Planetesimals to brown dwarfs: What is a planet?

  title={Planetesimals to brown dwarfs: What is a planet?},
  author={Gibor S. Basri and Michael E. Brown},
  journal={Annual Review of Earth and Planetary Sciences},
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 first brown dwarfs, and the first extrasolar planets. Although discoveries continue apace, they have called into question our previous perspectives on planets, both here and elsewhere. The result has been a debate about the meaning of the word “planet” itself. It is clear that scientists do not… 

Figures from this paper

Extra-Solar Planetary Systems
In this chapter we expand our view to include planetary systems beyond our own. We begin with the historical searches for planets around other stars to the present day, then survey the methods used
The SOPHIE search for northern extrasolar planets - IV. Massive companions in the planet-brown dwarf boundary
Context. The mass domain where massive extrasolar planets and brown dwarfs lie is still poorly understood. Indeed, not even a clear dividing line between massive planets and brown dwarfs has been
The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs
  • J. Bailey
  • Geology, Physics
    Publications of the Astronomical Society of Australia
  • 2014
Abstract The last few years has seen a dramatic increase in the number of exoplanets known and in the range of methods for characterising their atmospheric properties. At the same time, new
The physical properties of extra-solar planets
Tremendous progress in the science of extrasolar planets has been achieved since the discovery of a Jupiter orbiting the nearby Sun-like star 51 Pegasi in 1995. Theoretical models have now reached
Limb-darkening Measurements on Exoplanet Host Stars and the Sun
After the discovery of the first planets orbiting solar-like stars at the end of the last century, the study of these exoplanets has become a new field in astronomy with increasing popularity. The
Evolution of Debris Disks
Circumstellar dust exists around several hundred main sequence stars. For the youngest stars, that dust could be a remnant of the protoplanetary disk. Mostly it is inferred to be continuously
10.01 – Overview
What is a planet?
  • S. Soter
  • Physics, Geology
    Scientific American
  • 2007
The proposed definition dispenses with upper and lower mass limits for a planet and reflects the tendency of disk evolution in a mature system to produce a small number of relatively large bodies (planets) in nonintersecting or resonant orbits, which prevents collisions between them.


What Is a Planet?
It is maintained that cool objects found in young star clusters in Orion and Perseus are better thought of as low-mass brown dwarfs, as they are not in orbit around stars.
Observations of Brown Dwarfs
▪ Abstract The brown dwarfs occupy the gap between the least massive star and the most massive planet. They begin as dimly stellar in appearance and experience fusion (of at least deuterium) in their
The Kepler Mission: A Mission to Determine the Frequency of Inner Planets Near the Habitable Zone of a Wide Range of Stars
The surprising discovery of giant planets in inner orbits around solar-like stars has brought into question our understanding of the development and evolution of planetary systems, including our
▪ Abstract Eight extrasolar planet candidates have now been identified, all revealed by Keplerian Doppler shifts in their host stars. The masses (m sin i) lie between 0.5 and 7 MJUP, and the
Discovery of the candidate Kuiper belt object 1992 QB1
THE apparent emptiness of the outer Solar System has been a long-standing puzzle for astronomers, as it contrasts markedly with the abundance of asteroids and short-period comets found closer to the
A planetary system around the millisecond pulsar PSR1257 + 12
MILLISECOND radio pulsars, which are old (∼109yr), rapidly rotating neutron stars believed to be spun up by accretion of matter from their stellar companions, are usually found in binary systems with
A population of very young brown dwarfs and free‐floating planets in Orion
We describe the results of a very deep imaging survey of the Trapezium cluster in the IJH bands, using the UKIRT high-resolution camera UFTI. Approximately 32 per cent of the 515 point sources
Giant Planet Companion to 2MASSW J1207334-393254
We report new VLT/NACO imaging observations of the young, nearby brown dwarf 2MASSW J1207334-393254 and its suggested planetary mass companion (2M1207 b). Three epochs of VLT/NACO measurements
We investigate the formation of planetesimals via the gravitational instability of solids that have settled to the midplane of a circumstellar disk. Vertical shear between the gas and a subdisk of
Discovery of a Planetary-sized Object in the Scattered Kuiper Belt
We present the discovery and initial physical and dynamical characterization of the object 2003 UB313. The object is sufficiently bright that for all reasonable values of the albedo it is certain to