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Physics 101 Final (Astronomy)
Astronomy Final Fall 2013
42
Astronomy
Undergraduate 1
12/07/2013

Additional Astronomy Flashcards

 


 

Cards

Term
Define atom
Definition
The basic unit of a chemical element.
Term
Define nucleus
Definition
A central part about which other parts are grouped or gathered.
Term
Define electron
Definition
subatomic particle with negetivly charged electricity.
Term
Define proton
Definition
Subatomic particle contining a positive electrical charge.
Term
Define neutron
Definition
Subatomic particle with no electricity charge.
Term
Define isotope
Definition
Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei
Term
How do thevarious elements differ from eacho other?
Definition
The atoms in different elements differ from the amount of protons, electrons and neutrons they contain.
Term
Define energy levels.
Definition
The fixed amount of energy that a system described by quantum mechanics, such as a molecule, atom, electron, or nucleus, can have.
Term
Define ground state
Definition
The lowest energy state of an atom or other particle.
Term
Define an excited atom
Definition
Going from a higher energy level to a lower energy level (ground state)
Term
What is meant by blackbody radiation?
Definition
The electromagnetic radiation that would be radiated from an ideal black body; the distribution of energy in the radiated spectrum of a black body depends only on temperature
Term
Features of the Blackbody Spectrum
Definition

1. The higher the temperature of the blackbody emitter, the higher the frequency (or shorter the wavelength) of the predominant light it emits

 

2. Hotter blackbodies give off a lot more energy than cooler blackbodies

Term
Continuous Spectrum
Definition
A spectrum having no lines or bands, especially a spectrum of radiation distributed over an uninterrupted range of wavelengths.
Term
Discrete Spectrum
Definition
Is said to have a discrete spectrum if it takes only distinct values, with positive gaps between one value and the next
Term

Define emission spectrum

 

Definition
A spectrum of the electromagnetic radiation emitted by a source.
Term
Define absorbtion spectrum
Definition

 

A spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption of specific wavelengths.
Term
State Kirchoff's 3 laws and how emisson, absorbtion, and continuous spectrum are made from them.
Definition

1.A hot solid, liquid, or dense gas emits radiation at all wavelengths causing a continuous spectrum.

 

2.A thin hot gas in front of a cooler background emits radiation at a discrete set of isolated wavelengths causing emission lines

 

3.A thin cool gas in front of a hotter solid, liquid, or dense-gas background removes the radiation from the background source at special wave lengths causing absorbtion lines

Term
What are Balmer lines?
Definition
a series of lines in the hydrogen spectrum
Term
Note that hydrogen balmer lines are more pronounced in intermediate temperature stars. Why are they not present in hotter or colder stars?
Definition

1. If the cloud is too hot, the electrons in hydrogen have absorbed so much energy that they can break free from the atom. This is called “ionization,” and ionized hydrogen cannot create absorption lines because it no longer has an electron left to absorb any photons.

 

2. So, if the cloud of gas is too cool, the electrons will all be in the lowest energy level called the ground state and will have weak Balmer lines.

Term
Note that other atoms and colecules, such as calcuim and titanium oxide also profuce absorption bands. Why is titanium oxcide only found in cooler stars?
Definition

 

Other stars are too hot for the molecules of Titanium Oxide to form. Titanium oxide is made of molecules; it is a chemical compound. If the star is too hot, atoms will get bashed into each other too hard for molecules to form.
Term
What is meant by the specteral classes: O, B, A, F, G, A, K, M
Definition

Classifying the stars from a sequence from hottest (O) to coolest (M)

 

The spectral class of a star is a short code summarising the ionizationstate, giving an objective measure of the stars temperature and density.

Term
Stallar Spectrum
Definition
Stars temp by ranging from blue to red. Blue being the hottest and red being the coldest.
Term
Define doppler shift
Definition
The change in the apparent frequency of a wave as observer and source move toward or away from each other
Term
Recognize that when a star is approaching, its spectrum is __________ shifted toward smaller wavelengths, and  that when it is receding its spectrum  is _________ shifted toward longer wavelengths.
Definition

BLUE

 

RED

Term
What are sunspots and how are they formed?
Definition
They form in cycles when the magnetic field bursts through the surface of the sun
Term
Define Parallax
Definition
The effect whereby the position or direction of an object appears to differ when viewed from different positions
Term
When the distance is greater, the parallax is ____________
Definition
Smaller
Term
What does the parallax say about the stars?
Definition
The more the stars move, the closer they are to Earth.
Term
Define luminosity of the stars
Definition
luminosity measures the total amount of energy emitted by a star or other astronomical object per unit time.
Term
How are HR diagrams related to the luminosity and temperature?
Definition

Temp: hottest to coldest (left to right)

 

Luminosity: dim-brightest (bottom to top)

Term

Where are main sequence stars on the HR diagram?

 

Definition
Diagonally across the diagram. This is where most of the stars lie.
Term
Where do giant stars lie on the HR diagram?
Definition
at the very top middle of the diagram
Term
Where do the red giants lie on the HR diagram?
Definition
above the main sequence on the very end by the cold temperatures.
Term
Where do white dwards lie on the HR diagram?
Definition
below the main sequence in the hotter temperatures.
Term
What is a visual binary system?
Definition
A visual binary system is a system in which two separate stars are visible through a telescope that has an appropriate resolving power.
Term
What are spectroscopic binaries?
Definition
Spectroscopic binaries are systems in which the stars are so close together that they appear as a single star even in a telescope.
Term
What is an eclipsing binary system?
Definition

A binary star whose components pass in front of each other, thereby causing a regular eclipse of one of the stars.

 
Term
What does a light curve show?
Definition
shows the brightness of an object over a period of time.
Term
What are the more rare luminous stars?
Definition
the upper main sequence stars and the giants and supergiants.
Term
What did Copernicus do for astronomy?
Definition
Proved that the sun was the centre of the solar system, and that the sun, earth and the moon were all shaped like round balls. He is often regarded as the starting point of current astronomy and the defining
Term
What did Galileo do for Astronomy?
Definition

He Discovered that Earth was not the center of the solar system , Jupiter Has four moons and discovered the rings of Saturn.

Term
What is Keplers Third Law?
Definition
P2=A3
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