Astronomy The Sun, Our Star

What is the chromosphere?

"Sphere of color" visible during solar eclipses

How are the other classifications below O subtyped?

0-9

What 2 things can change luminosity of a star?

1. Change in size 2. Change in temp.

What 3 things can cause the brightness of a star to vary?

1. Change in size. 2. Change in temp. 3. Change in distance.

What two specific things must you know for the HR Diagram?

1. Luminosity vs temp (most common and most important) 2. Absolute magnitude vs spectral type 3. And least common would be apparent magnitude vs color index.

What are things you can tell based on the line about nature?

1. Nature prefers to make lower mass stars, it doesn't like to make huge mass stars very often. 2. You can tell if a star is on the main sequence you can tell what it's total life time will be from birth to death. (The sun is halfway through its life)

What are the stellar luminosity classes?

1. Supergiants 2. Bright giants 3. Giants 4. Subgiants 5. Main-sequence stars/dwarfs.

For the sun's interior what are the three ways that the sun moves energy out of its core?

1. Thermonuclear core 2. Radiative zone 3. Convective zone

What does 1 arc second =

1/3600 degrees

How long is the sun spot cycle?

22 years total.

What does 1 parsec =

3.26 light years.

What does a degree =

60 arc minutes. 60 arc minutes = 1 arc minutes. 1 arc minute = 60 arc seconds.

What elements is the sun comprised of?

91.2% Hydrogen, 8.7% Helium, .1% other. Every star is mostly hydrogen.

What is a parsec?

A distance of measurement. It is the distance from our sun at which the angle between the Earth and the sun subtends an angle of one arc second.

What is the convection zone?

A layer inside a star where energy is transported outward by means of heat flow through the gases of the star (convection.)

What happens when an electron return to a lower energy level?

A photon is emitted.

What is the radiative zone?

A region inside the star where energy is transported outward by the movement of photons. They bop around until they reach the surface of the star.

What is an neutrino?

A subatomic particle with a very very small amount of mass and can ALMOST travel the speed of light.

How do you get an electron excited?

Add heat or shine light.

What is a positron?

An electron with a positive charge.

Does the apparent brightness of a star increase or decrease with distance from the Earth?

Apparent brightness decreases with increasing distance from the Earth.

What is the formula for stellar brightness?

B(brightness)=L/4pisymbolxd(distance)^2

Why do certain spectral lines look different?

Because every atom's electrons have unique energy levels (orbitals in the electrons). Spectra (spectrum) of are star are "fingerprints" of each element.

Why are sunspots cooler?

Because magnetic fields carry away energy.

Do bigger or smaller stars have more energy?

Bigger stars.

How do we measure size (radius)?

Brightness and luminosity. Stephan-boltzman law.

Do closer or further objects exhibit more parallax?

Closer objects.

How do we measure temp?

Color. Accurately is the spectral types. Letter and number.

What are granuales?

Convection features about 1000 kilometers in diameter seen constantly in the solar photosphere.

What is Kirchoff's third law?

Cool gas in front of a continuous source of light produces an absorption line spectrum. Example: the sun. Rainbow with dark lines.

What does luminosity deal with?

Distance and radius. This is questionable. Don't believe this one.

What is a light year?

Distance that light travels in one year.

How do we measure speed of light coming from a star?

Doppler effect for whether its moving away or towards us. Doesn't work if its moving straight across the sky.

What was able to explain what looked like mass loss in an energy reaction?

E=mc^2, which means that the extra mass was converted to pure energy. And vice versa.

What are more examples of variable stars?

Eclipsing binary stars, cepheid variables, and mira varibales.

Can energy be created or destroyed?

Energy can neither be created nor destroyed and you can only change it from one from/type to another.

How is the sun spot cycle broken up into years?

Every 11 years on average you go up and down in the # of sun spots, then after that the magnet flips and another 11 years goes by before the magnet flips again and then the cycle. ends.

What is fission?

Fission is taking one large atom and breaking it apart and it releases energy.

What is prominence?

Flamelike protrusion seen near the limb of the sun and extending into the solar corona.

What kind of stars do you measure apparent and absolute magnitude with?

Further stars, or when parallax won't work.

Why does small mass lives longer than bigger?

Fusion is happening faster in bigger stars and they burn through large amounts of fuel faster.

What is fusion?

Fusion is taking two small molecules and smashing them together and that creates energy.

Where is the sun on the scale?

G2

What is the force that keeps stars together inward?

Gravity. But if it were just gravity than the gravity would crush all the material together.

What is Kirchoff's second law?

Hot, rarefied (low density) gas produces an emission line spectrum. Example: a neon sign

What is apparent magnitude?

How bright does any object look to the naked eye.

What is stellar luminosity?

How much energy given off. The amount of energy a star radiates.

What does the differential rotation do?

It causes the number of sunspots to vary over an 11 year period. (The rubber band twist)

What is helioseismology?

It is the way we can see into the sun's inner core, like a seismic motion going through the sun.

