Star | The Schools' Observatory

Star Formation

Stars form in huge clouds of gas and dust called nebulae. These areas of space are sometimes known as 'stellar nurseries' or 'star forming regions'.

A wide column of red/brown cloud and gas rises upwards in the middle, splitting off into three separate vertical branches. The background is dark blue and black, though brighter around the edges of the branches. Throughout the image, there are bright red and white dots of stars scattered throughout. Three particularly large red stars are visible in the upper left quadrant of the image. — A small region of the Eagle Nebula. This structure has been named the 'Pillars of Creation'.

Stellar Evolution

All stars form in nebulae, huge clouds of gas and dust.

Though they shine for thousands of years, stars do not last forever. The changes that occur in a star over time and the final stage of its life depends on a star's size.

A diagram showing the stages in the life cycle of a star. "Creation" is at the top, also labelled "Stellar Nebula" along with a graphic of a pink swirly cloud. Two arrows point left and right with the label "Main Sequence". On the left is "High Mass Star", a blue circle, and arrows lead to the next stages which are "Red Supergiant", "Supernova", "Neutron Star" and "Black Hole". The right arrow leads to a "Low Mass Star", a yellow circle. Arrows then point to the next stages.

Star Clusters

Star clusters are groups of stars which are held together by gravity.

There are two types of star clusters: globular clusters and open clusters.

Variable Stars

Stellar Classification

Astronomers began to categorise stars, based on their mass and temperature, hundreds of years ago. As scientists have learned more about stars, this classification scheme has had to evolve.

An image showing seven spheres of increasing size. These are labelled, from left to right, "M", "K", "G", "F", "A", "B", and "O". "M" is red in colour. "K" is orange. "G" is yellow. "F" is yellow-white. "A" is white. "B" is white with hints of blue. "O" is white in the middle that fades to blue around the edges. — Depiction of different star classes

Stars

Stars are massive, glowing balls of extremely hot gas (called plasma) in space. The Sun is our closest star.

The sun against a black background. It is a dark orange sphere with some brighter yellow patches as well as some dark brown/black patches. — The Sun

Claudius Ptolemy

Occupation

Mathematician, Astronomer, Geographer

Year born

100 AD

Research Areas

Movements of planets and stars, Cartography

A painting of Claudius Ptolemy. He is sat down and holding a gold armillary sphere model in one hand.

This work by Joos van Ghent and Pedro Berruguete (1476) is licensed under Creative Commons Zero v1.0 Universal

Cecilia Payne Gaposchkin

Occupation

Astronomer

Year born

1900

Research Areas

Stars, Spectroscopy

A black and white photograph of Cecil Payne-Gaposchkin. She is standing and looking to one side.

Classify a Star

Have you ever wondered why stars look different colours? What do these colours mean? How do we know what stars are made of? Explore these questions with our classify a star activity.

Read more about Classify a Star

What is a nebula?

Read more about What is a nebula?

Occupation

Year born

Research Areas

Occupation

Year born

Research Areas

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