A report on Binary star, Double star and Alpha Centauri

Binary system of two stars
Astronomers have mistakenly reported observations of a double star in place of J 900 and a faint star in the constellation of Gemini.
Alpha Centauri is the brightest object in the constellation of Centaurus (top left).
Edge-on disc of gas and dust present around the binary star system HD 106906
Artist's impression of the discs around the young stars HK Tauri A and B.
Apparent and true orbits of Alpha Centauri. The A component is held stationary, and the relative orbital motion of the B component is shown. The apparent orbit (thin ellipse) is the shape of the orbit as seen by an observer on Earth. The true orbit is the shape of the orbit viewed perpendicular to the plane of the orbital motion. According to the radial velocity versus time, the radial separation of A and B along the line of sight had reached a maximum in 2007, with B being further from Earth than A. The orbit is divided here into 80 points: each step refers to a timestep of approx. 0.99888 years or 364.84 days.
Algol B orbits Algol A. This animation was assembled from 55 images of the CHARA interferometer in the near-infrared H-band, sorted according to orbital phase.
The relative sizes and colours of stars in the Alpha Centauri system, compared to the Sun
Artist's conception of a cataclysmic variable system
Relative positions of Sun, Alpha Centauri AB and Proxima Centauri. Grey dot is projection of Proxima Centauri, located at the same distance as Alpha Centauri AB.
Artist's impression of the binary star system AR Scorpii
The two bright stars at the lower right are Alpha (right) and Beta Centauri (left, above antenna). A line drawn through them points to the four bright stars of the Southern Cross, just to the right of the dome of the Danish 1.54 m telescope at La Silla Observatory in Chile.
Artist rendering of plasma ejections from V Hydrae
Alpha Centauri AB taken in daylight by holding a Canon Powershot S100 in line with the eyepiece of a 110-mm refractor. The photo is one of the best frames of a video. The double star is clearly visible.
Artist's impression of the sight from a (hypothetical) moon of planet HD 188753 Ab (upper left), which orbits a triple star system. The brightest companion is just below the horizon.
View of Alpha Centauri from the Digitized Sky Survey-2
Schematic of a binary star system with one planet on an S-type orbit and one on a P-type orbit
Alpha Centauri A is of the same stellar type G2 as the Sun, while Alpha Centauri B is a K1-type star.
The two visibly distinguishable components of Albireo
Closest stars to the Sun
Luhman 16, the third closest star system, contains two brown dwarfs.
Distances of the nearest stars from 20,000 years ago until 80,000 years in the future
Planet Lost in the Glare of Binary Stars (illustration)
Animation showing motion of Alpha Centauri through the sky. (The other stars are held fixed for didactic reasons) "Oggi" means today. "Anni" means years.
The discovery image of Alpha Centauri's candidate Neptunian planet, marked here as "C1".
Looking towards the sky around Orion from Alpha Centauri with Sirius near Betelgeuse, Procyon in Gemini, and the Sun in Cassiopeia generated by Celestia.
Simulated night-sky image with a "W" of stars from Cassiopeia connected by lines, and the Sun, labeled "Sol", as it would appear to the left of the "W"
The Very Large Telescope and Alpha Centauri

This occurs because the pair either forms a binary star (i.e. a binary system of stars in mutual orbit, gravitationally bound to each other) or is an optical double, a chance line-of-sight alignment of two stars at different distances from the observer.

- Double star

Alpha Centauri A and B are Sun-like stars (Class G and K, respectively), and together they form the binary star Alpha Centauri AB.

- Alpha Centauri

The more general term double star is used for pairs of stars which are seen to be close together in the sky.

- Binary star

Alpha Centauri

- Double star

For example, in about 6,200 AD, α Centauri's true motion will cause an extremely rare first-magnitude stellar conjunction with Beta Centauri, forming a brilliant optical double star in the southern sky.

- Alpha Centauri

Orbital periods can be less than an hour (for AM CVn stars), or a few days (components of Beta Lyrae), but also hundreds of thousands of years (Proxima Centauri around Alpha Centauri AB).

- Binary star
Binary system of two stars

1 related topic with Alpha

Overall
Star system named DI Cha. While only two stars are apparent, it is actually a quadruple system containing two sets of binary stars.

Star system

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Small number of stars that orbit each other, bound by gravitational attraction.

Small number of stars that orbit each other, bound by gravitational attraction.

Star system named DI Cha. While only two stars are apparent, it is actually a quadruple system containing two sets of binary stars.
Orbits of the HR 6819 hierarchical triple star system: an inner binary with one star (orbit in blue) and a black hole (orbit in red), encircled by another star in a wider orbit (also in blue).
Subsystem notation in Tokovinin's Multiple Star Catalogue
Sirius A (center), with its white dwarf companion, Sirius B (lower left) taken by the Hubble Space Telescope.
HD 98800 is a quadruple star system located in the TW Hydrae association.

A star system of two stars is known as a binary star, binary star system or physical double star.

Alpha Centauri is a triple star composed of a main binary yellow dwarf pair (Alpha Centauri A and Alpha Centauri B), and an outlying red dwarf, Proxima Centauri. Together, A and B form a physical binary star, designated as Alpha Centauri AB, α Cen AB, or RHD 1 AB, where the AB denotes this is a binary system. The moderately eccentric orbit of the binary can make the components be as close as 11 AU or as far away as 36 AU. Proxima Centauri, also (though less frequently) called Alpha Centauri C, is much farther away (between 4300 and 13,000 AU) from α Cen AB, and orbits the central pair with a period of 547,000 (+66,000/-40,000) years.