Term
| What is the diameter of the Sun? |
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Definition
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Term
| What is the Sun mostly composed of? |
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Definition
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Term
| What is the temperature of the sun on the surface? What about the center? |
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Definition
6000k (surface)
15.6 million K (center) |
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Term
| What does Luminosity mean? |
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Definition
| Total energy emitted/sec by a star |
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Term
| What are the layers of the Sun? |
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Definition
1.Photosphere (Outer most), which is the section of the sun that you see.
2.Chromosphere
3.Corona (Center) |
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Term
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Definition
| Jet of hot (gas) plasma made up of protons and electrons |
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Term
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Definition
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Term
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Definition
| Sudden burst of light energy |
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Term
| What is the composition of solar wind? |
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Definition
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Term
| Sunspots and the differential rotation at the equator and the poles |
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Definition
Equator ~ 25 days (fastest)
Either pole ~ 35 days (slowest) |
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Term
| The Sunspot Cycle is on a ____ year cycle. |
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Definition
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Term
| What is the Babcock or Dynamo Theory? |
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Definition
1. Sun rotates differentially
2. Magnetic field sticks to the surface
3. Rotation winds up field, causes knots or kinks to form sunspots
4. Production of Large numbers of spots smooth’s out field again |
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Term
| Is the sun a Variable Star? |
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Definition
| --No, not in the sense that optical astronomers use the term. Some stars get 50% brighter or dimmer with time! |
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Term
| Is the Sun very consistent? |
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Definition
--Yes--
The Sun’s light and heat output remains remarkably constant over time. |
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Term
| What is the name of the time period when their were no visible sunspots? |
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Definition
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Term
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Definition
--A heavy nucleus “splits” and releases energy
-- Not the source of the Sun's energy -- |
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Term
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Definition
Low mass nuclei "join" and release energy
-- Source of Sun's energy -- |
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Term
| When two protons fuse together is their mass more or less than before fusion. |
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Definition
Less
(the mass is being converted into energy) |
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Term
| What does E=mc2 stand for |
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Definition
| Energy=(mass)X(speed of light)2 |
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Term
| What do the 2 hydrogen molecules fuse into, and what is this called? |
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Definition
--1 Helium,
--Thermonuclear Fusion of Hydrogen into Helium |
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Term
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Definition
| Proton (nucleus of hydrogen atom) |
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Term
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Definition
| Deuteron (nucleus of deuterium) |
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Term
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Definition
| Neutrino (“no change, no mass; always travels at the speed of light”) |
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Term
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Definition
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Term
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Definition
| = positron (antimatter twin of e-) |
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Term
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Definition
| gamma ray (packet of energy) |
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Term
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Definition
| nucleus of “light” helium |
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Term
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Definition
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Term
| Interior of the Sun (Theory). |
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Definition
1.The material in the Sun should behave like a gas on Earth does.
2.The sun is neither expanding nor contracting.
3.The Sun is not cooling off.
4.There must be an internal energy source for the sun |
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Term
| What is the Average Density of the Sun, what about the center? |
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Definition
1.4 gm./cm3
150 g/cm3 (center) |
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Term
| The material in the Sun should behave like a gas on Earth is called what? |
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Definition
Pressure-temperature relation:
ideal gas law |
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Term
| What is it called when the sun is neither expanding nor contracting? |
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Definition
Hydrostatic equilibrium:
a pressure-depth law |
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Term
| Why is the Sun not cooling off? |
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Definition
Thermal Equilibrium:
rate at which energy leaves the surface equals the rate at which it reaches the surface from interior. Energy is transferred by radiation or by convection. |
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Term
| What is the internal energy source for the sun |
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Definition
| Thermonuclear fusion of hydrogen into helium |
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Term
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Definition
| Sound waves traveling through interior show up as surface pulsations |
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Term
| Who built a solar neutrino detector from a tank of 100,000 gal. Of dry-cleaning fluid in an old mine 1 mile underground, and why? |
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Definition
Raymond Davis
More of a controlled experiment with less interactions. |
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Term
| How many different kinds of neutrinos are there, and can they morph from one to another? |
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Definition
There are 3 different types and
yes they can morph from one another. |
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Term
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Definition
| Fusion at room temperature |
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Term
| How many Nuclear Fission/Fusion Reactors does the US have and what percentage of the worlds Nuclear reactors is that? |
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Definition
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Term
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Definition
| It is the APPARENT magnitude/brightness a star has at it’s current distance. |
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Term
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Definition
| ABSOLUTE Magnitude/ Brightness a star would have if seen from a standard distance of 10pc (parsec) = 32.6 LY |
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Term
| Why is there a standard distance of 10pc (parsec) or 32.6 LY? |
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Definition
| To relate all stars to a controlled distance to study the absolute magnitude of a star. |
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Term
| What is the Distance Modulus, and what is it a measure of? |
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Definition
Apparent magnitude (minus) Absolute magnitude of a star,
=the distance of a star from Earth. |
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Term
| What is the Distance Modulus equation? |
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Definition
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Term
| The color of a star depends on its surface temp. The redder the star appears, the ______ its surface. |
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Definition
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Term
| What color filter is most commonly used? |
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Definition
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Term
| When are the lines produced by hydrogen the darkest? |
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Definition
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Term
| What is the purpose of spectral classification? |
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Definition
| To determine the surface temperatures of stars. |
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Term
| Why were classes L and T added? |
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Definition
| Brown Dwarfs (failed stars) are so cool that they added the extra classes. |
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Term
| What does the spectrum of a star contain information about? |
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Definition
Its surface temperature.
