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Earth And Space > Stars, Planets And Moons > Flashcards

Stars, Planets And Moons Flashcards

0
Q

What are the seven spectral classes?

A

O B A F G K M

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1
Q

Why are stars divided into spectral classes?

A

To give an indication to a stars temperature and the chemical elements in a star

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2
Q

Temp and colour of stars in the spectral class K? Eg.

A

3500 - 5000 K and orange eg. Aldebaran

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3
Q

Temp and colour of stars in the spectral class M? Eg.

A

Less than 3,500 K and red-orange eg. Betelgeuse

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4
Q

Temp and colour of stars in the spectral class G? Eg.

A

5,000 - 6,000 K and yellow eg. Sun, alpha Centauri

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5
Q

Temp and colour of stars in the spectral class F? Eg.

A

6,000 - 7,500 K and yellow-white eg. Canopus and procyon

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6
Q

Temp and colour of stars in the spectral class A? Eg.

A

7,500 - 10,000 K and white eg. Sirius

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7
Q

Temp and colour of stars in the spectral class B? Eg.

A

10,000 - 30,000 K and blue-white eg. Rigel

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8
Q

Temp and colour of stars in the spectral class O? Eg.

A

Greater than 30,000 K and blue-violet eg. Stars of Orion’s Belt

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9
Q

What is a spectrum?

A

When white light is split by a prism. The light becomes spread out by wavelength and as a result you see the colours of the rainbow.

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10
Q

What are absorption lines

A

Absorption lines are dark vertical lines through the spectrum which show which elements and molecules make up the star

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11
Q

What is the narrow band from top left to bottom right on the HR diagram?

A

The main sequence stars

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12
Q

What are main sequence stars?

A

When they fuse hydrogen to helium by nuclear fusion. Most stable part of a stars life cycle

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13
Q

What is the band on the bottom left of the HR diagram?

A

White dwarf stars

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14
Q

What are white dwarf stars?

A

Small, faint, hot very dense stars that are remnants of sun sized stars. Mostly made of carbon and area formed after red giant star loses it’s outer layers.
The remaining cores radiate leftover energy until none is left.

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15
Q

What are the stars above and to the right of the main sequence stars?

A

Supergiants and giants

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16
Q

What are supergiants and giant stars?

A

Older stars that have run out of hydrogen and now fuse heavier elements. These are the brightest stars in the sky

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17
Q

What is he HR (Hertzsprung-Russell) diagram used for?

A

To plot a stars surface temperature and/or spectral class against its luminosity and/or absolute magnitude

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18
Q

Stars with more mass are…

A

Hotter, brighter, bigger and bluer and live shorter because they use their fuel more quickly

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19
Q

Stars with less mass are…

A

Cooler, dimmer, smaller and redder and live longer lives because they use their fuel slower

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20
Q

How do stars look bright?

A

Being close, hot and big

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21
Q

How do stars look dim?

A

Being far away, small and cool

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22
Q

What is a star?

A

A giant luminous ball of very hot burning gas

23
Q

What is a planet?

A

An astronomical object moving in an elliptical orbit around a star

24
Q

What is a solar system?

A

A collection of planets and their moons, including smaller bodies I. The form of asteroids, meteoroids and comets in orbit around a star

25
Q

How many plants in our solar system?

A

8

26
Q

What are the planets in our solar system in order from the sun?

A

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune

27
Q

What are the planets in our solar system made of?

A

Hydrogen, helium, rocks, metals and minerals

28
Q

What holds stars together?

A

Gravity

29
Q

What reaction goes in inside a main sequence star?

A

Nuclear fusion - when the temperature is high enough the fusion of hydrogen to helium starts

30
Q

What is a moon?

A

A body that circles a lager planet or body

31
Q

What is a galaxy?

A

A system of billions of stars, including gas and dust, held together by gravitational attraction

32
Q

How fast does light travel?

A

300,000 kms-1

33
Q

Luminosity

A

Is the total amount of light a star gives off per second

34
Q

Brightness

A

What we see on earth

35
Q

What is magnitude?

A

A measure of brightness of stars

36
Q

What are the two types of magnitude?

A

Absolute magnitude and apparent magnitude

37
Q

Absolute magnitude

A

How bright the star actually is

38
Q

Apparent magnitude

A

Is how bright a star appears to us on earth

39
Q

How are stars born?

A
  1. Giant gas and dust clouds (made up of mostly hydrogen) start to clump together by gravity.
  2. This is often caused by energy waves from nearby exploding supernova. 3.The cloud collapses and begins to rotate and flatten into a disk.
  3. Disk rotates faster and faster pulling more material inwards creating a hot dense core called a protostar
  4. When protostar becomes hot enough, H atoms fuse producing He and energy
  5. A bipolar flow erupts from the protostar and blasts away remaining gas and dust
40
Q

What are the two main sections of a star?

A

A very hot dense core (nuclear fusion)

An outer gaseous shell made of hydrogen and helium which moves heat from the core to the surface

41
Q

What is nuclear fusion?

A

When two or more atomic nuclei join or fuse to form a single heavier nucleus with the release of vast amounts of energy

42
Q

What are red dwarf stars?

A

Cool, dim, main sequence stars that fuse h to he slowly that they never evolve from main sequence into red giants

43
Q

What are black dwarfs?

A

A dead star - after white dwarfs lose their heat energy they become cold, dark black dwarfs

44
Q

What is a brown dwarf?

A

A dim, failed star- one whose mass is too small for nuclear fusion to start so it never becomes a main sequence star

45
Q

What is a neutron star?

A

Remnant of a supernova- very small and dense star composed mostly of tightly packed neutrons

46
Q

What is a pulsar star?

A

A rapidly spinning neutron star that emits energy in pulses

47
Q

What is hydrostatic equilibrium?

A

When a main sequence star has a balance between gravity - pulling atoms towards the centre of the star and the pressure of heat and light radiating out from the centre of the star

48
Q

What is the solar mass of the sun?

A

One solar mass 1Msun

49
Q

Why is knowing the mass of a star important?

A

Determines how bright a star is and how long the star will live

50
Q

What are the 3 main fuels stars fuse?

A

Hydrogen, helium and carbon

51
Q

What is luminosity measured compared with

A

Sun=1Lsun

52
Q

Measurement used for measuring distances around or solar system

A

Astronomical unit - 1AU = 150 million kilometres

53
Q

Measurement used to measure distance between stars

A

Light years - 1ly = 9.5 x 10^12 km or 63240 AU

54
Q

What are red giants

A

Form when sun sized stars run out of hydrogen

55
Q

What are supergiants

A

Form when massive stars run out of hydrogen eventually become supernovae

56
Q

What are blue giants/supergiants

A

Massive blue stars close to running out or have just run out of hydrogen eventually become supernovae

Earth And Space (4 decks)

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