How old is sirius star

The earliest recorded use of the name Sirius dates from the 7th century, when the Greek poet Hesiod mentioned the star in his didactic poem Works and Days. Sirius B compared to Earth. Image: Omnidoom at wikipedia. Sirius has more than 50 names and designations attached to it. In medieval astrolabes from western Europe it is called Alhabor. Sirius was the first star to have its velocity measured.

Sirius is really moving toward the solar system at 7. Along with the bright stars Procyon in Canis Minor and Betelgeuse in Orion constellation , Sirius forms the Winter Triangle , a familiar asterism in the night sky, and easy to spot in winter evenings in the northern hemisphere.

Procyon , Alpha Canis Minoris, is the nearest large neighbouring star to Sirius, located 5. The Voyager 2 spacecraft, which was launched in to study the Jovian planets in our system, will pass within 4. One light year is almost 10 trillion kilometres, or 6 trillion miles. At one point, Sirius was thought to be a member of the Ursa Major Moving Group, an association of stars including most of the brighest stars in Ursa Major constellation , that share a common origin and proper motion through space.

The stars in the Ursa Major Moving Group were roughly million years old and Sirius is about half this age, and therefore too young to belong to the association. Sirius compared to the Sun.

Image: Danilo94 at wikipedia. Twiss at Jodrell Bank in The first photograph of the companion was taken by Dr. Irving W. Lendenblad of the U. Naval Observatory in The colour of Sirius has caused some debate over the centuries, as a number of ancient accounts indicated that the star was red. The Greek astronomer Ptolemy was one of the many who described its appearance as reddish. Seneca, too, had noted that Sirius was of a deeper red colour than Mars.

However, at the same time, there were many observers who described the star as blue or white. Sirius is not the only star affected by this phenomenon, but the changes in colour are more noticeable because the star is so bright and often appears near the horizon. The hieroglyph for Sothis has a star and a triangle. Egyptians based their calendar on the heliacal rising of Sirius in the era of the Middle Kingdom. This would happen just before the summer solstice and the star would be visible before sunrise after being absent from the skies for about 70 days.

The flooding of the Nile brought fertility to the land when the star appeared, and Egyptians associated the goddess with both the inundation, fertility and the new year. It is predicted that Sirius A will completely exhaust its store of hydrogen at its core within a billion years from its formation. It will pass through a red giant stage, then settle down to become a white dwarf similarly to Sirius B.

Sirius B has no internal heating source and will eventually cool as the remaining heat is radiated into space over more than two million years.

Sirius A is about twice as massive as the Sun. Sirius is a binary star consisting of a main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion named Sirius B, which is a spectral type DA2 star.

Since it is so bright and the nearest that can be seen without the aid of a telescope, it has been known to the ancients for a long time, dating back to even 4. The distance between the two stars varies between 8.

The Sirius system is one of the nearest neighbors to Earth, being at a distance of 8. The Sirius system is speculated to be between to million years old. In , Sirius became the first star to have its velocity measured. Sirius B is around Sirius A radiates about 26 times as much energy as our Sun.

Sirius B is the first white dwarf to be discovered, a type of star first understood by Subrahmanyan Chandrasekhar in Sirius B is also the closest white dwarf star to Earth. Sirius A produces energy by fusing hydrogen atoms in its core, much like our Sun. Today, Sirius is nicknamed the "Dog Star" because it is part of the constellation Canis Major, Latin for "the greater dog. The ancients felt that the combination of the sun during the day and the star at night was responsible for the extreme heat during mid-summer.

The star is present in ancient astronomical records of the Greeks, Polynesians and several other cultures. The Egyptians even went so far as to base their calendar on when Sirius was first visible in the eastern sky, shortly before sunrise. According to Space. In , English astronomer Edmond Halley discovered that stars have " proper motion " relative to one another. This means that stars, including Sirius, move across our sky with a predictable angular motion with respect to more-distant stars.

More than years after Halley's finding, in , German astronomer Friedrich Wilhelm Bessel published a scientific note in the Monthly Notices of the Royal Astronomical Society describing how Sirius had been deviating from its predicted movement in the sky since Bessel hypothesized that an unseen companion star affected Sirius' motion. Alvan Graham Clark, a U. That means the light we see today left Polaris in The short answer is that it cannot be dead [meaning cold and emitting no energy] but it could have become a nova or possibly a supernova.

Its estimated age is between and million years, which makes the star considerably younger than the Sun 4. Sirius A has a visual magnitude of Its estimated surface temperature is 9, K.