 %. Following the same pattern, we obtain a numerical value of round 527 km for the radius of the next object of the sequence, after Earth: r_S × ( r_E / r_J )³ = 526.73 ±0.14

Thus, the fourth object of the sequence is surely not among the asteroids, but can be one of the large TNOs.

In the list of descending radial order, between Sun and Jupiter, there isn't any other body. But, between Jupiter and Earth, there are 3 bodies; Saturn, Uranus, and Neptune, which may constitute further three similar sub-sequences with Venus, Mars, and Mercury, respectively. For further details on this subject, please refer to the article.

Pictorial Presentation:

Copyright © 2006 Haluk Akcam. All rights reserved.

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