solar physics advanced space academy u.s. space & rocket center

SOLAR PHYSICS

Advanced Space Academy

U.S. Space & Rocket Center

SOLAR PHYSICS

Why the Sun?The Ozone HoleSolar StructureSolar FeaturesSolar Missions

Why The Sun?

Clues to our origins

Curiosity

Energy Source

Predict communication

problems

Avoid endangering astronauts and spacecraft

http://science.nasa.gov/headlines/y2001/ast17sep_1.htm

The Ozone Hole

16,000,000 square miles (26,000,000 square km) in size

Mainly located over Antarctica; however, its boundaries can extend upward uncovering portions of Australia, South America, and South Africa

Exacerbated by CFC’s

Solar Structure

Early Life– Gas & dust

– Shock waves & gravity

– Contraction increased pressure and temperature

– Fusion at 15 million degrees F (8.3 million degrees C)

– Electromagnetic radiation

http://www.windows.ucar.edu/tour/link=/sun/statistics.html&edu=high

Sun Facts

Mass - 1 billion trillion trillion tons330,000 times the Earth’s massDiameter - 864,000 miles (1,390,000 km)75% Hydrogen and 25% Helium by mass93,000,000 miles (150,000,000 km) from

EarthThe sun is an average G2 star

(classification on next slide)

Sun Facts: Classification G2

http://windows.arc.nasa.gov/tour/link=/sun/sun.html&edu=high

Solar Structure

4 layers:– Core

– Photosphere

– Chromosphere

– Corona

Radiation Travel Times:– millions of years from core

to chromosphere

– 8 minutes to Earth

Striated rotation

MidlifeOur Sun contains 99.9% of the

matter in our solar system

http://windows.arc.nasa.gov/tour/link=/sun/activity/solar_cycle.html&edu=high

The Solar Cycle

The Sun goes through a cycle every 11 years

Solar MinimumSolar MaximumThe 11 year sunspot cycle is actually

related to a 22 year cycle for the reversal of the Sun's magnetic field.

Our Sun is an Active Star

http://science.msfc.nasa.gov/ssl/pad/solar/interior.htm

Solar Midlife - Core

Temperature – 27,000,000°F (15,000,000 °C)

Pressure - 250 billion atmospheres

The Radiative ZoneThe Interface LayerThe Convection Zone

Solar Midlife - Core

MAGNETISM – the key to understanding the Sun

The magnetic field is produced in the Sun by the flow of electrically charged ions and electrons most likely in the interface layer

http://science.msfc.nasa.gov/ssl/pad/solar/surface.htm

Solar Midlife - Photosphere

Temperature - 10,500°F (5,800ºC)

The sun’s lower atmosphere

62 miles (100 km) thick It gives off most of its

energy as visible light and heat

Sunspots originate on this layer

http://www.space.com/scienceastronomy/top10_2002_021224-8.html

Photospheric Features

SUNSPOTS appear as dark spots on

the sun They are really several

spots clustered together They originate at the poles They are magnetic Sunspots are “cool”

regions - 6,800°F (3,800ºC) compared to their surroundings


SUNSPOTS– Observing sunspots

“moving” across the Sun was how scientists figured out that the Sun actually rotated

http://science.msfc.nasa.gov/ssl/pad/solar/feature1.htm


FACULAE– Bright areas seen near

the edge of the solar disk

– These are magnetic areas but the magnetic field is in smaller bundles than in sunspots



GRANULES– Small cellular features that

cover the entire Sun except for those areas covered by sunspots

– Individual granules last for only about 20 minutes

– The flow within the granules can reach supersonic speeds and produce sonic “booms” that generate waves on the Sun’s surface



SUPERGRANULES

– Much larger versions of granules

– The fluid flows observed in supergranules carry magnetic field bundles to the edges of the cells where they produce the chromospheric network

Solar Midlife - Chromosphere

Faint and red - seen only briefly during an eclipse

Temperature rises from 10,800°F (6,000ºC) to 36,000°F (20,000ºC)

http://science.msfc.nasa.gov/ssl/pad/solar/feature2.htm#Network

Chromospheric Features

CHROMOSPHERIC NETWORK

– Web-like pattern

– Outlines the supergranule cells seen on the photosphere



FILAMENTS – dense, somewhat

cooler, clouds of material suspended above the chromosphere by loops of magnetic field

PLAGE – bright patches above

sunspots



PROMINENCES– dense clouds of material

suspended above the surface of the Sun by loops of magnetic field



SPICULES– Small jet-like

eruptions seen throughout the chromospheric network


SOLAR FLARES – can release as much energy as a billion megatons of TNT

http://science.msfc.nasa.gov/ssl/pad/solar/t_region.htm

Transition Region

A very thin, irregular layer of the Sun that separates the chromosphere from the corona

Temperature changes very rapidly in this region and causes hydrogen to become stripped of its electrons.

