Astronomers are once again facing a mystery: the James Webb Space Telescope (JWST) has helped discover an exoplanet unlike any previously known world. The object, designated PSR J2322-2650b, orbits a pulsar and is notable not only for its unusual shape but also for an atmosphere whose composition puzzles even seasoned researchers.
The planet has a mass comparable to Jupiter, but its orbit takes it around a dead star—a pulsar emitting intense streams of radiation. Such systems are called ‘black widows’: the pulsar gradually destroys its companion, bombarding it with deadly rays. Yet it is the atmosphere and shape of PSR J2322-2650b that set it apart from all other known exoplanets.
Unlike the familiar spherical planets, this object is elongated, resembling a lemon or an American football. The reason is the colossal tidal forces generated by its proximity to the pulsar. The distance between the planet and its star is just 1.6 million kilometers—about one hundred times less than that between Earth and the Sun. As a result, PSR J2322-2650b completes a full orbit around the pulsar in just eight hours.
An atmosphere like no other
The most astonishing feature is the chemical makeup of the atmosphere. It is almost entirely devoid of the familiar water, methane, and carbon dioxide molecules found in other exoplanets. Instead, helium and molecular carbon dominate, especially in the rare forms of C2 and C3. Scientists note that nothing like this has been observed on any of the roughly 150 exoplanets whose atmospheres have been studied so far.
Temperatures on the planet’s day side reach 2,040 degrees Celsius, while on the night side they drop to 650. The planet is tidally locked to the pulsar, always showing the same face, much like the Moon does to the Earth. Under these conditions, experts calculate that carbon may condense into soot, eventually forming diamond rains that fall to the surface.
The absence of oxygen and nitrogen in the atmosphere raises questions about the planet’s origin. According to researchers, none of the existing models of planetary formation can account for such an unusual chemical composition. The theory that the planet is the remnant of a destroyed star is also unconfirmed, as nuclear reactions cannot produce carbon in such pure form.
The pulsar and its companion
The pulsar around which PSR J2322-2650b orbits belongs to the millisecond class—it spins at hundreds of rotations per second. Such objects form after the explosion of a massive star, when its core collapses to incredible density and begins spinning rapidly, emitting powerful streams of radiation.
Interestingly, it was the particular radiation profile of the pulsar that allowed the JWST to obtain such detailed data about the planet. The pulsar emits almost no infrared radiation, so the telescope wasn’t hindered by background glare, enabling scientists to analyze the satellite’s atmosphere in detail.
There have been previous cases in astronomical history where planets were discovered orbiting pulsars—the first exoplanets found in 1992 also circled such objects. However, none of them exhibited such unusual physical and chemical properties.
Theories and mysteries
Researchers hypothesize that such an exotic atmospheric composition may be linked to crystallization processes within the planet. According to one version, as the planet cools, its carbon- and oxygen-rich inner layers begin to crystallize, and pure carbon rises to the surface, mixing with helium. However, it remains unclear how oxygen and nitrogen have almost completely disappeared from the atmosphere.
Scientists admit they are currently unable to explain the origin of this object. None of the known scenarios for planet formation and the evolution of stellar remnants fit the case of PSR J2322-2650b. The discovery calls into question many established views about processes occurring in the extreme conditions of space.
The authors of the discovery note that such mysteries are a rare stroke of luck for science. Each new fact about this unusual planet could lead to a reassessment of theories on planetary system formation and the chemical evolution of the universe.
The future of research
In the coming years, astronomers plan to continue monitoring this system in an effort to uncover the secrets of its origin. Further research could reveal additional objects with similar characteristics, helping to determine just how unique PSR J2322-2650b is.
This breakthrough was made possible by the unique capabilities of the James Webb telescope, which can detect infrared radiation with unprecedented precision. This enables researchers to explore even the most remote and exotic corners of our galaxy.
In case you didn’t know, the James Webb Space Telescope is the largest and most expensive space telescope in history, launched in 2021. Its main mission is to study the early Universe, exoplanets, and the processes that shape stars and galaxies. Thanks to its high sensitivity and resolution, JWST has already made a series of groundbreaking discoveries, including the detection of unusual exoplanets and the analysis of their atmospheres. The telescope is jointly operated by NASA, ESA, and the Canadian Space Agency.
