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57 Cards in this Set
- Front
- Back
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Apparent Magnitude
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How bright the star appears from Earth
Lower # = brighter star most faint we can detect today (with telescopes): 30 most bright we can detect today: -30 |
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Absolute Magnitude
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The apparent magnitude of a
(True Brightness) Lower # = brighter star -Need to know 2 things: how bright star appears DISTANCE (Stellar parallax) |
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Stellar parallax & parsec
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Earth on the East & west sides of the sun (JAN & JULY)
First method used to measure distance to the stars Parsec (Parallax second) = 3.24 ly |
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Light Year (LY)
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The distance that light travels in a vacuum in one year
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Spectral class
O B A F G K M (Oh Be A Fine Guy, Kiss Me!) 25,000k to 3,000K (temp) Very bright to Faint |
O Blue stars
B Blue-white stars A White stars F Yellow-white stars G Yellow stars (like the Sun) K Yellow-orange stars M Red stars |
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Luminosity class (surface area/size)
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The luminosity class broadly indicates whether a star is a dwarf (that is, a main sequence star), a giant, or a supergiant, since luminosity is directly related to surface area. Luminosity class is expressed as a Roman numeral, from I to V
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H-R diagram
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Graph in which the absolute magnitudes of stars are plotted against their colours (a measure of their temperatures).
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Binary star
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a star system consisting of two stars orbiting around their common center of mass.
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Cepheid variable
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a member of a class of pulsating variable stars. The relationship between a Cepheid variable's luminosity and pulsation period is quite precise, securing Cepheids as viable standard candles and the foundation of the Extragalactic Distance Scale.
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Planetary nebula
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A ring-shaped nebula formed by an expanding shell of gas around an aging star
Stellar phase after the red super giant star phase, in which we see the rapid expansion of the external star layers and the remaining hot core (white dwarf). |
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white dwarf
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A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. Near the end of its nuclear burning stage, this type of star expels most of its outer material, creating a planetary nebula. Only the hot core of the star remains.
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Black dwarf
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A cold celestial object thought to be the remains of a dead star of low mass that is formed after a white dwarf star has radiated away most of its heat energy.
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Nova
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A star that suddenly becomes much brighter and then gradually returns to its original brightness over a period of weeks to years.
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Chandrasekhar limit
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The maximum size of a stable white dwarf,
approximately (about 1.4 times the mass of the Sun). Stars with mass higher than the Chandrasekhar limit ultimately collapse under their own weight and become neutron stars or black holes. Stars with a mass below this limit are prevented from collapsing by the degeneracy pressure of their electrons. |
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white dwarf supernova
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A carbon-oxygen white dwarf that approaches this mass limit, typically by mass transfer from a companion star, may explode as a Type Ia supernova via a process known as carbon detonation.
Supernovae are the primary suppliers of heavy elements for the universe. Elements necessary for life, such as carbon and oxygen, as well as heavier elements like iron, are produced by nucleosynthesis within the star. In the explosive death of the star, these elements are thrown out so that they may be recycled by other stars and gases. |
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Massive star supernova
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The ultimate fate of a star depends on its initial mass.
A massive star ends with a violent explosion called a supernova. |
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neutron star
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one of the possible final outcomes of stellar evolution, in which a massive star goes through a supernova and all remaining particles within the star collapse into their least energetic states
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Pulsar
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A rotating neutron star which generates regular pulses of radiation.
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Black hole
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If remaining mass is more than 3 solar masses the star will collapse into a black whole
- the black whole becomes infinitely small - Gravity of the star is HUGE! - Space is warped - Light cannot escape |
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Singularity
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Infinite center of black whole
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Event horizon
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The region, usually described as spherical, marking the outer boundary of a black hole, inside which the gravitational force is strong enough to prevent matter or radiation from escaping.
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Milky way Galaxy
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The sun is located in a spiral arm
-28,000 Ly from the center -2/3rds of the way out -Center of the Galaxy is in Sagittarius (A) part of the sky Center of galaxy in visible light looks dark because of dust Inferred Image you can see through the dust -A super massive black whole "lives"at the center of the Milky way - Millions of times more massive than a single star |
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Super massive black whole
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the largest type of black hole in a galaxy, on the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way,[2] are believed to contain supermassive black holes at their centers.[3][4]
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Local Group
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cluster that the milky way lives in (30 in total)
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Cosmological redshift
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An effect where light emitted from a distant source appears redshifted because of the expansion of spacetime itself. Compare Doppler effect.
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Hubble Law
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Measures redshift of Galaxies
(correlation to distance and velocity) "the faster the Gal, the farther away it is" |
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Big Bang
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NOT and explosion in space
- Creation of space and time - There was no space and no time before big bang - Immediately following creation of space and time, space began expanding - The BIG BANG is still going on, and we are inside of it |
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Cosmic microwave Radiation
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Cosmic background radiation is well explained as radiation left over from an early stage in the development of the universe, and its discovery is considered a landmark test of the Big Bang model of the universe.
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Cosmology (Space expansion)
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-Study of the origin and evolution of the universe
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Spectral Classes
O B A F G K M |
OB'S: big hot blue stars
KM's: cool red stars Hottest: Brightest: Most massive: live the longest: live the shortest: |
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Star temp measurement
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Spectral Classification System
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Star composition measurement
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Measuring Distance of stars
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Measuring Size of stars
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Calculate Mass – any binary star system
Calculate Size – eclipsing binary |
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Relationship between Absolute mag., Apparent mag., & distance
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you need any two of these to measure the third
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Types of Galaxies
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Spiral
elliptical irregular |
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Hubble & Hubble law
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Hubble proved existence of galaxies.
Hubble law: Implications of Hubble law: |
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Big bang theory & evidence
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Cosmological redshift cosmic background radiation cosmic abundance of elements |
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Seasons
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moon phases
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eclipses
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circumpolar and seasonal const.
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Significance of zodiac
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Significance of North Star
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How to tell a planet from a star
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How many planets can you see without a telescope
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5 planets visible without a telescope, Mercury, Venus, Mars, Jupiter, and Saturn
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Angular measurement
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Astronomers measure angular separation of objects in degrees from their point of observation.
1° is approximately the width of a little finger at arm's length. 10° is approximately the width of a closed fist at arm's length. 20° is approximately the width of a handspan at arm's length. |
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Aurora borealis
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History of Astronomy
key ideas and people |
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Telescopes and light
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Doppler effect
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for electromagnetic waves such as light is of great use in astronomy and results in either a so-called red shift or blue shift. It has been used to measure the speed at which stars and galaxies are approaching or receding from us
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Electromagnetic spectrum
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Solar system
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comets:
meteors: – a streak of light in the sky caused by a particle entering the atmosphere asteroids: Pluto: Sun: |
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Major features of planets
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Order of planets from sun
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Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
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Difference between a meteor, meteorite, meteoroid, meteor shower.
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Meteor: "shooting star" a streak of light in the sky caused by a particle entering the atmosphere
Meteorite: meteoroid: meteor shower: dust from comet tail entering atmosphere |
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The sun and what powers it
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Nuclear fission
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