- historical event:
- Around 10,000 so-called extrasolar planets (exoplanets) have been discovered over the last decade or so. The closest of these planets is Alpha Centauri Bb.
A celestial body which is believed to be the closest extrasolar planet to Earth was discovered on this day in 2012. It has the provisional name of Alpha Centauri Bb, and its existence has yet to be conclusively proved. Around 10,000 so-called extrasolar planets (exoplanets) have been discovered over the last decade or so. Alpha Centauri Bb would be the closest of these to our own world, because the Alpha Centauri system is the closest to our own Sun. Alpha Centauri is believed to be a binary system i.e. a system comprised of two stars – Alpha Centauri A and Alpha Centauri B – which revolve around a common center of mass. A red dwarf star, Proxima Centauri, is also associated with the system.
The planet Alpha Centauri Bb is called so because it revolves around the star Alpha Centauri B. That star is not only smaller and lighter than our Sun, but is also somewhat colder, and orange in color.
The aforementioned planet is likely of similar size to our own. However, it is not located within the so-called habitable zone of its star. Namely, it has been theorized that the planet revolves around Alpha Centauri B at a distance which is roughly 25 times smaller than the Earth’s distance from the Sun, and 10 times smaller than Mercury’s. Therefore, the surface of that planet would be extremely hot – around 1,200 °C.