What is a planet?
@article{Soter2007WhatIA, title={What is a planet?}, author={Steven L. Soter}, journal={Scientific American}, year={2007}, volume={296 1}, pages={ 34-41 } }
A planet is an end product of disk accretion around a primary star or substar. I quantify this definition by the degree to which a body dominates the other masses that share its orbital zone. Theoretical and observational measures of dynamical dominance reveal gaps of 4-5 orders of magnitude separating the eight planets of our solar system from the populations of asteroids and comets. The proposed definition dispenses with upper and lower mass limits for a planet. It reflects the tendency of…
37 Citations
The Worlds Out There
- Geology, Physics
- 2010
A planet is one of the possible byproducts accompanying the formation of a star. In this chapter, we define first what we mean by ‘planet’ and describe the main types of bodies found in our solar…
A QUANTITATIVE CRITERION FOR DEFINING PLANETS
- Geology, Physics
- 2015
© 2015. The American Astronomical Society. All rights reserved. A simple metric can be used to determine whether a planet or exoplanet can clear its orbital zone during a characteristic time scale,…
Astronomy: Bound and unbound planets abound
- Physics, GeologyNature
- 2011
Gravitational microlensing observations in the direction of the Galactic Bulge have come up with a surprising result: the discovery of ten previously unknown extrasolar planets that are not bound to host stars.
Physical and dynamical characteristics of icy “dwarf planets” (plutoids)
- Physics, GeologyProceedings of the International Astronomical Union
- 2009
Abstract The geophysical and dynamical criteria introduced in the “Definition of a Planet in the Solar System” adopted by the International Astronomical Union are reviewed. The classification scheme…
Gravitational clearing of natural satellite orbits
- Physics, GeologyPublications of the Astronomical Society of Australia
- 2022
Abstract The distribution of diameters and orbital distances from the parent body of 156 named moons of the planets in the Solar System is not random. All 11 moons with diameters larger than …
The Moon Meets All Requirements of the IAU Definition for “Planet”
- Physics, Geology
- 2017
The Earth-Moon system has often been characterized as having some characteristics of a “double planet” system. It is demonstrated that while the orbital barycenter of the Earth-Moon pair lies inside…
What Is a Galaxy? Cast Your Vote Here
- PhysicsPublications of the Astronomical Society of Australia
- 2011
Abstract Although originally classified as galaxies, Ultra-Compact Dwarfs (UCDs) have many properties in common with globular star clusters. The debate on the origin and nature of UCDs, and the…
References
SHOWING 1-10 OF 60 REFERENCES
Disks Around Stars and the Growth of Planetary Systems
- Physics, GeologyScience
- 2005
High-resolution spectroscopy is uncovering planetary dynamics and motion within the remnant disk, and imaging at infrared to millimeter wavelengths resolves disk structure over billions of years of evolution.
On the number of planets in the outer solar system: Evidence of a substantial population of 1000-km bodies
- Geology, Physics
- 1991
Free-floating Planets in Orion
- Physics, GeologyScience
- 2000
ASTRONOMY
Extrasolar planets and brown dwarfs have been discovered with increasing frequency around young stars, yet still more discoveries will be needed to understand conditions under which a star…
Giant planet migration through the action of disk torques and planet-planet scattering
- Physics, Geology
- 2005
The Kuiper Belt and the Solar System's Comet Disk
- Physics, GeologyScience
- 2005
A growing body of evidence indicates that the sculpting of the Kuiper belt region may have involved large-scale planetary migration, the presence of other rogue planetary objects in the disk, and/or the close passage of other stars in the Sun's birth cluster.
A Disk Census for Young Brown Dwarfs
- Physics, Geology
- 2003
Recent surveys have identified substellar objects down to planetary masses in nearby star-forming regions. Reliable determination of the disk frequency in young brown dwarfs is of paramount…
Final Stages of Planet Formation
- Geology, Physics
- 2004
We address three questions regarding solar system planets: What determined their number? Why are their orbits nearly circular and coplanar? How long did they take to form?
Runaway accretion in a…
Solar system: A planet more, a planet less?
- Physics, GeologyNature
- 2006
Further observations of an object dubbed 2003 UB313, which lies beyond Neptune, show that its diameter is around 3,100 kilometres. This makes it larger than Pluto, the smallest ‘traditional’ Solar…
Discovery of Young, Isolated Planetary Mass Objects in the σ Orionis Star Cluster
- Physics, Geology
- 2000
We present the discovery by optical and near-infrared imaging of an extremely red, low-luminosity population of isolated objects in the young, nearby stellar cluster around the multiple, massive star…
Planetesimals to brown dwarfs: What is a planet?
- Geology, Physics
- 2006
The past 15 years have brought about a revolution in our understanding of our Solar System and other planetary systems. During this time, discoveries include the first Kuiper belt objects (KBOs), the…