Sirius is so bright that it can even be seen during the day in some areas.
- Sirius is a two star system 8.6 light years from Earth.
- It consists of the main sequence star Sirius A and its small white dwarf companion Sirius B.
- White dwarfs are the core remains of stars that have exhausted their fuel and shed their outer layers.
- Sirius B is the closest white dwarf star to Earth.
- The force of gravity on Sirius B is 350,000 stronger than on Earth, meaning 3 grams of matter (roughly a sugar cube) would weigh 1,000 kilos (2,200 pounds)!
- Sirius A is known as a main sequence star, meaning like the sun it produces energy by fusing hydrogen atoms in its core.
- Sirius is the brightest star in the night sky and the nearest that can be seen without the aid of a telescope.
- Sirius B has a highly elliptical orbit around its larger companion.
- The derivation of the name Sirius is from the ancient Greek word for glowing, the star was also known to ancient Egyptians 4,000 years ago.
Sirius A with its small white dwarf companion Sirius B on the right.
Sirius RadiusSirius A has a radius of 740,000 miles (1.2 million km), which is 71% larger than the radius of the sun, Sirius B has a radius of only 3,650 miles (5,900 km) which makes it slightly smaller than planet Earth!
Sirius MassSirius A has twice the mass of our sun, despite Sirius B being similar in size to Earth it has almost the same mass as the sun, making it an incredibly dense object.
Sirius TemperatureSirius A is estimated to have surface temperatures of around 10,000C (18,000F), almost twice as hot as the sun, Sirius B has surface temperatures of around 25,000C (45,000F), which is almost five times as hot as the sun.
Sirius StatisticsAlso Known As: Alpha Canis Major, the Dog Star
Distance From Earth: 8.6 light years
Constellation: Canis Major
Sirius A Star Type: Class A - Main sequence white star
Sirius B Star Type: White Dwarf
Sirius A Mass: 2.02 x Sun
Sirius B Mass: 0.98 x Sun
Sirius A Luminosity: 25 x Sun
Sirius B Luminosity: 3% of Sun
Sirius A Diameter: Approx 1.5 million miles (2.4 million km) - 171% x Sun
Sirius B Diameter: Approx 7,300 miles (11,800 km) - 92% x Earth
Sirius A Temperature: Approx 10,000C (18,000F)
Sirius B Temperature: Approx 25,000C (45,000F)
Age of System: Approx 240 million years old
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