Astronomy 2022 October 31-November 2

constantly leaking heat and light out into space, must make up for all energy lost or else they will cool and fade

core, envelope, photosphere, atmospheres

heat flows from regions of higher temperature to lower temperature, core-envelope-photosphere-space. As you move outward from the core, there is a decrease in temp, pressure and density, and you reach photospher

4 hydrogen to helium+gamma+neutrino. Helium core releases radiation and neutrinos, main sequence stars have hydrogen helium fusion taking place here

core, radiative zone, interface layer, convective zone

surface area of a sphere, amount of energy released, and Stefan Boltzmann constant equals this. Output of a typical main sequence star is 3.26 x 10^26

amount of energy radiated is the same everywhere. Emitted from main sequence stars

a way to transport energy into a star (dominant mechanism), in envelope, gamma radiation leaves the core and travels to this zone as photons

radiation. 250k years, OST photons emitted from core, hit an electron or atom within 1 mm (trillions of collisions) and gets scattered in different directions. Photons make it to the surface and radiate away after collisions and have lost a significant amount of energy

way to transport energy into a star, in envelope. Heat energy is carried from hotter regions below to cooler regions above by bulk flow of the gas and circulating convection flow

when they reach the top, gas gives up its heat to the cooler photosphere, cool gas sinks back to core, heats and expands and rises again, repeat. Creates local magnetic fields

mode of energy transfer is determined by temp, pressure and density. Higher (>1.5 solar masses, CNO fusion, 18m K), lower (proton proton fusion, 12m K, .5-1.5 solar masses), and low mass stars (<.5 solar masses, no radiation, proton proton fusion)

a way to transfer energy into a star, heat energy is passed from atom to atom (vibrating) in dense materials. Most efficient when density is high, energy transferred from hot to cold regions

part of the star you see with your naked eye. defined as the part of the body that reflects or emits light. At 5.8k K hydrogen gets an extra electron and absorbs/scatters photons (hydrogen atoms become ionized and photons can’t get out so they become opaque)

in envelope, 805 hydrogen, 19% helium, 1% other. Emits light in every part of the electromagnetic spectrum and visible from 400 to 750 nanometers. Small amounts of infrared, microwave, radio, and x ray and gamma radiation

Bubbling pattern seen in the photosphere, created by convective currents in the convective zone. Hot columns of rising gas, size of Arizona rising at 3k mph. Cool dark regions of sinking gas as well

the sun exhibits this because it is not a solid body. Rotation at the equator different from poles.

solar magnetic cycle lasts 22 years and flips every 11 years. Tied to magnetic cycle

Troposphere, stratosphere, mesosphere, thermosphere, exosphere
Absorbs visible/infra-red/microwave, to ultra violet, to x ray and gamma

dark, cooler regions in photosphere. Caused by overlapping of the suns magnetic field, interaction of plasma and magnetic fields, and magnetic field interacting with differential rotation. Occur in pairs with opposite magnetic poles

darker cooler regions on the sun 2000 degrees cooler, a part of sunspots

hotter brighter regions 1000 degrees hotter surrounding umbra, a part of sunspots

sun isn’t a solid body so it exhibits this. Rotation at the equator (24.8 degrees) is different than poles (34.8 degrees). Takes equator 25 days vs poles taking 35. Slower at the polar

tied to solar magnetic cycle. lasts 22 years and flips every 11 years Cycles from maximum (many sunspots) to minimum (no sunspots)

flips north and south magnetic poles every 11 years. tied to sunspot cycle. Butterfly diagram. Sunspots have north and south magnetic poles

next layer above photosphere, strong UV source. Thin, not as bright, visible during a total solar eclipse. Temperature 30k-60k K

chromospheric occurrence. Fingers of cool gas. Magnetically confined tubes of plasma, can extend 6.5k KM into the corona. Duration 5-15 minutes.

chromospheric occurrence. Violent explosions which release bright light, x rays and high energy particles. 5-10 minutes, temperatures 8.5m K. A trio was released April 2017

energy of 1 billion hydrogen bombs. ejects 10 billion tons of plasma per event

chromospheric occurrence. Arcs of gas extending millions of kilometers into the Corona. Not flames (the sun is not burning). Erupt or arcade

next layer above chromosphere. Heated by acoustics. Extends millions of km, temperature 3 million K, low density (1/1 billion of 1ATM). Visible during total solar eclipse.

high energy particles flowing out of the star. 450 km/s, 92% ionized hydrogen, 8% helium

dark areas escaping solar wind

hot ball of plasma influenced by magnetic fields. 80% hydrogen 19% helium. Core hydrostatic equilibrium. Radiative zone, convective zone, photosphere surface. Thermal equilibrium, luminosity, life spans. Classified by spectral and luminosity classes and plotted on HR diagram.