Alpha centauri distance
Pro Research Analysisby 
Searched over 200M research papers
Understanding the Distance to Alpha Centauri
Alpha Centauri System Overview
Alpha Centauri is the closest star system to our Solar System, located approximately 4.37 light-years away2 7. This system is composed of three stars: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. Alpha Centauri A and B are sun-like stars that orbit each other closely, while Proxima Centauri, a red dwarf, orbits the pair at a much greater distance2.
Measuring the Distance to Alpha Centauri
Parallax and Masses
The distance to Alpha Centauri has been measured using various methods, including parallax. Recent studies using the HARPS instrument have provided precise radial velocity data, confirming the parallax of Alpha Centauri to be approximately 743 milliarcseconds (mas), which places it slightly further away than some previous estimates8. This measurement also helps refine the masses of Alpha Centauri A and B to 1.13 and 0.97 solar masses, respectively8.
Gravitational Lensing
Gravitational lensing studies have also been conducted to understand the minimal focal distances of the stars in the Alpha Centauri system. For Alpha Centauri A, B, and Proxima Centauri, the minimal focal distances are approximately 679.263 AU, 563.485 AU, and 112.138 AU, respectively4. These distances are theoretical values derived from Einstein's deflection formula and provide insights into the gravitational influence of these stars4.
Exploring Alpha Centauri
FOCAL Mission Concept
The FOCAL mission concept proposes using the Sun as a gravitational lens to explore the Alpha Centauri system. This involves launching a spacecraft, FOCAL 1, to a distance of about 1000 AU from the Sun in the direction opposite to Alpha Centauri B. This spacecraft would act as a relay satellite, ensuring robust telecommunications across the 4.37 light-year distance1. A second spacecraft, FOCAL 2, would then be launched towards Alpha Centauri B, potentially taking around 50 years to reach its destination, depending on the propulsion system used1.
Deep Imaging Surveys
Deep imaging surveys using advanced instruments like the VLT-NACO and NTT-SUSI2 have been conducted to search for faint companions and background objects around Alpha Centauri B. These surveys have not detected any comoving companions down to a limiting magnitude of 19-20 in the H and Ks bands, setting the maximum mass of possible companions to 20-30 times that of Jupiter3 6. These findings help refine our understanding of the environment around Alpha Centauri and the potential for finding extrasolar planets.
Conclusion
Alpha Centauri, our closest stellar neighbor, continues to be a focal point for astronomical research. With precise measurements of its distance and mass, along with innovative mission concepts like FOCAL, we are steadily advancing our understanding of this intriguing star system. The ongoing efforts to explore and characterize Alpha Centauri will undoubtedly yield significant insights into the potential for habitable planets beyond our Solar System.
Sources and full results
Most relevant research papers on this topic
Going to Alpha Centauri B and setting up a Radio Bridge
The two stars' gravitational lenses and two FOCAL spacecrafts can create a robust telecommunication system for future space missions to the Alpha Centauri system.
Deep imaging survey of the environment of Alpha Centauri - I. Adaptive optics imaging of Alpha Cen B with VLT-NACO
This study did not detect any comoving companions to Alpha Centauri B, but found 252 background objects within 15" of the star, suggesting a maximum mass of 20-30 times Jupiter within 7-20 AU.
The gravitational lenses of alpha centauri a, b, c and of barnard's star
The gravitational lenses of Alpha Centauri A, B, and C (Proxima Centauri) are 679.263, 563.485, and 112.138 AU, respectively, with the Sun at 550 AU.
Deep imaging survey of the environment of Alpha Centauri - II. CCD imaging with the NTT-SUSI2 camera
This study did not detect any companion to Alpha Centauri between 100 and 300 AU, down to a maximum mass of 15 times Jupiter, and mostly excludes the presence of a companion more massive than 30 MJup between 50 and 100 AU.
Alpha Centauri
Alpha Centauri is the nearest star to the Sun, with a triple system consisting of Cen A, Cen B, and Proxima Cen (V645 Cen) as its main pointers.
Highly Cited