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To find a more precise measure of the mass requires knowledge of the inclination of the planet's orbit. A graph of measured radial velocity versus time will give a characteristic curve (sine curve in the case of a circular orbit), and the amplitude of the curve will allow the minimum mass of the planet to be calculated using the binary mass ...
Astrometry has been used to discover a handful number of exoplanets, mostly gas giants more massive than Jupiter. It is based on measuring a star's proper motion, and seeing how that position changes over time: a planet with a sufficiently large mass is able to gravitationally pull its host star, making its proper motion vary over large timescales.
The viewer is situated at the bottom. Light from the anticlockwise-rotating star is blue-shifted on the approaching side, and red-shifted on the receding side. As the planet passes in front of the star it sequentially blocks blue- and red-shifted light, causing the star's apparent radial velocity to change, but it does not in fact change.
The inclination will then be known, and the inclination combined with M sini from radial-velocity observations will give the planet's true mass. Also, astrometric observations and dynamical considerations in multiple-planet systems can sometimes provide an upper limit to the planet's true mass.
The true mass and true orbital velocity cannot be determined from the radial velocity because the orbital inclination is generally unknown. (The inclination is the orientation of the orbit from the point of view of the observer, and relates true and radial velocity. [1]) This causes a degeneracy between mass and inclination.
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. This method reveals planets by measuring changes in the movement of stars in the line-of-sight , so the real orbital inclinations and true masses of the planets are ...
The same method has also been used to detect planets around stars, in the way that the movement's measurement determines the planet's orbital period, while the resulting radial-velocity amplitude allows the calculation of the lower bound on a planet's mass using the binary mass function. Radial velocity methods alone may only reveal a lower ...
Tensiomyography (TMG) is a measuring method for detection of skeletal muscles' contractile properties. [1] Tensiomyography assesses muscle mechanical response based on radial muscle belly displacement induced by a single electrical stimulus. [2] It is performed using the TMG S2 system.