Planetary discriminant

The planetary discriminant μ was introduced by Steven Soter in connection with the question of the planet definition . It indicates the ratio of the mass of a body located in the solar system to the mass of the other objects in its orbit and their surroundings, provided that these are not moons or celestial bodies rotating in a resonant manner.

The following table contains the values of the planetary discriminant for all currently known planets and several dwarf planets . The currently eight known planets of the solar system according to the definition of the International Astronomical Union (IAU) from 2006 have a value μ greater than 100, dwarf planets a value less than 100.

Furthermore, the Stern-Levison parameter is also given normalized to the earth. It is defined as . It is ${\ displaystyle \ Lambda = k {\ frac {M ^ {2}} {P}} = {\ frac {T} {\ tau}}}$

${\ displaystyle M}$ the mass of the object
${\ displaystyle P}$ the period of rotation of the object
${\ displaystyle T = {\ frac {1} {H_ {0}}}}$ the Hubble time
${\ displaystyle \ tau}$ Duration to remove smaller objects from the web area
${\ displaystyle k}$ a constant typical for the respective system

The size of these parameters was developed for observing planets around foreign stars and indicates how strongly a planet controls its surroundings. For the earth, Λ _{E is} about 150,000.

rank	Surname	Planetary discriminant μ	Stern-Levison-P. Λ / Λ _E	Mass (in kg)	Object type
1	earth	1 700 000000	1.00e⁰	5.9736e²⁴	3rd planet
2	Venus	1 350 000000	1.08e⁰	4th.8685e²⁴	2nd planet
3	Jupiter	625 000000	8th.51e³	1.8990e²⁷	5th planet
4th	Saturn	190 000000	3.08e²	5.6846e^26th	6th planet
5	Mercury	91 000000	1.26the^-2	3.3020e²³	1st planet
6th	Uranus	29 000000	2.51e⁰	8th.6832e^25th	7th planet
7th	Neptune	24 000000	1.79e⁰	1.0243e^26th	8th planet
8th	Mars	5 100000	6th.10e^-3	6th.4185e²³	4th planet
9	Ceres	0.33	8th.70e^-9	9.3500e^20th	Dwarf planet
10	Eris	0.10	3.50e^-8th	1.6600e^22nd	Dwarf planet
11	Pluto	0.07	1.95e^-8th	1.2500e^22nd	Dwarf planet

Web links

Steven Soter: What is a Planet? In: The Astronomical Journal , August 16, 2006, arxiv : astro-ph / 0608359

Individual evidence

↑ ^a ^b Steven Soter: What is a planet? In: The Astronomical Journal . tape 132 , no. 6 , August 16, 2006, ISSN 0004-6256 , p. 2513-2519 , doi : 10.1086 / 508861 , arxiv : astro-ph / 0608359 .

[soter-1] Steven Soter: What is a planet? In: The Astronomical Journal . tape 132 , no. 6 , August 16, 2006, ISSN 0004-6256 , p. 2513-2519 , doi : 10.1086 / 508861 , arxiv : astro-ph / 0608359 .