Sirius, also known as Sirius, is the brightest star in the entire celestial vault from Earth’s perspective. It is easily identifiable in the night sky and although from our limited view we only see a flash of light, it is actually a binary system composed of Sirius A and Sirius B.
The stellar objects in our cosmos are constant explosions of gas that are burning millions of light years from Earth. However, its light is so powerful that it travels through myriads of kilometers through space-time until it reaches our Earth and it is possible to admire it every night. This is how the starry view that the vault gives us night after night is composed.
Not all stars are the same size and much less are they at the same distance, which is why we can admire a whole diversity of sizes and sparkles. Of course, the most luminous bodies that cross the sky are represented by the Greater Star that gives us light every day and at night, we have the sweet Selene, as the Moon was called by the Greeks. Then there would be some when they pass through their perigees, but of all the stars Sirius is the most luminous among a sea of hundreds of millions of stellar bodies. This is why it is so special.
Sirius in ancient times
Sirius or Sirius, has appeared in ancient texts precisely because it is the star that shines brightest at night. And precisely its name comes from the ancient Greek Σείριος (Seirios) which means ‘the brightest’ and which was later translated into Latin as Sirius, whose translation is the same.
The first ancient text that tells us about Sirius is the one written by Hesiod in his poetic work ‘Works and Days’, which dates back to the 7th century BC. Although the Greeks were not the only ones who gave great importance to Sirius for being the most notable star. from the sky, in North America traditional people called it the ‘Wolf Star’ and, for their part, ancient Chinese cultures associated it with the name ‘Heavenly Wolf’.
Its relationship with canids is not coincidental, in fact in the current catalogue, Sirius is the alpha star of the constellation of the Greater Dog (Canis Maior), even today it is still called the ‘Dog Star’. This is because it belongs to a group of stars that, if observed closely, have the shape of a canid, which is why it has been associated with wolves or dogs since ancient times.
Sirius and its luminosity magnitude
When talking about magnitudes of luminous bodies in the sky, two considerations are taken into account to determine a specific value. That is, there are two types of magnitudes: absolute and apparent. These depend on two different factors, the first is given by the intrinsic brightness of the stars, that is, how luminous they are if we could observe them at a given distance that is the same for all measurements.
The second does not depend only on the intrinsic brightness of each star, but is rather the brightness that is perceived from the terrestrial perspective combined with the possible extinctions of light by cosmic dust. In other words, the apparent magnitude is the value given to the luminosity of a body seen from the terrestrial perspective. This is why, although it depends on the absolute magnitude of the star, the distance at which it is from the Earth also plays a role. In this second category, Sirius takes the crown.
Sirius is located about 8.6 light years from the Solar System, in that sense, it is not exactly the closest star, that title goes to Alpha Centauri which is 4.3 light years away. But Sirius beats it in apparent magnitude, with a magnitude of -1.4 which means that the lower the value, the brighter the object.
According to NASA, Sirius has a total mass of two suns, which means that it is twice as large as our largest star and taking into account that it is relatively close to Earth, this is why we can see it very large in the dome.
How to find Sirius in the sky
Fortunately for lovers of astronomical observation, finding Sirius in the sky is very simple, you can use the belt of . The three stars that are grouped in a diagonal line point downwards to the left and following that imaginary line drawn by the belt, you just have to move your eyes a little over it and you will find Sirius. To be more specific, its exact position is:
Not alone
In 1844, astronomer Friedrich Wilhelm Bessel published a note in Monthly Notices of the Royal Astronomical Society describing how Sirius was deviating from its predicted motion in the sky. Bessel’s said it was likely that a companion was affecting the star’s motion.
*Photograph taken by him showing the enormous difference in size between Sirius A and its companion Sirius B, which can be seen above left. Credit: NASA/ESA/H. Bond/M. Barstow.
But it was not until 1862 when Alvan Graham Clark, a telescope-making astronomer, that Bessel’s theory was confirmed. Clark discovered that Sirius was actually a binary system composed of Sirius A and Sirius B. The latter was discovered to be one that orbits its giant companion.
Sirius B is much smaller than its companion, according to NASA, its brightness is about 10 thousand times dimmer than that of Sirius A. But together, they form a system that, from our perspective, is crowned as the brightest star of all. the sky.