A protoplanet is a large planetary embryo that originated within a protoplanetary disk and has undergone internal melting to produce a differentiated...

about direct interactions with planetary regoliths. Ceres is a surviving protoplanet that formed 4.56 billion years ago; alongside Pallas and Vesta, one of...

Theia (/ˈθiːə/) is a hypothesized ancient planet in the early Solar System which, according to the giant-impact hypothesis, collided with the early Earth...

gravitationally bound and can mimic protoplanets. In the case of GoHam b it is not clear if it is a protoplanet or just a disk fragment. JWST NIRCam...

AU, and again from 13 AU out to a few hundred AU, with evidence for a protoplanet forming at a distance of around 47 AU. Estimated to be less than 10 million...

asteroid to have been discovered, after Ceres, and is likely a remnant protoplanet. Like Ceres, it is believed to have a mineral composition similar to...

often called a primordial or proto-atmosphere, is an atmosphere of a protoplanet that forms by accretion of gaseous matter from the protoplanetary disk...

attracted each other, coalescing to form ever larger bodies. Hundreds of protoplanets may have existed in the early Solar System, but they either merged or...

condensed into the oceans, augmented by water and ice from asteroids, protoplanets, and comets. Sufficient water to fill the oceans may have been on Earth...

solar nebula as a group of planetesimals, the smaller precursors of the protoplanets. However, between Mars and Jupiter gravitational perturbations from Jupiter...

Telescope, as well as a 3rd unconfirmed one. PDS 70b was the first confirmed protoplanet to be directly imaged. The "PDS" in this star's name stands for Pico...

the mass of the asteroid belt. Vesta is the only known remaining rocky protoplanet of the kind that formed the terrestrial planets. Numerous fragments of...

dynamical friction between the protoplanet and the protoplanetary disk causes energy to be transferred from the protoplanet to the disk. This results in...

heaviest known M-type asteroid, and may be an exposed iron core of a protoplanet, the remnant of a violent collision with another object that stripped...

filaments cooled into numerous, tiny, solid planetesimals and a few larger protoplanets. This model received favorable support for about 3 decades, but passed...

distinct signature for each Solar System body. If Theia had been a separate protoplanet, it probably would have had a different oxygen isotopic signature than...

through mutual gravity, enormously aiding further growth into moon-sized protoplanets. Smaller bodies must instead rely on Brownian motion or turbulence to...

complex debris disk containing a large planet or brown dwarf and possible protoplanet. Two further star systems have been found to have planets. The constellation...

planets. Several protoplanet candidates have been suggested in the literature starting from 2014. Nonetheless, a particular protoplanet candidate detected...

the whole asteroid belt. It was thought to be the exposed core of a protoplanet, but recent observations cast doubt on that hypothesis. Psyche will be...

process, which continues for several million years, but after the forming protoplanet reaches about 30 Earth masses (ME) it accelerates and proceeds in a runaway...

Europa would also count geophysically, as well as perhaps the large protoplanet-asteroids Pallas and Vesta (though those are borderline cases). Among...

Sahara Desert in Algeria. It is believed to be a fragment of a chondritic protoplanet that is over 4.566 billion years old, and is believed to be the oldest...

in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt: Vesta and Ceres. In the fulfillment of that mission—the...

accretion is far more problematic. The escape velocity for the small protoplanets about 20 astronomical units (AU) from the center of the Solar System...

hypothesis suggests that the Early Earth collided with a Mars-sized protoplanet of the same orbit approximately 4.5 billion years ago in the early Hadean...

formed the Sun, and the dust grains collected together to form the first protoplanets. As the planets grew, some of them eventually accreted enough matter...

may be many protoplanets orbiting the star or each other, but over time many will collide, either to form a larger, combined protoplanet or release material...

ALMA showed sulfur monoxide representing an outflow from an embedded protoplanet. The position of the brightest emission coincides with a planet-carved...

Giant planet Mesoplanet Planemo Planet/Brown dwarf boundary Planetesimal Protoplanet Pulsar planet Sub-brown dwarf Sub-Neptune Toroidal planet Ultra-cool...