LIBRA

The constellation Libra is not very easy to see in the sky, it was once joined with the constellation Scorpius, which we understand from the names of the main stars Zubeneschamali or the ‘northern claw’ and Zubenelgenubi, the ‘southern claw’ referring to the ancient constellation of Scorpius. These two stars are now part of Libra’s scales.

After its separation from the constellation of Scorpius, Libra today is depicted as and connected to the Virgin. It is this female figure to hold the weighing scales which for the ancient Romans represented the equilibrium of all the constellations as the Sun moved through its stars during the autumn equinox.

Although Zubeneschamali is the Beta star, it is the brightest in the constellation. In ancient times, its brightness was considered the same as Antares in Scorpius but we are not certain if that was due to its variability or to an inferior luminosity of the alpha star in Scorpius in antiquity. It is 185 light-years from us and is 400 times brighter than the Sun. It has a greenish color when seen through a telescope.

Zubenelgenubi is the Alpha star and is the second brightest in the constellation. It is a multiple star system divisible into two stars easily seen through binoculars. The two stars rotate around their center of mass over a period of more than 200,000 years. The two companions in their turn are spectroscopic double stars, a quadruple star system - 77 light-years from the Solar System.