What do we use to measure the temp of the star and why?

Kelvin, it uses a physical 0 because there is no cooler in the universe than you can get from it.

What is actually happening when you get an electron excited?

Light is a wave or a photon and if you hit the electron with the photon version it's a particle hitting another particle. It gives it some energy and allows it to move. Electrons don't like energy, so the electron will naturally want to give it off.

How do you measure absolute magnitude?

Line up all the stars you're looking at at the same distance of 10 parsecs and then how bright they are to your eyes.

What is the formula for luminosity?

Lsun=3.8 x 10^26 watts

What is the magnitude system?

Measurement of how bright the stars are.

What causes the magnetic field on the sun and what does it do?

Motions inside the sun and for it to move and create a sun spot.

What kind of stars do you measure parallax with?

Nearby stars.

What is a problem with looking at neutrinos?

Neutrinos react very little with ordinary matter so detecting them is difficult. They go right through nearly everything without a problem.

Can you rid of an electrical charge?

No you can't.

Can you observe luminosity?

No, it can only be calculated.

Would you see granules on a big star?

No, the convection zone on huge stars is on the middle layer so you would not see it on the surface.

Do electrons actually jumps between ionization levels?

No, they can literally only be in one or the other, never in between.

Can you find the size of a star anywhere but the diagram?

No.

For two stars of the same brightness, the closer star to the sun will generally have:

Not apparent magnitude. The closer star will have lower luminosity.

What are the subtypes for the classification of O?

O 3-9 with 03 being the hottest a star could ever be.

What is the order of the hot scale of stars?

O B A F G K M L T Y

Who was annie cannon?

One of the first true women astronomer's and a professor at Harvard.

What is the corona?

Outermost layer of the sun's atmosphere.

How do you find the distance of the star when its reasonably close to earth?

Parallax, and then apparent and absolute magnitude if it's further. Parallax is more accurate.

What is the Hertzsprung Russell Diagram?

Plots of data for known stars.

What is a famous example of a variable star?

Polaris.

What is the force that keeps the sun from collapsing on itself (outward?)

Pressure force

What type of chain do smaller stars use to make their energy?

Proton-proton chain, the 4 hydrogens into 1 helium.

What do the colors red, blue and yellow tell you about star temp and energy?

Red= cold, least energy Blue= hot, most energy Yellow= in between

Is a bigger or smaller number for the logarithmic scale of apparent magnitude brighter?

Smaller numbers are brighter. - numbers are much brighter.

What is the order of really big stars to moving energy out of its core?

Some big stars start with the thermonuclear core, then the convection and then radiation.

What is the inverse square law?

Some quantity divided by something squared.

Do all small stars have a radiative zone?

Some small stars don't even have a radiative zone, sometimes just a thermonuclear core and a convection zone.

Why do stars use fusion and not fission, when they could use either?

Stars are mostly made of hydrogen which is a small atom, so it uses fusion which deals with two small atoms smashing together. Stars know how to control fusion.

Do stars use fusion or fission?

Stars only use fusion, NEVER fission.

What are white dwarfs? What are super giants and giants doing?

Stars that are already dead. Giants and supergiants are dying.

What is a variable star?

Stars that have a noticeable change in brightness over time.

What is something wrong apparent magnitude?

Subjective to who is looking and their eyes.

What is the solar cycle traced by?

Sunspots, latitude and rate of solar flares.

What is the photosphere?

Surface of any star, gaseous surface, visable. "Sphere of light" the visible surface of the sun.

What is the stefan-boltzmann law?

THe formula is L(luminosity)=4pisymbolR^2sigmaT^4. R=radius, size of the star and T=temperature of the star.

What do spectra brightness' tell you and not tell you?

Tells you the energy but not what the chemical is.

What is a sunspot?

Temporary cool region in the solar photosphere created by protruding magnetic fields.

What did the standard solar model predict about neutrinos?

That billions of netrinos persecond flow from the sun.

What is Kirchoff's first law?

That dense gas or solids produce a "continuous spectrum" a rainbow. Example: light bulb filament.

What is the differential rotation?

That is the motion of the equator spinning and it twists the magnetic field lines.

What is the Maunder minimum?

The 70 year period between 1645 and 1715 there were virtually no sun spots.

Is the CNO part of the cycle ever actually used up or consumed?

The CNO part of the cycle is never consumed but is a catalyst to get the reaction to start.

What is absolute magnitude?

The apparent magnitude that a star would have if it were 10 parsecs away from the Earth.

What is the standard solar model?

The generally accepted theory of solar energy production. A model on a computer spits out how the sun should work when we look at the sun. It predicts exactly what we're seeing.

What is parallax?

The illusion of why things have retrograde, apparent change.

What are spectral types?

The letter classifications that tell you how hot a star is according to its appearance.

What is apparent magnitude measured in?

The logarithmic scale of brightness for stars. And the size of the dots on star charts indicates brightness.

How do we measure the brightness, on a scale as well?

