AssetID: 55341949
Headline: RAW VIDEO: Astronomers discover bizarre lemon-shaped planet in scientific first
Caption: Astronomers have discovered one of the most bizarre planets they have ever seen - a lemon-shaped world that orbits a pulsar. The planet PSR J2322-2650b’s shape is distorted by the pulsar – a rapidly spinning neutron star left behind after a supernova explosion. Pulsars emit narrow beams of electromagnetic radiation that sweep through space as they rotate, flashing at intervals ranging from milliseconds to seconds. These pulses are only visible from Earth when the beams are pointed directly towards us, much like the beam from a lighthouse. The millisecond pulsar at the heart of this system emits mostly gamma rays and other high-energy particles, which are invisible to the James Webb Space Telescope’s infrared instruments. Crucially, the pulsar itself does not overwhelm observations, allowing scientists to study the planet in exceptional detail throughout its orbit. “This system is unique because we are able to view the planet illuminated by its host star, but not see the host star at all,” said Maya Beleznay, a third-year PhD candidate at Stanford University in California, who helped model the planet’s shape and orbital geometry. “So we get a really pristine spectrum. And we can study this system in more detail than normal exoplanets.” The planet orbits what researchers describe as an extreme stellar remnant. “The planet orbits a star that's completely bizarre - the mass of the Sun, but the size of a city,” said the University of Chicago’s Michael Zhang, the principal investigator on the study. “This is a new type of planet atmosphere that nobody has ever seen before. Instead of finding the normal molecules we expect to see on an exoplanet - like water, methane, and carbon dioxide - we saw molecular carbon, specifically C3 and C2.” Molecular carbon is highly unusual in planetary atmospheres. At the extreme temperatures measured on this world - ranging from about 1,200 degrees Fahrenheit on the night side to 3,700 degrees Fahrenheit on the day side - carbon would normally bond with other elements such as oxygen or nitrogen. Its presence suggests an atmosphere almost entirely lacking those elements. Of the roughly 150 planets studied in detail both inside and beyond the Solar System, none have previously shown detectable amounts of molecular carbon. The planet is extraordinarily close to its host, orbiting at a distance of just one million miles. By comparison, Earth is about 100 million miles from the Sun. The tight orbit means a year on this world lasts just 7.8 hours. The intense gravitational pull of the pulsar is distorting the Jupiter-mass planet into an elongated, lemon-like shape. The system is thought to belong to a rare class known as “black widow” systems, in which a rapidly spinning pulsar is paired with a much smaller companion. In typical cases, powerful radiation and winds from the pulsar gradually strip material from its partner, eventually destroying it. However, this example is unusual because the companion is classified as an exoplanet rather than a star. The International Astronomical Union defines an exoplanet as a body with less than 13 times the mass of Jupiter that orbits a star, brown dwarf or stellar remnant, including pulsars. Of the approximately 6,000 exoplanets discovered so far, PSR J2322-2650b is the only one resembling a gas giant with characteristics similar to a “hot Jupiter” while orbiting a pulsar. Only a handful of pulsars are known to host planets at all. “Did this thing form like a normal planet? No, because the composition is entirely different,” said Zhang. “Did it form by stripping the outside of a star, like ‘normal’ black widow systems are formed? Probably not, because nuclear physics does not make pure carbon. It's very hard to imagine how you get this extremely carbon-enriched composition. It seems to rule out every known formation mechanism.” One possible explanation has been suggested by study co-author Roger Romani, of Stanford University and the Kavli Institute for Particle Astrophysics and Cosmology. “As the companion cools down, the mixture of carbon and oxygen in the interior starts to crystallize,” said Romani. “Pure carbon crystals float to the top and get mixed into the helium, and that's what we see. But then something has to happen to keep the oxygen and nitrogen away. And that's where the mystery come in. “But it's nice to not know everything,” said Romani. “I'm looking forward to learning more about the weirdness of this atmosphere. It's great to have a puzzle to go after.”
Keywords: feature,photo,video,lemon,planet,space,james webb space telescope,science
PersonInImage: This artist’s concept animation shows what the exoplanet PSR J2322-2650b may look like. Gravitational forces from the much heavier pulsar it orbits are pulling the Jupiter-mass world into this bizarre lemon shape.