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Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant stars. By extension, it is a method for determining the distance to the star through trigonometry, the stellar parallax method .
Stellar parallax motion from annual parallax. Half the apex angle is the parallax angle. Parallax is an angle subtended by a line on a point. In the upper diagram, the Earth in its orbit sweeps the parallax angle subtended on the Sun. The lower diagram shows an equal angle swept by the Sun in a geostatic model.
Measurement of annual parallax was the first reliable way to determine the distances to the closest stars. The first successful measurements of stellar parallax were made by Friedrich Bessel in 1838 for the star 61 Cygni using a heliometer. [16] Stellar parallax remains the standard for calibrating other measurement methods.
Stellar parallax motion from annual parallax. Half the apex angle is the parallax angle. Parallax is an angle subtended by a line on a point. In the upper diagram, the Earth in its orbit sweeps the parallax angle subtended on the Sun. The lower diagram shows an equal angle swept by the Sun in a geostatic model.
As a parsec (parallax-second) is defined by the distance of an object that would appear to move exactly one second of arc against background objects, stars less than 5 parsecs away will have measured parallaxes of over 0.2 arcseconds, or 200 milliarcseconds.
Aberration is distinct from parallax, which is a change in the apparent position of a relatively nearby object, as measured by a moving observer, relative to more distant objects that define a reference frame. The amount of parallax depends on the distance of the object from the observer, whereas aberration does not.
Stellar proper motions have been used to infer the presence of a super-massive black hole at the center of the Milky Way. [18] This now confirmed to exist black hole is called Sgr A*, and has a mass of 4.3 × 10 6 M ☉ (solar masses). Proper motions of the galaxies in the Local Group are discussed in detail in Röser. [19]
Pages Related to Stellar properties, Pages using the word stellar in a physics context. ... Stellar occultation; Stellar parallax; Stellar physics; Stellar planetary;