Minimum mass

Minimum mass is a widely cited statistic for extrasolar planets detected by the radial velocity method or Doppler spectroscopy, and is determined using the binary mass function.

[4] Planets with orbits highly inclined to the line of sight from Earth produce smaller visible wobbles, and are thus more difficult to detect.

One of the advantages of the radial velocity method is that eccentricity of the planet's orbit can be measured directly.

One of the main disadvantages of the radial-velocity method is that it can only estimate a planet's minimum mass (

[7] Methods used to determine the true mass of a planet include measuring the distance and period of one of its satellites,[8] advanced astrometry techniques that use the motions of other planets in the same star system,[7] combining radial velocity techniques with transit observations (which indicate very low orbital inclinations),[9] and combining radial velocity techniques with stellar parallax measurements (which also determine orbital inclinations).

Let a line through the origin, making an angle of θ with the positive half of the x-axis, intersect the unit circle.

With a mass only 93 times that of Jupiter (MJ), or .09 M☉, AB Doradus C, a companion to AB Doradus A, is the smallest known star undergoing nuclear fusion in its core.

[13][14] Smaller bodies are called brown dwarfs, which occupy a poorly defined grey area between stars and gas giants.

A view of inclination that would appear flat upon the green plane from Earth.
Unit circle: the radius has length 1. The variable t measures the angle referred to as θ in the text.
Animation showing how the sine function (in red) is graphed from the y -coordinate (red dot) of a point on the unit circle (in green) at an angle of θ .