Ceres

We just have to figure out how to recognize it.

If confirmed, ED-138 would join Pluto, Eris, Haumea, Makemake, and Ceres among the five dwarf planets officially recognized by the International Astronomical Union.

And with Ruben only beginning its 10-year survey of the sky, astronomers suspect there are plenty more discoveries ahead.

Now, let's leave the distant reaches of the solar system and turn our attention to some celestial sights we can actually see from our backyards.

Ai margini della sovranità gravitazionale del Sole orbitano i pianeti nani, corpi che non hanno completato la pulizia orbitale attorno alla propria traiettoria ma possiedono massa sufficiente per raggiungere l'equilibrio idrostatico di forma sferoidale.

Accanto a Cerere, incastonato nella fascia principale tra Marte e Giove, si dispiegano i mondi transnettuniani della fascia di Kuiper: Plutone con le sue cinque lune tra cui la maestosa Caronte, Eris, Haumea con la sua caratteristica forma allungata a fuso da rapida rotazione, e Makemake, accompagnati da migliaia di planetesimi ghiacciati che compongono la remota nube di Oort.

Il nostro sistema solare si rivela un laboratorio dinamico in perenne evoluzione, dove ogni luna e ogni corpo minore custodisce tessere fondamentali per decifrare l'origine della materia e della vita nell'universo.

Guardare a questi mondi significa preparare i passi delle future generazioni verso le stelle.

The objects above it on that list include Pluto, Eris, Haumea, and Makemake, which are four of the five dwarf planets the International Astronomical Union officially recognizes.

The fifth is Ceres, in the asteroid belt.

It's worth a quick reminder of what dwarf planet means, because the definition does the work in this story.

Under the IAU's 2006 rules, a planet orbits the sun, has enough gravity to pull itself into a round shape, and has cleared its orbital neighborhood of other material.

It became the first spacecraft to orbit an object in the main asteroid belt, and Vesta became the first stage of a mission unlike any previous planetary expedition.

Rather than making a single visit and leaving, Dawn would eventually travel onward to the dwarf planet Ceres.

The spacecraft had been designed to orbit both bodies sequentially, using its ion engine to reshape its trajectory after completing its work at Vesta for 14 months.

Dawn gradually changed its distance from the asteroid.

Details that had appeared as variations in telescopic light became individual geological structures allowing researchers to connect composition, terrain, and impact history across the entire body.

Dawn finally departed Vesta on September 5, 2012.

Its ion engine began another long acceleration, carrying the spacecraft onward through the asteroid belt toward Ceres, which it reached in March 2015.

The mission continued there for several more years, until Dawn exhausted the hydrazine used by its attitude control system.