15: The Sun - A Garden-Variety Star

Question 1

an area on the Sun where magnetic fields are concentrated - where sunspots, prominences, flares, and CMEs all tend to occur

Answer 1

active region

Question 2

light radiated by atoms and ions in the ionosphere excited by charged particles from the Sun, mostly seen in the magnetic polar regions (northern and southern lights)

Answer 2

aurora

Question 3

the part of the solar atmosphere that lies immediately above the photospheric layers

Answer 3

chromosphere

Question 4

the outer (hot) atmosphere of the Sun

Answer 4

corona

Question 5

a region in the Sun’s outer atmosphere that appears darker because there is less hot gas there

Answer 5

coronal hole

Question 6

a solar flare in which immense quantities of coronal material (mainly protons and electrons) is ejected at high speeds (500–1000 kilometers per second) into interplanetary space

Answer 6

coronal mass ejection (CME)

Question 7

the phenomenon that occurs when different parts of a rotating object rotate at different rates at different latitudes

Answer 7

differential rotation

Question 8

the rice-grain-like structure of the solar photosphere - produced by upwelling currents of gas that are slightly hotter, and therefore brighter, than the surrounding regions, which are flowing downward into the Sun

Answer 8

granulation

Question 9

a period during the seventeenth century when the number of sunspots seen throughout the solar cycle was unusually low

Answer 9

Maunder Minimum

Question 10

the region of the solar (or stellar) atmosphere from which continuous radiation escapes into space - boundary where Sun becomes opaque and past which we cannot see

Answer 10

photosphere

Question 11

a bright region of the solar surface observed in the light of some spectral line

Answer 11

plage

Question 12

a hot ionized gas, with atoms stripped of electrons

Answer 12

plasma

Question 13

a large, bright, gaseous feature that appears above the surface of the Sun and extends into the corona

Answer 13

prominence

Question 14

a sudden and temporary outburst of electromagnetic radiation from an extended region of the Sun’s surface

Answer 14

solar flare

Question 15

a flow of hot, charged particles leaving the Sun

Answer 15

solar wind

Question 16

large, dark features seen on the surface of the Sun caused by increased magnetic activity

Answer 16

sunspot

Question 17

the semiregular 11-year period with which the frequency of sunspots fluctuates

Answer 17

sunspot cycle

Question 18

the region in the Sun’s atmosphere where the temperature rises very rapidly from the relatively low temperatures that characterize the chromosphere to the high temperatures of the corona

Answer 18

transition region

Question 19

the number of Earths that could fit the volume of the Sun

Answer 19

1.3 million Earths

Question 20

region above the Sun’s core that slowly transports light from the core through radiation

Answer 20

radiative zone

Question 21

outermost layer of solar interior that transports energy from radiative zone to the surface through convection cells

Answer 21

convection zone

Question 22

NASA space mission sent to investigate the transition region and why its sharp increase in temperature occurs

Answer 22

Interface Region Imaging Spectrograph (IRIS)

Question 23

inner, darker core of a sunspot

Answer 23

umbra

Question 24

lighter region of a sunspot that surrounds the umbra

Answer 24

penumbra

Question 25

period at which the number of observable sunspots is the greatest (occurs every 11 years on average) - more than 100 spots can be seen at once

Answer 25

sunspot maximum

Question 26

splitting of spectral lines in the presence of a magnetic field - used to measure solar magnetic field

Answer 26

Zeeman effect

Question 27

mechanism that converts kinetic energy into electricity - churning of plasma in Sun’s interior that generates its magnetic field

Answer 27

dynamo

Question 28

field of research predicting the effects of solar storms on Earth

Answer 28

space weather