protoplanetary
Adjective
Meaning
protoplanetary (not comparable)
(astronomy, planets) Of or pertaining to a protoplanet.
protoplanetary (not comparable)
Relating to a stage in the life of a red giant star or its protoplanetary nebula during the star's final stages of life
Examples
In the early stages of a solar system's formation, these protoplanetary disks cause dynamical friction, causing young planets to spiral inwards rather than complete perfect, closed ellipses.
In 2007, observations showed a protoplanetary disc around the companion, Mira B. This disc is being accreted from material in the solar wind from Mira and could eventually form new planets.
Like other members of the Kuiper belt, Pluto is thought to be a residual planetesimal ; a component of the original protoplanetary disc around the Sun that failed to fully coalesce into a full-fledged planet.
Stellar planetary systems A protoplanetary disk with a cleared central region.
Study of the number of proplyds (protoplanetary discs, clumps of gas in nebulae from which stars and planetary systems are formed) indicates that the number of stars in the galaxy should be several orders of magnitude higher than what we know about.
Thus the dust is more likely created by a debris disk around Vega, rather than from a protoplanetary disk as was earlier thought.