SEF
Spacecraft event file.
Half the distance of an ellipse's maximum diameter, the distance from the center of the ellipse to one end.
A type of spiral galaxy which has a small, compact nucleus that is much brighter than the rest of the ...
A type of star which is believed to be surrounded by a thin envelope of gas, which is often indicated ...
A satellite that constrains the extent of a planetary ring through gravitational forces. Also known as a shepherd moon.
A Shooting star is a popular term for a meteor, which is a flash of light generated when a meteoroid ...