What are the Four Terrestrial Planets in Order?
Mercury, Venus, Earth, Mars
Given the names of the seven stages of birth of a one solar-mass star, be able to place them in proper sequence and place strong stellar winds and the start of nuclear fusion in the sequence. Know the total time for birth to the Main Sequence for stars of O-type, G-type, and M-type.
Stage 1 = giant molecular cloudStage 2 = dense core (cool, collapsing part of cloud)Stage 3 = accretion of protostarStage 4 = protostar (emits IR, blocked by accretion disk; accretion halted by proto-stellar winds)Stage 5 = pre-main sequence star (strong wind, tau tauri stage)Stage 6 = start of nuclear fusion of H HeStage 7 = main sequence (fuses H in core)
How are mass and luminosity of a star related?
More massive means brighter and hotter. A ten solar mass star has about ten times the sun's supply of nuclear energy. Its luminosity is 3000 times that of the sun.
List stages 8-13 of a Main Sequence star of less than 8 solar masses, including the two possible fates of such stars.
Stage 8 = (+He Flash), Red Giant, H fusing shell, while core shrinks, reheats until "flash"Stage 9 = He Fusion, He + He + He C in the core at 108k. Temperature rises, and luminosity drops, moves to horizontal branch of H—R diagram.Stage 10 = end of He fusion in the core, it shrinks and reheatsStage 11 = red giants (AGB), outer H-fusing, He-fusing shells grow, luminosity risesStage 12 = planetary nebula, outer shell of star expands to diffuse, escaping cloud. Core collapses to a hot, UV emitting object, makes nebula growStage 13 = white dwarf, core shrinks until electrons packed together
How do stars of mass greater than 8 solar masses evolve after they leave the Main Sequence?(The Lecture-Tutorial we did on this should help you organize your ideas)
They continue to have fusion in their core however eventually create iron, which is unable to be fused. The iron makes the star's mass increase, packing electrons into the core however not exerting energy. This will continue until the star becomes heavy enough that it collapses, resulting in a supernova.
What are Open Clusters and Globular Clusters? How does each one help us understand the life cycles of stars of different masses?
Open clusters are loosely bound groups of a few tens to a few hundred stars. They are found in spiral and irregular galaxies. Globular clusters are tight groups of hundreds to millions of stars which are gravitationally bound. They help understand the life cycles of stars between open clusters tend to hold younger stars due to their abundance of gas and dust. On the other hand, globular clusters are home to much older, dying stars.
What properties must a neutron star have to be observed by us as a pulsar?
For a neutron star to be seen as a pulsar, it must have very rapid rotation and a very strong magnetic field. As the star rotates, it would project a "beam" of radio waves that sweeps around the sky like a lighthouse. When that beam would be directly pointed at us, we would be able to observe a pulsar.
How can a black hole be detected, since nothing escapes from within the event horizon?
We can detect a blackhole through observing the way gravity and light behave. As a star is collapsing, the gravity strengthens which results in the bending of light and a redshift in light.
What are the dimensions and basic shape of a spiral galaxy like ours? Where are we in our galaxy? What are the other types and shapes of galaxies?
The basic dimensions and shape of our galaxy are 10^9 to 4 x 10^11 Msun. Our galaxy is a spiral shape, which are made up of mostly gas and dust throughout the branching arms. Along with our type, there are also elliptical galaxies which have a dense nucleus and very little other structure to them. They are found between 10^5 to 10^13 Msun.
What are the "yardsticks" (or "meter sticks") we use to measure distances on the galactic and intergalactic scales? [Hint: all of these are "standard candles;" they have known luminosity.]
The "yardsticks" we use to measure distances on galactic and intergalactic scales comes from a star's brightness. By looking at the visual and absolute magnitude of a star, we are able to calculate that star's distance.
What is the cosmological redshift? What does it tell us about the Universe?
Between 1912 and 1920, astronomers were starting to realize that all galaxies were redshifted, meaning that the lines the spectra were displaced towards longer wavelengths. When a redshift is seen, this tell us that the source of waves is moving away from us. Edwin Hubble would later measure distance by variable stars, plotted against velocity and found that the distance between galaxies is increasing, so that also means the universe is expanding.