Exam 4 Flashcards
high mass stars are those that have a mass ______X that of the sun
8
If you see a supernova go off, that means…
new stars are forming in that galaxy
Neutron Stars
A core with remaining mass of 1.4-3 solar mass, composed of tightly packed neutrons
Black Holes
A remaining core with a mass of more than 3 solar mass. Will continue to collapse into an infinitely small location in space
Neutron stars are ______ solar mass
8-20
Black holes are ______Solar mass
20 or more
Inner (terrestrial) planets
Mercury, venus, Earth, Mars
Inner (terrestrial) Planets characteristics
small, rocky, very close to sun, have few moons, have no rings
the surface of Venus is completely hidden beneath…
thick atmosphere/clouds
Venus’ atmospheric pressure is
extremely high
Venus is covered with
gently rolling hill and numerous volcanoes
Jupiter is the ____ of the gas giant planets
LArgest
Jupiter is the ____planet in our solar system
Largest
Jupiter’s giant res spot is caused by…
high pressure storms in the atmosphere
How many moons does Jupiter have?
4 large moons and tens of smaller ones
Saturn has the most extensive…
ring system in our solar system
Saturns rings are composed of…
fragments of ice and ice-coated rock
Uranus’ atmosphere is …
hazy with a few clouds
Uranus’ tilt gives it…
very exaggerated seasons
Neptune has a ___ color
Brilliant blue
the Kuier belt is full of _______.
Mostly icy asteroids
the Kuier belt is _____X as wide as the asteroid belt?
20
Extra Solar Planets (exoplanets)
a planet outside of the solar system
Star has sufficient mass to …..
fuse hydrogen and helium
-M>80MJupiter
Brown Dwarf has insufficient mass to …
ignite hydrogen, but can undergo a period of Deutrium Burning
- 13 MJupiter< M < 80 MJupiter
Planet has insufficient mass to…
ignite hydrogen or deutrium
-M < 13 MJupiter
a sun like star is about a billion times brighter than…
the light it reflects from its planets
Direct imaging
imaging or spectroscopy of the planets themselves
Indirect imaging
deducing the pretense of planets through their effects not their host star
we can directly image exoplanets by….
using techniques to block out the host star’s light
Astrometry
detecting planets by measuring the change in a stars position in the sky
Motion affects ________.
waves
Doppler Effects____
the change in wavelength of radiation (light) due to the relative motion between the source and the observer along the line of sight
Astronomers use the Doppler Effect to learn about the ___ of stars, and other astronomical objects
radial (along the line of sight) motion
When something which is giving off light moves towards or away from you, _______.
the wavelength of the emitted light is changed or shifted
When the source of light is moving AWAY from the observer, the wavelength_______.
of the emitted light will appear to increase.
Redshift
when the source of light is moving away from the observer the wavelengths of the emitted light will appear to increase
When the source of light moving TOWARDS the observer the wavelength________.
of the emitted light will appear to decrease.
Blueshift
When the source of light is moving towards the observer the wavelength of the emitted light will appear to decrease
The doppler effect only happens for motion ______.
along the line of sight
The Doppler effect only happens if the object is emitting light is …
moving towards you or away from you
the amount of the doppler shift is proportional to the ______
Velocity
Objects move faster towards or away from you will exhibit a ______.
Larger blue or redshift
How do we measure these stars wobble?
1) observe the star moving with very high-resolution images
2) Use spectroscopy to measure the line-of-sight velocity shift due to the Doppler Effect
Transit
the passage of relatively small body across the disk of a larger of a larger body, usually a star or a planet, occulting only a very small area
The drake Equation
the number of civilizations in our galaxy with which communication might be possible
We see the Milky way galaxy…
edge on
three main regions of the Milky way
1) buldge
2) Disk
3) Halo
The milky way Galaxy is ____ light years across, but only ____ light years thick
100,000; 1,000
Stars in the disk all orbit in the _____ direction
same
Stars int eh bulge and halo have _____ orbits
Random
Intersteller Medium
the term for the material (gas and dust) which resides between the stars
LOW mass stars return gas to the Interstellar Medium by
blowing off their outer layers, which have been polluted from their fusion process due to some “dredge up”
Slow Neutron Capture
When low mass stars form new elements int heir outer layers during the supergiant phase
HIGH mass stars return material to the Interstellar Medium in two ways
1) steller winds blowing off much of the outer envelope before the supernova takes place
2) supernova return nearly all of the products of fusion to the ISM
Summary of the star-gas-star cycle
1) stars make new elements by fusion
2) dying stars expel gas and new elements producing hot bubbles
3) hot gas cools, allowing atomic hydrogen clouds to form
4) further cooling permits molecules to form, making molecular clouds
5) Gravity forms new stars in molecular cloud
Halo stars formed ____-.
first
Disk Stars formed______. later after halo stars
later after halo stars
Stars near out galactic center orbit
very quickly
stars orbiting very quickly indicated what?
that there is a lot of mass present that we cannot see
We study how galaxies grow by…
looking back in time using infinite speed of light
cosmology
the study of the overall structure and evolution of the universe
The Milky way resides in ____
the local group
Our local group is home to ______ galaxies
~50
our local group has a diameter of roughly _____.
~10 million light years
two types of galaxies
Spiral and Elliptical
Hubble Tuning Fork
relates all galaxy shapes and sizes
The most massive galaxies are ____.
elliptical galaxies
Elliptical galaxies make up ______% of the large galaxy population
15-20
Irregular galaxies are
not very common and typically star forming
Spiral galaxies are often found in
groups of galaxies
ellipitcal galaxies are often found in _____
huge clusters of galaxies
Galaxies in clusters are ______
always moving
If there was no dark matter galaxies would
be flying out of the galaxy
Dark matter does not _____
interact electromagnetically
Dark matter does not affect________
the nuclei of atoms
Dark matter interacts______
gravitationally
Hubble’s law
Velocity = Ho * distance
How do we measure distance?
we use the spectra of galaxies
The more cosmic dust, the _____ the light gets.
Redder
In order to find the most distant galaxies, we must…
Observe in the near-infrared
