What is Sirius?

Answer 1

Sirius is a binary system, that appears as a single star from Earth

• Sirius A has an absolute magnitude of 1.42
• Sirius A has an apparent magnitude of -1.46
• Sirius B has an absolute magnitude of 11.18
• Sirius B has an apparent magnitude of 8.3

See related question for the difference between absolute and apparent.

Answer 2

Sirius is actually two stars, also known as a binary star system. The main star, Sirius A, is a white main sequence star (Class A1V) larger and brighter than our sun. The secondary star, Sirius B is a white dwarf, the small, dense remnant of a dead star.

Answer 3

Earlier astronomers wrote about Sirius being red or red hue. Clearly Sirius is not red or even slightly red, so some controversy exists about what the early astronomers were observing.

It was first thought that Sirius might have changed over time, but given the timescale of only a few thousand years, this was dismissed.

The most plausible explanation is that they were viewing the star near the horizon, giving the impression of being red or another star entirely.

See related link for more information.

Answer 4

Sirius is the brightest star in the night sky and is located in the constellation Canis Major. It is a binary star system, consisting of a main-sequence star, Sirius A, and a white dwarf, Sirius B. Sirius has been observed and studied for centuries and holds cultural significance in various civilizations.

Answer 5

Sirius is actually a binary star system.

Sirius A has a spectral type of A1V and is a star on the main sequence.

Sirius B is a white dwarf. Yep

Answer 6

Sirius is a binary system.

Sirius A has a spectral class of A1V [See related questions]
Sirius B has a spectral class of DA2 meaning it is a white dwarf.

Answer 7

It's almost completely hydrogen and helium.