The brightest star in the night sky that shimmers blue-white.
Sirius is the brightest star in the night sky and easily visible in the winter sky. Even though it belongs to the constellation Canis Major, the Greater Dog, it can be found by looking for the prominent Orion constellation as it is located just below the left foot star of Orion. At 8.6 light-years away, Sirius is one of the nearest stars and appears as a brilliant blue-white single star. But it is actually a binary system consisting of a 2 solar mass star and a very faint 1 solar mass white dwarf star, an extremely compact Earth-sized remnant of a once even more massive star than Sirius. The system is about 250 million years old.
The bright blue-white Sirius as it is visible with the naked eye. The diffraction spikes are an optical effect arising from the brightness of the star.
Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester)
X-ray image of the binary system in which the very hot and exposed white dwarf shines extremely bright whereas Sirius is the faint companion due its light being mostly UV and optical light.
The white dwarf was not discovered until 1862 by Alvan Clark.