lundi 11 février 2013

The Mysterious Star

(By Mathurin)

VV Cephei A and Jupiter's orbit.
Have you ever heard of VV Cephei? They are strange gigantic stars far out in the universe. VV Cephei A an B orbit each other. VV Cephei itself is also known as HD 208816. It is a mass-exchanging eclipsing binary star system which consists of VV Cephei A, and VV Cephei B. VV Cephei A is a red supergiant while VV Cephei B is a blue main sequence star. VV Cephei is located in the middle of the Constellation Cepheus. The distance from VV Cephei to Earth is unknown because of the size, mass, and luminosity, but it is believed to be about 1,500 and 5,000 light years away from Earth.

VV Cephei is a massive star near to the end of it’s life cycle. Scientists and astronomers think that in 1 million years, VV Cephei will explode into a supernova, releasing a vast quantity of energy, leaving behind a small but a massive black hole or a neutron star.

The two stars orbit each other at an average distance of 25 astronomical units, 
(3,739,946,767.25 km), although, it could be 17 to 34 astronomical units.
1 astronomical unit = 149,597,870.69 km. That is at least the distance from the Sun to Uranus. 

The estimated rotation period is 20.4 years, but it has recently changed. Scientists and astronomers are still trying to figure out the time, but there is a big gap of knowledge.

Sun and VV Cephei A

Cepheus OB2, association of stars, may include VV Cephei as a member.
However, some scientists and astronomers believe that VV Cephei has no relation at all with this group of stars.

VV Cephei has a radius of about 2.5 billion km, which makes it 382,000 times larger than Earth in radius. VV Cephei is 145 billion times larger in surface area than Earth.

VV Cephei is 6 billion years old. Comparing to our home, Earth, Earth is 1.46 billion years younger than VV Cephei.

Binary star system.


Mass-Exchanging Binary Star system
A Mass-Exchanging star happens when a star is taking mass from another star, and also gets physically changed by the shape. It only happens when it is has a Binary system.
A system of two stars orbiting each other around the same point, is called a Binary star system. 

Supergiants are the biggest stars, and the most luminous stars in the Universe.

Constellation Cepheus
Cepheus is a constellation in the northern sky. The name “Cepheus” comes from the King of Ethiopia, Cepheus, in the Greek mythology. It was one of the 48 constellations having being listed by the 2nd century Astronomer, Ptolemy. But it is still one of the 88 modern constellations.

Light Year
A light year is a unit of length equal to just under 10 trillion kilometres. A light year is used to measure distances of stars or another galactic scale.”

A supernova is a stellar explosion that is more energetic than a nova. Supernovas are extremely luminous and can cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months.”

Black Hole
A black hole is a region of space-time where gravity is preventing anything, including light from escaping. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return.”

It is called a black hole because it absorbs all light.

Neutron Star
Neutron stars contain 500,000 times the mass of the Earth in a sphere with a diameter no larger than Brooklyn, United States. Neutron stars are almost entirely made of neutrons.”

Astronomical Units
An astronomical unit is a unit of length that is now 149,597,870,700 meters  exactly, or almost the distance of Earth to Sun. The abbreviations are: AU, au, a.u., or ua.


1 commentaire :

Anonyme a dit…

Vite, j'attends la traduction en français,! je suis tellement fière de toi, mon petit fils !
Ta Mamie