10 Solar Astronomy Flashcards

1
Q

How can you safely observe the Sun?

A
  • Pinhole projection
  • H-alpha filter
  • Telescopic projection
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2
Q

What are sunspots?

A

Sunspots are cooler areas of the Photosphere where the Sun’s magnetic field rises from below the Sun’s surface and the magnetic regions poke through. They are darker in colour as they are expending less energy and have a lower temperature

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3
Q

What is the average temperature of a Sunspot?

A

Umbra is ~3800K

Penumbra is ~5600K

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4
Q

How can you calculate solar rotation period?

A

If the difference in longitude (ΔL) of a sunspot occurs in a time interval, then rotation period (T) can be calculated by:
T . . 360°
—- = ——
Δt . . ΔL

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5
Q

What is the earliest Nuclear Fusion?

A

The earliest Nuclear Fusion is when hydrogen (H) nuclei fuse into Helium (He) nuclei.

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6
Q

Why can Nuclear Fusion only happen in the Sun’s core?

A

The temperature has to be high enough to overcome the mutual electrostatic repulsion of the positively-charged nuclei

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7
Q

What is the chain of reaction that happens in the Sun?

A

The Proton-Proton or Deuterium-Deuterium chain

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8
Q

What happens in each stage in the proton-proton chain?

A

At each stage in the chain, mass (m) is lost and converted into energy (E). This is in accordance with Einstein’s equation E=mc², where c is the speed of light

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9
Q

How much mass does the Sun lose?

A

The Sun loses 4 million tonnes of mass every second, this is insignificant as the Sun’s total mass is 2.0 × 10²⁷ tonnes

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10
Q

What is the zone above the Sun’s core?

A

Radiative zone

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11
Q

What happens in the radiative zone?

A

This zone is where the energy in the form of photons (gamma-radiation) is transferred in a random manner due to the scattering of photons by electrons outwards

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12
Q

What is the zone outside the radiative zone?

A

The convection zone

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13
Q

How thick is the convection zone?

A

~200 000 km

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14
Q

What happens in the convection zone?

A

The convection zone is where the thermal energy is transported to the photosphere by rising convection currents of hot plasma.

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15
Q

What is at the top of the convection zone?

A

The photosphere

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16
Q

How hot is the photosphere?

A

The photosphere is ~2 million K at the base. At the visible part of the photosphere, the temperature is 5800 K

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17
Q

How thick is the photosphere?

A

100 km

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18
Q

How does the Sun radiate energy?

A

The Sun radiates energy in the form of visible light but also to a lesser extent of infra-red, ultra-violet and X-Radiation

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19
Q

What are the parts of the Sun’s atmosphere?

A

The chromosphere and corona

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20
Q

How thick is the chromosphere?

A

2000 km thick

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21
Q

How hot is the chromosphere?

A

400 K - 100 000 K at the top

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22
Q

How hot is the corona?

A

2 million K

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23
Q

How far can the corona extend?

A

The corona can extend outwards for millions of km into space

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24
Q

What is ‘slow’ solar wind?

A

An outflow of charged particles (mostly protons and electrons)

25
Q

Where does ‘slow’ solar wind come from?

A

The Corona

26
Q

What is the speed of ‘slow’ solar wind?

A

~400 km/s

27
Q

Where does ‘fast’ solar wind originate from?

A

Coronal holes

28
Q

What is ‘fast’ solar wind associated with?

A

Coronal mass ejections and Solar Flares

29
Q

What is solar wind responsible for?

A

Solar wind is responsible for aurora and the creation of cometary tails

30
Q

What is the Butterfly Diagram?

A

The butterfly diagram is a diagram that shows the solar cycle of sunspots. The cycle begins with a few spots at mid latitude. The numbers of sunspots fall and rises, and they drift towards the solar equator

31
Q

How long does the solar cycle last?

A

11 years

32
Q

What is a Type II Supernova?

A

A Red Supergiant collapses

33
Q

What is a Type Ia Supernova?

A

A Type Ia Supernova occurs when Red Giant star is in a binary system with a white dwarf. Over time, the white dwarf will gravitationally steal matter from the Red Giant, resulting in the increase of mass. It will surpass the Chandrasekhar limit and the electron degeneracy pressure will be insignificant in preventing the collapse, resulting in a supernova

34
Q

What stage of a star does a planetary nebula represent?

A

Death

35
Q

What is Fast solar wind?

A

A build up of of magnetic energy which is released from a sunspot

36
Q

What is slow solar wind?

A

Particles that are emitted from all over the Sun.
They are slowed by the magnetic fields of the Sun
They are mostly charged protons and electrons

37
Q

When is there more fast solar wind?

A

During the middle of a Sunspot cycle where there are the most amount of Sunspots

38
Q

Why does Nuclear fusion only take place in the Sun’s core?

A

The particles need to be hot enough to withstand the electric repulsive forces. They have to hit each other fast so they need to be at very high pressure (15 Million Kelvin)

39
Q

What are sunspots?

A

Sunspots are black spots on the surface of the Sun that are formed where the the magnetic field leaves the surface. It is a cool area where no convection occurs

40
Q

What prevents the ionising rays from reaching the surface of the Earth?

A

Magnetosphere

41
Q

What is the equation that tells you how to find longitude in the UK?

A

Local Mean Time - Mean Solar Time In Greenwich
_______________________________________
. . . . . . . . . . . . . . . . . . . . . . . 4
=Degrees of Longitude to the East

42
Q

What is the First Umbral Contact for a solar eclipse?

A

The First Umbral Contact is when the Moon starts to cover the Sun

43
Q

What is the Second Umbral Contact for a solar eclipse?

A

The second Umbral contact is when the Moon has just finished covering the Sun

44
Q

What is the Third Umbral contact for a solar eclipse?

A

The Moon is on the cusp of leaving the Umbra of the Sun

45
Q

What is the Fourth Umbral Contact for a solar eclipse?

A

The fourth Umbral Contact is when the Moon has just left the Sun

46
Q

What is an Annular solar eclipse?

A

When the Moon is too small to fully cover the Sun so a ring of light surround the Sun

47
Q

Why does an Annular Solar eclipse occur?

A

An Annual Solar Eclipse occurs when the Moon’s orbit is in an apogee and the the Moon appears to small to cover the entire Sun compared to normal eclipses.

48
Q

What is an accretion disk?

A

An accretion disk consists of hot, swirling gas captured by a white dwarf ( or neutron star or black hole ) from a binary companion star.

49
Q

When can white dwarf supernova occur?

A

A white dwarf supernova can occur only in a binary system, and all such events are thought to have the same luminosity.

50
Q

What are the Sun’s internal divisions in order?

A

Photosphere
Convective zone
Radiative zone
Core

51
Q

How does a H-alpha filter make the observation of the Sun safe?

A

A H-alpha filter makes the observation of the Sun safe as the intensity of light received from the Sun is reduced

52
Q

Where does the Sun rotate faster?

A

The Sun rotates faster at the equator then the poles

53
Q

How hot is the Corona?

A

2 million K

54
Q

How hot is the Core of the Sun?

A

15 million K

55
Q

How hot is the photosphere?

A

5800 K

56
Q

How hot is the top of the Chromosphere?

A

100 000 K

57
Q

How hot is a typical Sunspot Umbra?

A

3800 K

58
Q

How hot is a typical Sunspot Penumbra?

A

5600 K