Stars
What is a HII region?
Glowing cloud of ionized gas and massive stellar nursery for new stars
What is a magnetar?
A pulse of magnetic energy escaping from a neutron star
Three galaxies we talked about
Three of the following:
Spiral, Elliptica, Irregula, Lenticular, Quasars, Blazars
How do we observe molecular clouds?
Infrared light
What is Hubble's Law?
It states that the further a galaxy is, the faster it moves away from us
What is a planetary nebulae?
Glowing cloud of ionized gas and shed by dying intermediate-mass stars, with white dwarfs at the core
What is a pulsar?
Visible light only found emitting near the poles of a neutron star as it spins
How is a spiral galaxy different from an elliptical one?
Spiral galaxies: have flat, rotating disks with arms full of young, blue stars and gas
Elliptical galaxies: are 3D, smooth, oval-shaped blobs of mostly old, reddish stars with little dust or gas
What is a molecular cloud?
Photons traveling through ISM that is not fully absorbed or emitted
Results in dimming of stars that appear red
What is the Chandresakhar limit?
The max mass (10 solar masses) a white dwarf can have before it collapses into a supernovae or black hole
What is the difference between the PPC & CNO cycle?
PPC - Primary energy source for small stars but can be found in massive stars
CNO - Primary energy source for massive stars
Where do we believe cosmic rays come from?
From positrons and anti matter or supernovas
They are hard to study due to Earth's magnetic field skewing them
How is a spiral galaxy different from an irregula one?
Spiral galaxies: have flat, rotating disks with arms full of young, blue stars and gas
Irregular galaxies: lacks a defined shape, with no arms or bulge, are rich in gas and active star formation, containing both young and old star
What is our local fluff?
A gas cloud we are floating through and has a higher average temperature than our local bubble
What is the first evidence of the big bang theory?
Inflation - The universe is expanding, galaxies are moving away from us, and they are red shifting
What causes and what happens during the helium flash?
3 He fuses to create a carbon nucleus (the triple-alpha process), which causes a large burst of energy (helium flash), increasing luminosity greatly
What happens after the supernova stage?
The core of the exploded star leaves behind either
1) an ultra-dense neutron star if the star was smaller than 3 solar masses
2) a black hole if the star was bigger than 3 solar masses
How is a spiral galaxy different from an lenticular one?
Spiral galaxies: have flat, rotating disks with arms full of young, blue stars and gas
Lenticular galaxies: have a central bulge and disk but lack spiral arms, with older stars and little ongoing star formation
What is our local bubble?
Stars and things closest to us, and has a high concentration of atoms
What is the second evidence of the big bang theory?
Cosmic Microwave Background Radiation (CMB) - It's electromagnetic energy leftover from the Big Bang
What is a difference/similarity between gravitational red shifting and interstellar reddening?
Similarity:
Make stars appear redder
Difference:
GRD - wavelengths are pulled back by the gravity of the star, stretching it and making it become red
IR - wavelengths pass through a gas cloud, scattering the blue light's wavelength and leaving the red ones to be seen by us.
What are the two types of supernovae?
Type IA - a white dwarf absorbs energy from the other star in its binary system, collapses, and explodes.
Type II - is a massive star (8+ solar mass) that exhausts its nuclear fuel, it's core collapses, and results in a massive explosion
How is a spiral galaxy different from a quasar one?
Spiral galaxies: have flat, rotating disks with arms full of young, blue stars and gas
Quasar galaxies: distant galaxies with extremely luminous cores, powered by supermassive black holes, releasing tremendous energy that can outshine their entire host galaxy
What does it mean when a galaxy is red-shifting?
When a galaxy appears red (emitting red light), it is because it is moving away from us
What is the third evidence of the big bang theory?
Dark energy - Not understood well, was believed the matter of the Universe would slow its rate of expansion (mass creates gravity, which creates pull, which slows expansion) BUT supernovae observations showed that the expansion of the Universe is accelerating (something, unlike matter and ordinary energy, is pushing the galaxies apart)