medium-sized yellow main sequence star (stellar class G)
                diameter - 1,391,980 km(864,938 miles).
                109 times as big as the Earth.
                10 times larger than the planet Jupiter
            The volume
                1,299,400 times bigger than Earth’s
                about 1,300,000 Earths could fit inside the Sun
    distance from Earth: 149,680,000 km (93,026,700 miles )
    diameter 1,391,980 km. (865,121 miles )
    absolute magnitude is +4.83.
    solar mass is 1.99 x 1030 kg.
    5 billion years old
 

At its core, nuclear reactions produce enormous amounts of energy
 
 

 
INTERIOR

    The Core
        tremendously high temperature and pressure.
            temperature roughly 15 million °C.
             nuclear fusion occurs
                 turning four hydrogen nuclei into a single helium nucleus plus a LOT of energy.
                 releases gamma rays (high-energy photons)
                 neutrinos (particles with no charge and almost no mass).

    The Radiative Zone (or radiation zone):
        next layer out emits radiation
        diffuses outwards.
        Surface temperature range 5,500 °C - 6000°C
        photons of radiation take millions of years to pass through the radiative zone

    The Convective Zone
        next layer
        photons continue to make their way outwards via convection(towards lower temperature and pressure).
        temperature ranges - one million °C to 6,000 °C.

 
ATMOSPHERE

    The Photosphere
         lower atmosphere of the Sun
         part that we see
         emits light at visible wavelengths
          about 300 miles (500km) thick.
          temperature is about 5,500 °C.

 The Chromosphere \
        reddish layer is an area of rising temperatures.
        temperature ranges from 6,000 °C (at lower altitudes) to 50,000 °C (at higher altitudes).
         a few thousand miles (or kilometers) thick.
        visible during solar eclipses
        when the moon blocks the Photosphere
        appears red
             hydrogen atoms in an excite state
            and emit radiation near the red part of the visible spectrum

 The Corona
        outer layer.
        extends for millions of miles
         temperatures one million °C.
        Holes
            occur where the Sun's magnetic field loops out into space.
                 - may be the source of the solar wind,
                    a stream of energetic particles
 

    Solar Rotation
        rotates around an axis  perpendicular to the plane of the eliptical
         rotational axis is tilted by 7.25°
        rotates -counterclockwise direction (when viewed from the north),
        rotation period varies with latitude.
        Equatorial regions rotate faster than polar regions.

   FEATURES
    Sunspots
         -relatively cool, dark patches
            only last for one to two weeks
            number of sunspots follows an 11 year cycle
            peak in the middle of 2000
            many shapes and sizes;
            appear in groups.
                much bigger than Earth over 10 times the diameter

    Solar Flares
          magnetic storm on the Sun
            very bright spot
         gaseous surface eruption. and gases and are
        release huge amounts of high-energy particles
        tremendously hot (from 3.6 million to 24 million °F).
             ejected thousands of miles
             first observed - 1859 by Lord Richard C. Carrington. –
             "two patches of intensely bright and white light" near a huge group of sunspots.
       recently discovered cause sunquakes.
                violent seismic events on the Sun.

    Solar Wind
        a continuous stream of ions
    emitted where the Sun's magnetic field loops out into space
        called coronal holes.
     coronal holes are black areas.
            can last for months or years.
        4.5 days to reach Earth;
         velocity of about 400 km/sec(250 miles/sec).
        solar wind blows in a pinwheel pattern through the solar system.
            affects the entire Solar System
            buffeting comets' tails away from the Sun,
                causing auroras on Earth
                    the disruption of electronic communications on Earth, pushing spacecraft around, etc.

 SOLAR PROMINENCE
        (filament) is an arc of gas erupts from the surface
        Prominences can loop hundreds of thousands of miles into space.
                 held above the Sun's surface by strong magnetic fields
                can last for many months.
,                most prominences will erupt, spewing enormous amounts of material into space.

CORONAL MASS EJECTION
    (abbreviated CME's)
    huge, balloon-shaped plasma bursts
    move along the Sun's magnetic field line
    increase in temperature tens of millions of degrees.
    release up to 220 billion pounds (100 billion kg) of plasma.
        disrupt Earth's satellites.
        happen independently, but are sometimes associated with solar flares.

    Solar Eclipses
        when the moon blocks our view of the sun.
        Moon is exactly between the Sun and the Earth.