Rigel is one of the brightest stars in the night sky and is part of the constellation Orion. It is located approximately 860 light-years away and is a multi- star system. The main star, Rigel A, is classified as a blue supergiant. The other stars orbit each other closely and consist of three blue main sequence stars. Rigel is the brightest star in the constellation Orion and the seventh brightest star in the night sky. Its apparent magnitude varies slightly but not significantly, and it is visible in light-polluted skies. 

     Rigel is an extraordinarily large star, estimated to have 17 times the mass of our Sun. This star is incredibly bright, with a luminosity around 120,000 times that of the Sun. Its high luminosity is due to its massive size and intense energy output.  Rigel’s surface temperature reaches up to 10,000 Kelvin (about 18,000 degrees Fahrenheit). This high temperature produces its distinctive blue-white color.

     Rigel has reached an advanced stage in its stellar evolution. Massive stars like Rigel burn through their nuclear fuel more quickly than smaller stars like the Sun.  This quick consumption of fuel leads to short life, in the order of millions of years.  Star like Rigel have already burned through their primary fuel sources, such as hydrogen and helium, in their cores, and have begun fusing heavier elements. This fusion process generates tremendous energy, which sustains the star's luminosity and prevents it from collapsing under its gravity. High-mass stars, such as Rigel, undergo a more explosive end when they exhaust their nuclear fuel. When nuclear fusion ceases in the core, gravity causes the core to collapse rapidly. The collapse triggers a supernova explosion, where the outer layers of the star are violently expelled into space, producing an extremely bright burst of radiation that can outshine entire galaxies. The core of the star may collapse further, forming either a neutron star or, in the case of the most massive stars, a black hole.

     Rigel is part of a stellar system that contains at least four components. Rigel A is the largest star and the one that is closest to becoming a supernova. The secondary star, called Rigel B, is a spectroscopic binary star with stars Ba and Bb. Both are blue main sequence stars that are approximately 3 times more massive than our sun.  These two stars cannot be resolved through an optical telescope.  They are spectroscopic binary stars, which means they can only be detected by analyzing a star’s light. Rigel C orbits the Rigel B binaries, forming a close triple system. Since these 3 stars are so close together, it is difficult to understand each star’s individual properties. Rigel A is by far the most dominant star of the system in terms of size, however, it is far away from its companions at a distance of 2,200 astronomical units. It is estimated that Rigel A and the triple Rigel BC system have an orbital period of 24,000 years. As time goes on and our technology continues to advance, we will be sure to learn more about Rigel and each individual star in this system. 

Photo Credit: Screenshot from Star Visualization website called 100,000 Stars (https://stars.chromeexperiments.com/)

Additional Resources to Explore:

▶ Stellarium online planetarium: https://stellarium-web.org/ 

▶ 100,000 Stars: https://stars.chromeexperiments.com/