Each element produces a unique pattern of spectral lines. |
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Term
| What is Proper motion and what is this due to? |
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Definition
Is the apparent “sideways” change in position of a star on the sky, measured in arc sec/year.
This is due to the actual “sideways” velocity of a star. |
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Term
| What is the star with the greatest proper motion is called? |
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Definition
| Barnard's star. It moves ~10”/year.( |
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Term
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Definition
| VR= the speed of a star toward or away from the solar system along the line sight. |
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Term
| What is Transverse Velocity, and how is it measured? |
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Definition
| VT= The speed of a star perpendicular to the line of sight This is measured using the star’s proper motion and knowledge of its distance. |
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Term
| What is Space Velocity, and how is it calculated? |
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Definition
| VS = the actual speed and direction of a star in 3-d space. The Pythagorean Theorem |
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Term
| What is the closest star to our solar system? |
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Definition
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Term
| Are most nearby stars more or less luminous than the sun? |
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Definition
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Term
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Definition
apparent visual magnitude = V |
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Term
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Definition
| apparent red magnitude = R, etc. |
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Term
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Definition
absolute visual magnitude |
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Term
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Definition
| absolute red magnitude, etc. |
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Term
| What are the temperatures of the layers of the Sun? |
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Definition
6000k = Photosphere
4500-100,000k =Chromosphere
100,000-millions = Corona |
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Term
| What are the most common stars that are our neighbors like? |
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Definition
| Cool, red, low-luminosity stars like Barnard’s star. |
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Term
| Antares is about 10,000 times more luminous than the sun, What is its luminosity? |
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Definition
10 magnitudes more luminous
M = -5 |
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Term
| A star with luminosity of 1/100 that of the Sun would have _____ M. |
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Definition
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Term
| What is a “Optical Double”? |
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Definition
| Two stars aligned by chance. This is not a binary system. |
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Term
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Definition
Visual:
2 or more stars orbiting a common gravitational center, visible as two stars in a telescope.
Astrometric:
Presence of second star shown by wavy proper motion.
Spectroscopic:
Presence of 2 stars shown by doubled and/or moving spectral lines.
Eclipsing:
2 stars get in each other’s way because the plane of their orbit is in our line of sight |
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Term
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Definition
| two stars aligned by chance. This is not a binary system. |
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Term
| What does Visual stand for in reference to Binary stars? |
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Definition
| 2 or more stars orbiting a common gravitational center, visible as two stars in a telescope. |
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Term
| What does Astrometric stand for in reference to Binary stars? |
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Definition
| Presence of second star shown by wavy proper motion. |
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Term
| Why do we care about visual binaries? |
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Definition
| So we can measure the mass of stars. |
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Term
| Is the Mass-Luminosity Relation very consistently related? |
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Definition
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Term
| What does Spectroscopic stand for in reference to Binary stars? |
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Definition
| Presence of 2 stars shown by doubled and/or moving spectral lines. |
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Term
| What does Eclipsing stand for in reference to Binary stars? |
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Definition
| 2 stars get in each others way because the plane of their orbit is in our line of sight |
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Term
| Do the stars in a binary system orbit a common center of gravity? |
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Definition
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Term
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Definition
| displays a graph with the relationship between the luminosity and surface temperatures of stars. |
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Term
| Most stars in any large group occupy a region known as the _______ and represent normal stars. |
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Definition
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Term
| Is it easier to determine absolute magnitude or luminosity? |
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Definition
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Term
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Definition
| The apparent shift in position of an object as we change our viewpoint. |
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Term
| What is Stellar Parallax? |
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Definition
| The apparent shift in position of a star as we change our viewpoint while the Earth orbits the Sun: |
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Term
Example:
Alpha Centauri has p = 0.77 “
Find the distance in light years |
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Definition
| d = 1/.77 = 1.34 pc then (multiply) by 3.26 and get 4.36 L.Y. |
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Term
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Definition
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Term
| What are The Three Categories of Variable Star, and define each category? |
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Definition
Eclipsing
What looks like a single star changing brightness is actually two getting in each other’s way.
Eruptive
Some of these get brighter by ejecting hot material, others dimmer by ejecting particles, which shade their light.
Pulsating
These single stars expand and contract rhythmically due to structural instability |
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Term
| Cepheid variables range on a ____ to _____ day period. |
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Definition
1 < P < 100 day
a.k.a. 1-100 day period |
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Term
| What did Henrietta Leavitt discovered early in the 1900s about the star Cepheid? |
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Definition
| that the longer the period of a Cepheid, the brighter the star is. |
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