EngliSea
>
A
>
astronomy
>
stellar classification
Songs in Easy English
•
neutron star
→ pulsar
20660#20665
SIBLINGS
CHILDREN
20665
•
stellar classification
-- specroscopy, Henry Draper, Annie Jump Cannon, Hertzsprung-Russel, deplete, luminous, luminosity, Edward, mnemonic
20660#14595
SIBLINGS
CHILDREN
14595
-