Our Sun

Our Sun – The Abnormal StarFact – our sun is a star

• Average in size (thus yellow in appearance)

• Middle Age for a star

But it is not part of a multiple star cluster!

Chromosphere

Anatomy of the Sun

Corona - 1,700,000° C

Chromosphere - 27,800° C

Convective Zone

Radiative Zone

The CORE – 15,000,000° K

Anatomy of the SunTo convert °C to °F °F = (°C X 9/5) + 32

Photosphere - 6,000° C

REGIONINNER RADIUS TEMPERATURE DENSITY DEFINING

PROPERTIES(km) (K) (kg/m3)

Core 0  15,000,000 150,000 Energy generated by nuclear fusion

Radiation zone 200,000  7,000,000 15,000 Energy transported by electromagnetic radiation

Convection zone 500,000  2,000,000 150 Energy carried by convection

Photosphere 696,000* 5800 2  10-4Electromagnetic radiation can escape—the part of

the Sun we see

Chromosphere 696,500* 4500 5  10-6 Cool lower atmosphere

Transition zone 698,000* 8000 2  10-10 Rapid temperature increase

Corona 706,000  1,000,000 10-12 Hot, low-density upper atmosphere

Solar wind 10,000,000  2,000,000 10-23

Solar material escapes into space and flows

outward through the solar system

TABLE 16.1 The Standard Solar Model

CoreIn solar astronomy,

the innermost part of the Sun is where

energy is generated by nuclear reactions.

An interior layer of the Sun, lying

between the core and the convection zone, where energy travels outward by radiation.

Radiative Zone

The layer of the Sun between the radiative

zone and the photosphere where

energy travels outward by convection.

Convective Zone

PhotosphereThe visible surface of the Sun.

It is a layer of gas that is heated enough to shine.

It is the layer from which the light we actually see (with

the human eye) is emitted. It is also the layer

astronomer’s refer to as the Sun’s “surface.”

Circulation in the Sun

ChromosphereThe layer above the photosphere and beneath the transition region and the corona. The

chromosphere is hotter than the photosphere but not as hot as

the corona.

The outer layer of the sun. It looks like a halo

and is visible during eclipses or from special

telescopes. Extends about a million miles

out into space.

Corona

Radiation

Energy created in the core radiates out through radiation zone Next, it moves from the core through the convection zoneFinally, it exits the sun’s atmosphere

AKA – Electromagnetic Radiation

Nuclear Fusion The process by which multiple like-charged

atomic nuclei join together to form a heavier nucleus.

Nuclear Fusion The process by which multiple like-charged

atomic nuclei join together to form a heavier nucleus.

The proton–proton chain reaction

dominates in stars the size of the Sun or

smaller.

In this reaction, hydrogen fuses to create helium and

energy.

At the current rate of fusion, the Sun should

continue to burn for another 5 billion years.

Features of the Sun

Sunspots

Size comparison of Earth to a sunspot

A temporary disturbed area in the solar photosphere

- Cooler than the surrounding areas- Appear as dark spots- Made from strong magnetic fields. - Usually occur in pairs or groups of opposite polarity that move together across the surface of the sun. - Occur in an 11-year cycle

11-Year Solar Cycle

Loops of cool plasma that link different parts of

sunspots.

Prominences

A solar prominence is vast and awesome in

size in contrast to

our little Earth. But

the Earth is so far from the sun that

these prominences

pose no danger. Image via NASA

Prominences

Huge, high-arching plasma columns

May occur when prominences loop

together, or sunspots move together. This

produces a very violent eruption on the surface of the sun called a solar

flare.

SolarFlares

CME’s

Coronal Mass EjectionsLarge amounts of electrically charged gas suddenly ejected from the Sun’s corona.

CME’s

During periods of sunspot maximum, CME’s can

occur two or three times each day.

http://www.mnn.com/earth-matters/space/stories/stunning-coronal-mass-ejection-erupts-from-sun-photo

CME’s appear as a halo around the sun.They cause magnetic storms, which damage satellites, interfere with radio

signals, and can damage electrical grids.

CME’s

CME’s

CME’s – The Impact to Earth

Solar Wind

The outflow of charged

particles from the Sun’s corona.

Solar Winds and EarthWhen CME’s, in the form of a solar

wind, interact with our magnetosphere, they can produce the light show called an Aurora.The charged particles carried by the solar wind generate electric

currents at the poles. These currents ionize gases in the

atmosphere, which produce the lights.

