When Ego was killed, Peter Quill lost his connection to the light that gave him powers presented in Guardians of the Galaxy Vol. 2. Even the director, James Gunn, revealed in a now-deleted Tweet that Peter isn't getting those powers back.
Peter Quill is semi-immortal in the comics thanks to his hybrid Human/Spartax physiology and the fact that he stole the source of power from the gods. This means that he ages much more slowly than a regular human being. In the MCU, however, Star-Lord is not immortal.
In his new role, Peter can survive in space, fly faster than the speed of light, and generate a personal force field. His other abilities include being able to recover from injuries quickly, super human strength, and universal language translation.
Peter Jason Quill was born in 1980 to Meredith Quill and Ego, making him a hybrid of human and Celestial. His conception was all part of a plot set up by his father to produce a second Celestial, whose power he could use to complete the Expansion, which involved assimilating millions of worlds into Ego's very being.
In Guardians of the Galaxy Vol. 2, Ego the Living Planet, Peter Quill / Star-Lord's biological father, is a Celestial who controls a humanoid avatar to travel the universe. His planetary form is a living extension of his Celestial consciousness.
When Ego was killed, Peter Quill lost his connection to the light that gave him powers presented in Guardians of the Galaxy Vol. 2. Even the director, James Gunn, revealed in a now-deleted Tweet that Peter isn't getting those powers back.
Quill did not lose his Celestial power, he lost his connection to Ego. His connection to Ego served similar to Thor's connection to Mjornir; it helped him channel and use his power before he actively knows how to do so.
The Gods are below celestials. Celestials and the Pillars of Reality (Eternity, Infinity, Entropy and Death) are the top dogs and creators of the universe. They are omnipotent. The pantheon gods are just super-powered beings that were or are worshipped by people, that's all.
Knowhere was one of two celestial objects orbiting Battleworld, considered to be its moon; the other was Johnny Storm, its sun. Knowhere was the decapitated head of a Celestial, said to have been slain by God Emperor Doom to protect Battleworld, and it remained orbiting the planet as a reminder of Doom's power.
Peter Quill AKA Star-Lord's Shield Of Spartax
Star-Lord's Mega Ability is the Shield of Spartax. As the name suggests, it creates a shield around Star-Lord making him invulnerable for a limited amount of time.
We know from Guardians of the Galaxy 2 that Celestials are god like beings. Odin seems to possess a power far beyond any other Asgardian. He was a celestial that, unlike Peter's dad, used his power to birth a race of people who each carried a bit of his power within them.
In the comics Quill's Spartax heritage ensured he'd live longer than most humans but didn't make him immortal.
After all, It's because some fans thought that Galactus is a celestial, but no. Galactus is not a Celestial. Both are considered space gods threatening to destroy the earth. Both are giants with unimaginable power and have very similar wardrobes in the comics.
Ego was a Celestial, a primordial and powerful being, and the biological father of Peter Quill and Mantis.
Having a celestial parent doesn't make you a eternal. Peter's dad is a celestial, so Peter is technically a half celestial. Eternals are basically enhanced humans with superpowers. They are the product of the celestials' genetic experiments, not their children.
While most Celestials possess extraordinary power, Gamiel is the weakest of all of them. He is the same size as that of the Hulk and is the youngest of all Celestials. Gamiel got the moniker “Manipulator” because he caused the events that led to the 4 million year Kree-Skrull war.
Apocalypse states that the Hulk's power/energies can challenge or possibly even overcome the celestials themselves.
This is why Wanda's powers are so strong, but her genetic disposition - which may be the beginning of the development of mutants - also accentuates her abilities. Besides, Wanda's anger has increased her power level, and WandaVision just revealed that she now could hold her own against a Celestial.
While the Celestials are known to be so strong that they can create and destroy planets, there is another major cosmic entity that can take on a Celestial in battle. Galactus is an immortal entity that devours entire planets.
The heroes try to stop the Progenitor several times, but their efforts are futile, as a Celestial is simply too powerful to be harmed or killed. However, this is not necessarily true. In fact, Thor owns a weapon that was created with the exact purpose of killing Celestials, and he used it effectively in the past.
As the leader of the Celestials “Host” form, Arishem the Judge travels to Earth over the course of four visits to judge whether they are worthy of existence.
Unlike his MCU counterpart who ultimately flubbed The Avengers efforts to takedown of Thanos, Peter Quill was able to defeat Thanos in the comics.
Personally, Thanos is physically and mentally superhuman, capable of overpowering the Hulk and the Asgardians that he casually wipes out. Taken as individuals, Thanos is easily overpowered, but with all massed resources on both sides, he is marginally capable of overcoming Ego.
4? Director James Gunn previously made it clear that Vol. 3 will be the last we see of this particular line-up of Guardians.