Space may seem empty, but actually it is filled with thinly spread gas and dust. This gas and dust is called interstellar medium. The atoms of gas are mostly hydrogen (H2), and the gas atoms are typically about a centimeter apart. The dust is mostly microscopic grains and comprises only a few percent of the matter between stars. The dust is mostly carbon and silicon. In some places, this interstellar medium is collected into a big cloud of dust and gas known as a nebula. This is the birthplace of stars because the gas and dust is what makes up a star. In fact, our sun was probably born in a nebula nearly 5 billion years ago.

A Neutron star is formed from the remains of the high-mass stars; The cycle will restart all over again.

Gemini represents the twins Castor and Polydeuces (Pollux is the Latin form of his name); they were known to the Greeks as the Dioscuri, literally meaning ‘sons of Zeus’. However, mythologists disputed whether both really were sons of Zeus, because of the unusual circumstances of their birth. Their mother was Leda, Queen of Sparta, whom Zeus visited one day in the form of a swan (now represented by the constellation Cygnus).

This is the system the Castor star is in.
http://www.absoluteastronomy.com/topics/Castor_(star)
Parameter
Star Component
Aa
Ab
Ba
Bb
Ca
Cb
Spectral type
Stellar classification
In astronomy, stellar classification is a classification of stars based on its spectral characteristics. The spectral class of a star, is a designation of a class to a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective...
A1 V
Unknown (probably M5 V)
A2 Vm
M2 V
M0.5 Ve
M0.5 Ve
Mass (M☉
Solar mass
The solar mass , , is a standard way to express mass in astronomy, used to describe the masses of other stars and galaxies. It is equal to the mass of the Sun, about two nonillion kilograms or about 332,950 times the mass of the Earth or 1,048 times the mass of Jupiter.The solar mass can be...)
2.15
0.4–0.6
1.7
0.4–0.6
0.62
0.57
Radius (R☉
Solar radius
In astronomy, the solar radius is a unit of length used to express the size of stars. It is equal to the current radius of the Sun. Its value is: ....)
2.3
?
1.6
?
0.76
0.68

The Castor star is about 2.3 times the mass of the sun.

The Castor star is twice the size in diameter if the sun.

The Castor sizi is 6 times the luminostity compared to the sun.

It is 10,300/8,840K.("K." is used to determine the temperature."K" stands for Kelvin.)

It is a light quite blue.

It is 52 light years away from the sun.

These pictures are of the star Castor. The stars are apparently eternal, shining steadily night after night without change. Based upon their energy consumption (that is, brightness) and their available fuel supply (their mass), we deduce that stars can live for billions, even trillions of years.