The Properties of Our Sun

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Slide 30

The Aurora

The solar wind passes out through the Solar System.

Consists of electrons, protons and other charged particles stripped from the Sun’s surface.

Interaction with planetary magnetic fields gives rise to the aurora.

Slide 31

The Active Sun

Solar luminosity is nearly constant.

Very slight fluctuations.

11-year cycle of activity.

Slide 32

Solar Cycle

Increase in Coronal holes

Increase in solar wind activity

- Coronal Mass Ejections

Increase in Auroral displays on Earth

Increase in disruptions on and around Earth.

Slide 33

Sunspots

11-year sunspot cycle.

Center – Umbra: 4500 K

Edge – Penumbra: 5500 K

Photosphere: 5800 K

Slide 34

Can see that Sun doesn’t rotate as a solid body?

Equator rotates faster.

This differential rotation leads to complications in the Solar magnetic field.

Slide 35

Magnetic fields and Sunspots

At kinks, disruption in convection cells.

Sunspots form.

Slide 36

Magnetic fields and Sunspots

Sunspots come in pairs.

Opposite orientation in North and South.

Every other cycle the magnetic fields switch.

Slide 37

Sunspot Numbers

Slide 38

Active Regions

Areas around sunspots give rise to the prominences