The magnitude scale. Also temp, size and distance go into brightness.

What is the output of all the energy star's make?

The main part is 4 hydrogen atoms put together to make 1 helium atom. You also give off 2 positrons, 2 neutrinos and you get energy in every form of light.

If two stars are on the main sequence and one is more luminous than the other what can we be sure of?

The more luminous star is more massive.

What is the solar wind?

The outflow of gas in the corona.

What is hydrostatic equilibrium?

The outward pressure force balances the inward gravitational force everywhere inside the sun. Gravity and pressure keep pushing on each other to keep stars going.

What is in the gas that flows out in the solar wind?

The protons and electrons that have escaped the sun's gravity.

What are the two things that luminosity depends on?

The radius of the star and the temperature of the star.

Why is there a solar cycle? (The up and down, not the flip of the magnet.)

The rotation rate varies from once every 25 days to once ever 30 days. The equator is spinning faster than the poles.

What is the zeeman effect?

The splitting of some of the spectral lines of a hydrogen gas into two or more components.

What is the main sequence line?

The stars line up there because the 80% spend most of their lives changing hydrogen into helium. The other 20% are dead or are dying.

What is stellar spectroscopy?

The study of the properties of stars by measuring absorption line strengths, which shows how obvious or dark a chemical is for it being there.

How many times bigger is the sun than the earth and is the earth a small, average or large star?

The sun is 109 times bigger than the radius of the Earth. The sun is an average sized star compared to others.

What class of star is the sun?

The sun is an G2V star and is classified by how how it is and our star is average.

What is the trend in the latitude of the sunspot cycle?

The sunspots start at 30* N/S and then move up or down S or N towards each other and then it will reach the equator and go up and down.

What is the surface temperature of the sun and its central temp?

The surface temperature of the sun is 5800K and its centeral temperature is 15 million kelvin.

What was the problem with the telescope and the neutrinos we counted?

The telescope indicated that only 1/3 of the neutrinos predicated by the theory model are seen? So where were they and did this mean that our model was wrong?

About how many stars are within 10 parsecs of earth?

There are about 300 stars.

What makes the sun shine?

Thermonuclear fusion at the sun's core is the source of the sun's energy.

What are huge solar flares and how much energy do they release?

They also come from sun spots, but move along the magnetic field still but they are violent enough to break free of the sun's gravity. They release high energy particles released.

Where do solar prominences come from?

They come from sun spots?

What did HR diagram notice about 80% of any sample stars they took?

They could take and plot the stars and 80% would follow along a diagonal curve called the main sequence.

What does each chemical produce from the open flame test.

They found that the elements produced its own characteristic pattern of bright spectral lines.

What happens when a star stars to die?

They get colder and bigger.

What type of chain or cycle do bigger stars use to make their energy?

They use the 6 step cycle which is the CNO cycle.

What is the job of the thermonuclear core?

This is the central region of sun where fusion takes place due to high temperatures and pressure. This is always the first way energy is moved, despite size of star.

What is the job of a star?

To make energy and move it to the surface and then out to space.

What can we use parallax for?

To see if an object is close or not.

Who were Gustav Kirchoff and Robert Bunson?

Two scientists found that burning chemicals over an open flame resulted in a spectrum w/ bright lights.

What are eclipsing binary stars?

Two stars orbit each other, and two different brightness levels are measured when one eclipses another.

What is luminosity measured in?

Watt's, energy per sec.

What was the solution to not being able to detect netrinos?

We built a telescope that could see them. It was the tank with a cleaning fluid inside and when neutrinos went inside they changed into an argon and they could count those.

How can we use the doppler effect to look at a star?

We can see the red and blue shift of gases on the stars surface to see where they are going and how energy is put out.

Do we know why there weren't sunspots during the Maunder minimum?

We do not know, but it did cause a small ice age.

Why did we only see 1/3 of neutrinos that model predicted?

We only thought there was 1 type when there were actually three so the telescope we built only looked for the one type.

How do you find out the exact temp of a star?

We put the star's light through a spectrum and the fan out of color can tell us almost exactly how hot it is.

What do the spectral lines tell you?

What a star is made of.

Is the solar sun spot cycle short term or long term?

What you view from the sunspots is only a cycle looking long term, you can't see patterns short term.

What is absorption?

When a photon causes an electron to jump from a low energy level to a high energy level.

What is emission?

When a photon is emitted after an electron jumps from a high energy level to a low energy level.

Can light be transformed into matter and when does it occur?

Yes and occurs in pair production.

Can you turn mass into light and if so, when does it occur?

Yes this is what occurs during fusion.

Can mass be transformed into light?

Yes, anything can be turned into it because energy is equal to mass.

Can you get an accurate measurement of the mass of the star on the main sequence?

You can't directly, you can get somewhat but not accurately.

Why can't we turn people into light and back?

You wouldn't be able to put each piece back together where you started.

How do we know that sunspots are caused by intense magnetic fields?

Zeeman effect.

What are spectral lines?

dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.