Astronomers from University of Chicago Using the James Webb Space Telescope, they discovered an exoplanet that radically changed the understanding of planets outside the solar system. The new object, named PSR J2322-2650b, has a mass similar to Jupiter but has unique properties, combining the characteristics of a planet and a strange cosmic body that scientists could not previously explain.
The results are published in Astrophysical Journal Letters.
The strange neighborhood of a pulsar
PSR J2322-2650b orbits a rapidly spinning neutron star or pulsar at an extremely close distance – just 1.61 million km from the pulsar. Under the influence of intense radiation and strong gravity, this planet is deformed, shaped like a lemon. Streams of energy and high-energy particles make conditions on the surface and in the atmosphere extremely harsh.
Michael Zhang of the University of Chicago, who led the study, said: “This planet orbits a completely unusual star; its size is equivalent to a city, although its mass is equal to that of the Sun.”
An atmosphere of surprise
The space telescope's main discovery was the chemical composition of PSR J2322-2650b's atmosphere. Instead of the usual water vapor or methane, scientists discovered a mixture of mostly molecular helium and carbon.
“This is a new type of atmosphere, the likes of which have never been seen before,” Zhang explains. “When we received the spectroscopic data, our first reaction was: 'What is this object?'”
Analysis revealed the presence of C₂ and C₃ molecules, as well as soot-like clouds. Under extreme pressure, the carbon inside the planet could condense into crystals, possibly even diamonds. These data are not specific to planets but also raise questions about existing models of the chemical composition of the atmospheres of massive objects.
A unique opportunity to observe the planet
A special feature of this system is that the pulsar is almost invisible to Webb's infrared devices. This gives astronomers a rare opportunity to observe the planet without being affected by the light emitted by the star.
“We obtained pure spectra, which are extremely rare for planetary systems,” said Stanford University graduate student Maya Beleznay.
According to her, this makes it possible for the first time to measure the composition of the planet's atmosphere with such precision without blurring the data due to starlight.
Mystery of origin
The main question arises: how could a planet with such an unusual atmosphere appear? Scientists believe that no known planet formation model explains the extreme richness of carbon and helium.
“It is difficult to imagine how such a composition could form naturally. This rules out conventional scenarios of planet formation,” Zhang said. “Carbon crystals rise to the surface and mix with helium, but then a process must occur to prevent oxygen and nitrogen from entering,” suggested Roger Romani of Stanford University.
Such a mechanism has yet to be confirmed, making this planet unique and completely unpredictable.
Significance for astronomy
PSR J2322-2650b raises questions about planetary classification. Its characteristics blur the lines between planets and stars and reveal that the Universe contains objects with extreme conditions previously thought impossible.
“This planet reminds us that we have only explored a small part of the universe. Each new discovery expands our horizons, and Webb gives us a tool for observations that were previously unattainable,” said Peter Gao of the Carnegie Earth and Planetary Sciences Laboratory.
Astronomers note that further observations of this system could help understand how the exotic atmosphere is formed, how pulsars and their satellites interact, and would also expand our understanding of the chemical processes that occur in extreme cosmic conditions.
“We are just beginning to unravel the mystery of this planet. PSR J2322-2650b shows that space is full of surprises, and new telescopes are opening doors to objects we never knew existed,” Zhang added.
