Is sirius a star or planet?

Answer 1

The star Sirius is not a planet or even a single star but is in fact a binary star, or two stars that orbit each other. Together, these two stars are often called The Dog Star, as they are the brightest object in the constellation Canis Major - or The Big Dog.

The stars, named Sirius A and Sirius B, orbit each other about 20 Astronomical Units (the distance from the Sun to the planet Uranus) that takes about 50 years to complete on orbit. Right now, they appear to be moving away from each other and will reach their maximum separation on the year 2019.

At a distance of roughly 8.6 light years, the Sirius binary star system is actually relatively close to us. Sirius A (the larger of the two binary stars) is also extraordinarily bright, about 25 time brighter than our sun. These two factors make Sirius one of the top ten brightest stars in our night sky.

While Sirius A is very large and bright, Sirius B (the smaller of the two binary stars) is significantly smaller than it's companion - about the size of our Earth. But even at it's small size, Sirius B still has nearly the same mass as our Sun. That much mass in such a tiny space means more surface gravity (about twice that of Sirius A) and more heat (about 2.5 times that of Sirius A). Just because it's small, doesn't mean it's not awesome.

Sirius is considered a wintertime star, usually only seen between the months of December and March. It is part of the Winter Triangle asterism along with Betelgeuse and Procyon. So if you're in the Northern Hemisphere and the weather begins to turn cold, take a look into the southern night sky and find Sirius, The Dog Star!

Answer 2

Sirius is a binary star system.

The main star is "Sirius A". It's usually just called Sirius.

Sirius A has a white dwarf companion called "Sirius B".

Sirius B is too faint to be seen without a telescope.

So, the closest star to the star we call Sirius, is Sirius B.

If you consider that binary system as basically "one star", then the nearest bright star to Sirius is Procyon.

There are a few other stars near to Sirius, but they can't be seen with

the "naked eye".

Answer 3

No. Sirius, which includes both Sirius A and Sirius B is the Dog Star. Sirius was called the Dog Star long before it was known to be a binary system. The vast majority of the light from Sirius actually comes from Sirius A. Sirius B on its own is too dim to be seen from Earth without a telescope.

Answer 4

Sirius happens to be the brightest star in our night time sky, but it is not the largest. It is at the right distance from us to appear as brightly as it does.

Answer 5

Sirius has been called the dog star because it is in the constellation Canis Major.