The light emitted by the transition region is dominated by ions illustrated in the pictures

http://science.msfc.nasa.gov/ssl/pad/solar/corona.htm

Solar Midlife - Corona

The Sun’s outermost atmosphere

Temperature is 1,800,000°F (1,000,000°C)

The Solar Corona – The White-Light Corona

– The Emission Line Corona

– The X-Ray Corona



EMISSION LINE CORONA

Since hydrogen atoms have been ionized only the heavier trace elements like iron and calcium are able to retain a few of their electrons in this intense heat

It is emission from these elements that produce the color associated with the emission line corona



X-RAY CORONA The corona shines

brightly in x-rays because of its high temperature while other layers of the Sun do not emit x-rays

This allows us to view the corona across the disk of the Sun when we use an X-Ray telescope


Coronal Features

HELMET STREAMERS

Large cap-like coronal structures with long pointed peaks that usually overlie sunspots and active regions formed by a network of magnetic loops


Coronal Features

POLAR PLUMESLong thin streamers

that project outward from the Sun’s north and south poles

They are associated with the “open” magnetic field lines at the Sun’s poles


Coronal Features

CORONAL LOOPS Found around sunspots

and in active regions Associated with the

closed magnetic field lines that connect magnetic regions on the solar surface

Some loops appear after solar flares


Coronal Features

CORONAL HOLES Regions where the corona

is dark Associated with “open”

magnetic field lines and are often found at the poles

The solar wind originates in coronal holes

http://www.gsfc.nasa.gov/topstory/20021030solar.html

Coronal Features

CORONAL MASS EJECTIONS (CMEs)

huge bubbles of gas threaded with magnetic field lines that are ejected from the Sun over the course of several hours.

CMEs can disrupt the flow of the solar wind

CMEs are often associated with solar flares and prominence eruptions but they can also occur in the absence of either of these processes.

http://antwrp.gsfc.nasa.gov/apod/ap020101.html

The Solar Wind

The solar wind streams off of the Sun in all directions at speeds of about 1 million miles per hour

The source of the solar wind is the Sun's hot Corona

The temperature of the corona is so high that the Sun's gravity cannot hold on to it

http://sohowww.nascom.nasa.gov/

The Solar and Heliospheric Observatory (SOHO)

The SOHO spacecraft is a joint effort between NASA and ESA

It was launched on December 2, 1995

SOHO will take measurements of the solar interior, the solar atmosphere, and the solar wind

http://antwrp.gsfc.nasa.gov/apod/ap021221.html

SOHO Images

Composite picture of 3 images taken by the EIT instrument on board SOHO

Each individual image shows a different temperature in the upper solar atmosphere and was assigned a specific color

Red at 2 million degrees F Green at 1.5 million degrees F

Blue at 1 million degrees F

http://vestige.lmsal.com/TRACE/

Transition Region and Coronal Explorer (TRACE)

TRACE will explore the magnetic field in the solar atmosphere

TRACE will work in conjunction with SOHO for part of its mission

It was launched by a Pegasus rocket in April 1998

http://vestige.lmsal.com/TRACE/Science/ScientificResults/trace_cdrom/html/trace_images.html

TRACE Images

Solar flare observed on May 19,1998

A solar flare is a rapid release of energy from a localized region on the Sun in the form of electromagnetic radiation, energetic particles, and mass motions

http://genesismission.jpl.nasa.gov/

GENESIS – Search for Origins

What is the Sun made of? Launched August 8, 2001 Genesis will collect solar

wind samples for 2 years Libration points 22.3 ft (6.8m) solar panel

length 1402 lbs (636 kg) at

launch

http://www.astronomynotes.com/evolutn/chindex.htm

Solar Structure

•The End•Hydrogen depletion

•Red giant

•Fusion stops, outward pressure decreases

•Collapse

•Planetary Nebula

•White Dwarf

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