The Closest Distance Between Stars: From Contact Binaries to Proxima Centauri

Space is vast, yet intimate distances between stars do exist. This article explores the closest stellar pairs and their fascinating characteristics, including the intriguing concept of contact binaries and the Thorne–ytkow object exemplified by binary systems like Proxima Centauri and its neighbors Alpha Centauri A and B.

The Proxima Centauri and Alpha Centauri Star System

The closest known stars to each other are Proxima Centauri, Alpha Centauri A, and Alpha Centauri B, which form a triple star system. Here’s a detailed overview:

Proxima Centauri

Distance from Earth: Approximately 4.24 light-years Size: A red dwarf of spectral type M5.5, about 14 times the mass of the Sun Diameter: Roughly 1/7th that of the Sun

Alpha Centauri A and B

Distance from Earth: Approximately 4.37 light-years Alpha Centauri A: Similar to the Sun, about 1.1 times the mass and 1.2 times the diameter of the Sun with a spectral type of G2 Alpha Centauri B: Slightly smaller than the Sun, about 0.9 times the mass and 0.86 times the diameter with a spectral type of K1

The distance between Proxima Centauri and the Alpha Centauri pair is approximately 0.21 light-years, or about 13,000 AU or 2.0 trillion kilometers. Proxima Centauri orbits the Alpha Centauri binary system at a much greater distance compared to the separation of the binary stars.

Contact Binaries: Stars Touching and Merging

Not all close stellar systems involve vast distances. In the case of contact binaries, the stars are in direct contact or share their gaseous envelopes. This is the closest distance that two stars can have while still orbiting each other. Contact binaries can be described as a pair of interacting stars that have become so close that their outer layers overlap and merge, sharing a common atmosphere.

Theoretically, the distance between two stars in a contact binary could be as close as 'zero,' meaning the surfaces of the two stars are touching. However, this is purely a theoretical scenario and is not observed in nature as a stable configuration for extended periods. Instead, contact binaries often lead to the merger of the stars, forming a more massive single star.

The Thorne–Ypsilantis Object: A Binary Merged into a Monster

Another interesting concept is the Thorne–Ypsilantis object, a supermassive, highly compact object formed from the merger of a red giant or supergiant with a neutron star. This merger results in an extreme object with properties of both a neutron star and a black hole, often causing significant gravitational disturbances.

In an artist's rendition, you might envision the composite object as a Thorne–Ypsilantis star, where the red giant or supergiant core has been fully engulfed by the neutron star, creating a hybrid stellar monster. This object would be a fascinating subject for further astronomical research and could provide insights into the most extreme conditions in the universe.

The closest distance between two stars can vary greatly, from the theoretical zero in contact binaries to the 4.37 light-years that separate Alpha Centauri A and B. Understanding these close stellar systems helps us grasp the intricate nature of stellar evolution and the fascinating physics that govern the universe.