You will not be able see blue stars without specialized equipment, and you won’t even be able distinguish the outer layers of a star with an ordinary telescope. You can’t see muchin the night skies without very specialized equipment. Anatoliy_gleb/Shutterstock When you gaze up into the sky at night, you are only seeing a tiny sample of the different types of stars in the universe. Each of these cosmic powerhouses is powered by nuclear-fusion at its core. They come in different colors, sizes and stages.
These differences aren’t just for display; the mass, age and temperature of a star determines how it goes through its lifecycle.
1. Red supergiant stars
Nazarii Neshcherenskyi/Getty Images
The largest stars of the universe are those that reach up to 200-300 times the mass of the Sun. The outward pressure of nuclear fusion at the core balances the gravitational pull inward until all the fuel in the star is used up.
Even the most massive of stars could end up as black holes. Red supergiants like Betelgeuse shine brightly in the Milky Way.
2. Massive Stars (19659004): More massive stars are able to burn through all fusion reactions more quickly than their smaller counterparts. This category includes O-type and B-types stars, which are blazingly blue stars with temperatures on their surfaces that are far higher than the Sun.
A massive star can collapse into a black-hole or a neutron.
3. Main Sequence stars
The majority of stars live their entire lives in the main sequence. In this region, the outward pressure of light from nuclear fusion at the core perfectly balances inward gravitation. Here, young stars form in a molecular storm.
4. Red Giant Stars (19659007) When stars with low masses run out of the hydrogen they contain in their cores and swell, they become red giants. The outer layers of the stars expand as fusion reactions move outward. The white dwarf can be left behind at this stage, which may lead to the formation of a planetary-sized nebula.
5. White Dwarfs (19459038) White dwarf. Nazarii Neshcherenskyi/Getty Images
The white dwarf is a remnant core from a sun-like star after its outer layers have drifted into space. It shines without fusion.
It cools down over billions of year into a dark dwarf. However, the universe hasn’t aged enough to have any.
6. Neutron Stars
Neutron star. Nazarii Neshcherenskyi/Getty Images
The inward crushing force of a collapsed massive star is so strong that it crushes electrons and protons into neutrons. The mass of these objects is greater than that of the Sun in a small sphere measuring only 12.4 miles ( 20 km). Sometimes they are found within a binary system of stars with another star.
7. Brown Dwarfs (19459038) Brown dwarf. Nazarii Neshcherenskyi/Getty Images
Brown dwarfs are sometimes called “failed star” because they have insufficient mass to initiate the same fusion reactions as a real star. Even after millions of years, they can glow in faint visible light.
8. Pre-Main Sequence Stars (pre-19659010) In regions of active star formation, young stars like T Tauri have not yet achieved the main sequence. Although it still looks like main sequence stars, the hydrogen fusion has not yet begun.
9. Binary and double stars
Many of the stars in a binary or double system orbit a central mass. The pairings may be stable, or they can lead to massive mass transfers.
10. The term evolved stars
is used to describe stars at later stages of their life, from bright giants through red giants, and on up to supergiants after they have exhausted the core hydrogen. The path they take depends on the original mass of their stellar core, and determines whether or not they become white dwarfs. This article was created using AI, and then fact-checked by HowStuffWorks editors.