Star Classification Flashcards

Questions and Answers

What is a dwarf star?

A large star with high luminosity

A star that is the same size as the sun

A small star up to 20 times larger than our sun (correct)

A star that has no nuclear fusion

What type of star is the Sun?

Blue giant

Red giant

Yellow dwarf (correct)

Neutron star

What temperature characterizes a red dwarf?

Under about 4,000 K

What is a red giant?

A star whose diameter is about 100 times bigger and cooler than it originally was. Signup and view all the answers

What characterizes a blue giant?

A huge, very hot star that burns helium. Signup and view all the answers

What happens when supergiants die?

They explode in supernovae Signup and view all the answers

What is a white dwarf?

A small, very dense, hot star made mostly of carbon. Signup and view all the answers

What is a brown dwarf?

A 'star' whose mass is too small for nuclear fusion. Signup and view all the answers

A pulsar is a rapidly spinning ______ star that emits energy in pulses.

neutron Signup and view all the answers

What is a binary star?

A system of two stars that rotate around a common center of mass. Signup and view all the answers

What is an eclipsing binary?

Two close stars that appear to be a single star varying in brightness. Signup and view all the answers

What characterizes X-ray binary stars?

One of the stars is a collapsed object like a white dwarf or neutron star. Signup and view all the answers

What are Cepheid variable stars known for?

Regularly pulsating in size and changing in brightness. Signup and view all the answers

What is a Mira variable star?

A variable star that cycles brightness and size over a long time period. Signup and view all the answers

Study Notes

Dwarf Stars

Dwarf stars are small stars, ranging up to 20 times the size of the Sun and up to 20,000 times its brightness.
The Sun qualifies as a dwarf star.

Yellow Dwarf

Yellow dwarfs are small, main sequence stars.
The Sun is categorized as a yellow dwarf.

Red Dwarf

Red dwarfs are small, cool stars with surface temperatures under 4,000 K.
These stars are the most common type in the universe; an example is Proxima Centauri.

Giant and Supergiant Stars

Giant and supergiant stars are characterized as large, older stars.

Red Giant

A red giant is significantly larger in diameter, around 100 times its original size, and cooler (surface temperature under 6,500 K).
Betelgeuse is a notable red giant, about 20 times more massive than the Sun and roughly 14,000 times brighter.

Blue Giant

Blue giants are massive, hot stars that burn helium and are post-main sequence.

Supergiant

Supergiants are the largest known stars, some nearly as expansive as the solar system.
Betelgeuse and Rigel are examples; they are rare and may end their life cycle as black holes after a supernova.

White Dwarf

White dwarfs are small, dense stars primarily composed of carbon, remnants of red giants after they shed outer layers.
They are around the size of Earth but significantly heavier and will eventually cool into black dwarfs. The Sun will evolve into a white dwarf.

Brown Dwarf

Brown dwarfs have insufficient mass for nuclear fusion; they are dim and have a mass range of 10^28 kg to 8.4 x 10^28 kg.

Neutron Star

Neutron stars are incredibly dense, composed mainly of neutrons, with diameters of 5-10 miles (5-16 km) and extreme densities of approximately 10^15 gm/cm³.

Pulsar

Pulsars are rapidly spinning neutron stars emitting radiation in pulses.

Double Star

A double star system consists of two stars appearing close to each other; some are true binaries while others are optical doubles.

Binary Star

A binary star system involves two stars orbiting their common center of mass (barycenter); about half of all stars pair with at least one other star.

Eclipsing Binary

Eclipsing binaries are two stars that periodically obscure or enhance each other's brightness, viewed edge-on from Earth.

X-ray Binary Star

X-ray binaries contain a collapsed star (like a white dwarf or neutron star) paired with a normal star; X-rays are produced as matter is drawn from the latter towards the collapsed object.

Cepheid Variable Stars

Cepheid variables regularly change in size and brightness; as they expand, brightness decreases, and vice versa.
Examples include Polaris and Delta Cephei.

Mira Variable Star

Mira variables undergo prominent changes in brightness and size over long periods, sometimes varying by as much as 6 to 8 magnitudes.
Named after the star Mira, which had its fluctuations discovered in 1596.

Description

Explore the fascinating world of star classification with these flashcards. Learn about different types of dwarf stars, including yellow and red dwarfs, and their characteristics. Perfect for astronomy enthusiasts or students looking to deepen their knowledge of stellar types.