What is the brightest star in the night sky?

What is the brightest star in the night sky?

It is called Sirius (or Sirius) and is 8,611 light-years away from Earth

At night you can not miss the spectacle of looking for and seeing Sirius, the brightest star in the night sky. Is it the brightest star? Yes and no. For astronomers, the word luminous refers to the intrinsic brightness of a star. To clarify, Sirius is the brightest star in our sky (although not as bright as the planets Jupiter and Venus, of course), but it is not the brightest star in the sky. In other words, it is an ordinary star that only seems very bright because it is relatively close to us: at 8.611 light years.

Sirius is in the constellation of the southern hemisphere of Canis Maior, the Greater Canyon and it looks extraordinarily bright in the Earth's sky. No matter where you live on Earth, follow the three stars of medium brightness in the Orion Belt to locate Sirius.

Sirius is more than 20 times brighter than our Sun, and more than twice as massive.


Many people say they see Sirius with flashes of various colors. It happens when you see Sirius low in the sky. The colors are simply the colors of the ordinary rainbow in the white light of the stars. All starlight is composed of this mixture of colors. However, we notice the bright colors of Sirius more easily because it is much brighter than most stars. The extra thickness of the Earth's atmosphere near the horizon acts like a lens or prism, breaking the light of the stars in the colors of the rainbow. When you see Sirius low in the night sky, you are looking through more atmosphere than when the star is overhead.

If you look, you will notice that Sirius shines less and looks less colorful (more strictly white) when it appears higher in the sky.
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Brighter stars

Is not there a star brighter than Sirius in absolute magnitude?

Of course. Many stars in the dome of the sky are intrinsically brighter than Sirius but appear weaker because they are further away.

It is believed that at least three stars in the constellation of Canis Major are thousands of times brighter than Sirius: Aludra, Wezen and Omicron 2. Although the distances to these distant stars are not known with precision, Aludra and Omicron 2 reside in an estimated from 3,000 light-years distant, and Wezen at about 2,000 light-years. That is in contrast to Sirius' distance of 8.6 light years.

To get a better idea of ​​the true luminosity of a star, astronomers like to list the stars according to their absolute magnitude. The absolute magnitude measures the brightness of the stars as if they were, for example, at an equal distance of 32.6 light years.

It is the brightest star in our sky, but its brightness is mainly due to the fact that it is only 8.6 light-years away.
At 32.6 light years away, our Sun would hardly be visible as a point of light. However, Aludra, Wezen and Omicron 2, 32.6 light-years away, would eclipse Sirius between 100 and 200 times. At 32.6 light years, Sirius would have approximately the same brightness as the star Gemini Castor (at its known distance of 52 light years). Then, if all these stars were equally distant, these super-luminous stars in Canis Major (Aludra, Wezen and Omicron 2) would shine thousands of times more than Sirius. But, as we said at the beginning, as Sirius is closer, the game wins.

Published on: 4/6/19, 4:36 AM