Login | Sign Up | Print Page
Enchanted Learning Logo Enchanted Learning Logo
Home Site Index What's New Free Sample Pages Login Subscribe
Follow us on Twitter Like us on Facebook
Advertisement.

EnchantedLearning.com is a user-supported site.

Site members have full access to an ad-free, print-friendly version of the site.

Click here to learn more.

title image

Birth of Stars

AstronomyScienceStars (Astronomy)
Astronomy Table of Contents►
Astronomy Site Index►
Share this page:
Share on TwitterShare on FacebookShare on PinterestPrint this Page
Table of Contents
  • Accretion disk
  • A central core and a protoplanetary disk
  • Protostar
  • A newborn star
  • Life span

Accretion disk

The eagle nebula

The Eagle nebula, a stellar nursery illuminated by ultraviolet light which is emitted from the newborn stars.

Stars are formed in nebulae, interstellar clouds of dust and gas (mostly hydrogen). These stellar nurseries are abundant in the arms of spiral galaxies.

An accretion disk

An accretion disk

In these stellar nurseries, dense parts of these clouds undergo gravitational collapse and compress to form a rotating gas globule.

The birth of a star - part 1

The globule is cooled by emitting radio waves and infrared radiation. It is compressed by gravitational forces and also by shock waves of pressure from supernova or the hot gas released from nearby bright stars. These forces cause the roughly-spherical globule to collapse and rotate. The process of collapse takes from between 10,000 to 1,000,000 years.

A central core and a protoplanetary disk

As the collapse proceeds, the temperature and pressure within the globule increases, as the atoms are in closer proximity. Also, the globule rotates faster and faster. This spinning action causes an increase in centrifugal forces (a radial force on spinning objects) that causes the globule to have a central core and a surrounding flattened disk of dust (called a protoplanetary disk or accretion disk). The central core becomes the star; the protoplanetary disk may eventually coalesce into orbiting planets, asteroids, etc.

The birth of a star - part 2

Protostar

The contracting cloud heats up due to friction and forms a glowing protostar; this stage lasts for roughly 50 million years. If there is enough material in the protostar, the gravitational collapse and the heating continue.

If there is not enough material in the protostar, one possible outcome is a brown dwarf (a large, not-very-luminous celestial body having a mass between 1028 kg and 84 x 1028 kg).

A newborn star

The sun

Our Sun

When a temperature of about 27,000,000°F is reached, nuclear fusion begins. This is the nuclear reaction in which hydrogen atoms are converted to helium atoms plus energy. This energy (radiation) production prevents further contraction of the star.

Young stars emit jets of intense radiation that heat the surrounding matter to the point at which it glows brightly. These narrowly-focused jets can be trillions of miles long and can travel at 500,000 miles per hour. These jets may be focused by the star’s magnetic field.

The protostar is now a stable main sequence star which will remain in this state for about 10 billion years. After that, the hydrogen fuel is depleted and the star begins to die.

Life span

The most massive stars have the shortest lives. Stars that are 25 to 50 times that of the Sun live for only a few million years. Stars like our Sun live for about 10 billion years. Stars less massive than the Sun have even longer life spans.

Other Links:
Estimated Grade Level
Our subscribers' grade-level estimate for this page:
5th - 6th
You Might Also Like:
Star Death - Astronomy
Activities: The Stars
The Life Cycle of a Star - Astronomy
Why Do Stars Twinkle?
Stars Cloze Activity
Star Life Cycle
Birth of Stars
Death of Stars
Death of Sun-Like Stars
Death of Huge Stars
Death of Giant Stars
Stars
The Stars
Lifecycle
Birth
Death
Nuclear Fusion
Star Types
Brightest Stars
Closest Stars
Galaxies
Nebulae
Other Solar Systems
Major Stars
Constellations
The Zodiac
Why Stars Twinkle
Activities & Links
Zoom Astronomy
— All About Astronomy —
Table of Contents
Index
More on Astronomy
Stars
Our Solar System
Astronomy Glossary
Hall of Astronomers
Printables, Worksheets, and Activities
Advertisement.
▾ See more
Site Overview
What's New
Enchanted Learning Home
Monthly Activity Calendar
Books to Print
Site Index
Enchanted Blog
K-3
Crafts
K-3 Themes
Little Explorers
Picture Dictionary
PreK/K Activities
Rebus Rhymes
Stories
Writing
Cloze Activities
Essay Topics
Newspaper
Writing Activities
Parts of Speech
Fiction
The Test of Time
Biology
Animal Printouts
Biology Label Printouts
Biomes
Birds
Butterflies
Dinosaurs
Biology Continued
Food Chain
Human Anatomy
Mammals
Plants
Rainforests
Sharks
Whales
Physical Sciences: K-12
Astronomy
The Earth
Geology
Hurricanes
Landforms
Oceans
Tsunami
Volcano
Languages
Dutch
French
German
Italian
Japanese (Romaji)
Portuguese
Spanish
Swedish
Geography/History
Explorers
Flags
Geography
Inventors
US History
Other Topics
Arts and Artists
Calendars
College Finder
Crafts
Graphic Organizers
Label Me! Printouts
Math
Music
Word Wheels
Copyright © 1999-2025 EnchantedLearning.com
How to cite a web page
-
Our Privacy Policy
-
Site Index
-
Contact Us
-
About Us
-
Subscribe
Advertisement.
Advertisement.