SolarStorm

Geomagnetic storm produced by solar flares, CME’s or coronal holes. Can affect

satellites, communication and navigation systems, and

electrical systems.

The distance light travels in one year in a vacuum

Light travels at 300,000 km/sec or 186,000 mi/sec 1 light year = 9,460,730,472,580.8 km

(That is approximately 9.5 trillion kilometers or 5.9 trillion miles!!!)

The distance from the Earth to the Sun is approximately 150,000,000 kilometers, or 93,000,000 miles.

So then, how many light years is itfrom the Earth to the Sun?

The Light year!

Destination Jet (600 mph) Rocket (25,000 mph) Sunbeam (186,000 miles/second)

Moon 16.5 day 9.4 hours 1.2 secondsSun 17 years, 8 months 4 months 8.5 minutesMercury 10 years, 10 months 3 months 5 minutesVenus 5 years, 5 months 1.5 months 2.5 minutesMars 8 years, 10 months 2.5 months 4 minutesJupiter 74 years, 3 months 1 year, 9 months 35 minutesSaturn 150 years, 5 months 3 years, 7 months 1 hour, 11 minutesUranus 318 years, 6 months 7 years, 7 months 2 hours, 30 minutesNeptune 513 years, 2 months 12 years, 3 months 4 hours, 2 minutesPluto 690 years, 1 month 16 years, 5 months 5 hours, 25 minutesAlpha Centauri (nearest star)

4.8 million years 114, 155.2 years 4.2 years

Sirius (Dog star) 9.6 million years 228,310.4 years 8.4 years

Pleiades Cluster (7 Sisters)

400 years

Catherine (AKA Crab) Nebula

4,000 years

Center of the Milky Way

38,000 years

Andromeda Galaxy 2.2 million years

* Average distance from Earth: 93 million miles (150 million kilometers)

* Radius: 418,000 miles (696,000 kilometers)

* Mass: 1.99 x 1030 kilograms (330,000 Earth masses)

* Makeup (by mass): 74% hydrogen, 25% helium, 1% other elements

• Average temperature: 5,800° Kelvin (surface),

15,500,000 ° Kelvin (core)

* Average density: 1.41 grams per cm3

* Volume: 1.4 x 1027 cubic meters

* Rotational period: 25 days (center) to 35 days (poles)

* Distance from center of Milky Way: 25,000 light years

* Orbital speed/period: 138 miles per second/200 million years

Solar Facts

Nuclear FusionHydrogen to Deuterium

Deuterium to Helium-3

Helium-3 to Helium

Galaxies Massive, gravitationally bound systems that consists of stars and

stellar remnants, an interstellar medium of gas and dust, and an important but poorly-understood

component tentatively dubbed dark matter.

Galaxies are grouped into larger units known as

clusters. Our own Milky Way Galaxy belongs to the Local Group, and contains

about 45 galaxies of various size and shape.

Galaxy Types

Types of galaxies according to the Hubble classification scheme.

E = EllipticalS = SpiralSB = Barred Spiral, a type of irregular galaxy

Elliptical Galaxies

Shaped like large, 3-dimensional ellipses.

Shapes range from nearly spherical to highly

flattened; Size ranges from hundreds of millions to over one trillion stars.

Galaxy M49a

Galaxy Messier 59

Spiral Galaxies Consist of a flat, rotating disk of stars, gas and dust,

and a central concentration of stars known as the bulge. These are surrounded by a much fainter halo of stars, many of which reside in globular clusters.

Andromeda Galaxy

Sombrero Galaxy

Pinwheel Galaxy

Irregular Galaxies

This category contains all the galaxies that do not fit into the spiral or elliptical class. It includes such types as barred spiral, lenticular, dwarf, and ring galaxies.

Hoag’s Object, a Ring Galaxy

Magellanic Cloud, an irregular dwarf galaxy

NGC 1300, a Barred Spiral Galaxy

When Galaxies CollideCollisions occur when two galaxies pass

directly through each other and have sufficient relative momentum not to

merge. Stars within the galaxies may not actually hit one another, but the gas and

dust in each galaxy will mix and can trigger a burst of star formation.

The Milky Way GalaxyThe Milky Way, sometimes called simply the Galaxy, is the

galaxy in which our Solar System is located. It is a barred spiral galaxy that is part of the Local Group of galaxies. It is one of

billions of galaxies in the observable universe.

The Milky Way as seen from Death Valley, 2007. This is a panoramic picture.