21: Birth of Stars and Discovery of Planets Outside the Solar System

Question 1

a planet orbiting a star other than our Sun

Answer 1

exoplanet

Question 2

large, cold interstellar clouds with diameters of dozens of light-years and typical masses of 105 solar masses - found in the spiral arms of galaxies, these clouds are where stars form

Answer 2

giant molecular clouds

Question 3

luminous knots of gas in an area of star formation that are set to glow by jets of material from a protostar

Answer 3

Herbig-Haro (HH) object

Question 4

a planet that is intermediate between the largest terrestrial planet in our solar system (Earth) and the smallest jovian planet (Neptune); generally have sizes between 2.8 and 4 times Earth’s size

Answer 4

mini-Neptune

Question 5

a very young star still in the process of formation, before nuclear fusion begins

Answer 5

protostar

Question 6

the outflow of gas, sometimes at speeds as high as hundreds of kilometers per second, from a star

Answer 6

stellar wind

Question 7

a planet larger than Earth, generally between 1.4 and 2.8 times the size of our planet

Answer 7

super-Earth

Question 8

when one astronomical object moves in front of another - can indicate the presence of an exoplanet when it moves in front of its star

Answer 8

transit

Question 9

cold, dense regions within molecular clouds with typical masses of 50 to 500 times the mass of the Sun

Answer 9

clumps

Question 10

colder, denser regions within clumps of molecular clouds that are the embryos of stars

Answer 10

cores

Question 11

protostar that has accreted almost all of its available material and has nearly reached its final mass - only stars less than or equal to Sun’s mass go through this phase

Answer 11

T Tauri

Question 12

jovian exoplanets orbiting very closely to their star

Answer 12

hot Jupiters