“Since both types of molecules are subject to the same dynamic forces such as winds, this implies that hydrogen cyanide is affected by other mechanisms,” Ladislav Rezac said. In the region below the aurorae, however, the research team found an unexpected anomaly: There, the measurements show significantly less hydrogen cyanide than expected. Compared to older studies based on measurements from other ground-based telescopes, these data offer a significantly higher spatial resolution.Īs the analyses now accurately demonstrate, since the impact of comet Shoemaker-Levy 9 in 1994, both types of molecules have similarly distributed widely in Jupiter's atmosphere and now also populate extended altitudes. Using 2017 observations from the European Southern Observatory's Alma observatory in Chile's Atacama Desert and the International Gemini Observatory in Hawaii, the research team has now been able to closely examine the distribution of carbon monoxide and hydrogen cyanide in Jupiter's atmosphere. "We believe that the molecules the comet introduced into Jupiter's atmosphere nearly 30 years ago can help us better understand what's going on in the auroral region," said Ladislav Rezac. Last year, for example, a team of researchers that included two other scientists from the Max Planck Institute for Solar System Research in addition to Paul Hartogh reported stable stratospheric winds blowing beneath the aurora. "Jupiter's auroras have long fascinated researchers studying the dynamics and chemistry of Jupiter's atmosphere," said Paul Hartogh from the Max Planck Institute for Solar System Research. In addition, Jupiter's auroras - unlike those of Earth - are a permanent phenomenon, in part due to constant influx of particles originating from the violent volcanic eruptions of Jupiter's moon Io. However, Jupiter's magnetic field is about twenty times stronger than Earth's the auroras glow in all wavelengths ranging from infrared to X-rays. On Jupiter, too, an interplay of charged particles, magnetic field and atmosphere produces the aurora. As a result, they emit light of different wavelengths, producing the diffuse glow in shades of green, blue and, more rarely, red.
When, in phases of strong solar activity, high-energy solar wind particles travelling along the field lines of Earth’s magnetic field reach the atmosphere, molecules are ionized at a height of 100 to 1000 kilometers. (By comparison, Earth has a diameter of about 12,700 kilometers.) On a much smaller scale, this phenomenon is also known to occur on Earth. These are the scene of its massive auroras, which cover an area more than 40,000 kilometers in diameter. The research team mapped the entire planet in this way capturing in high resolution also the polar regions of Jupiter. The 2017 measurements, which researchers led by the University of Bordeaux have now analyzed and are publishing today, trace the distribution of entrained carbon monoxide and hydrogen cyanide with unprecedented accuracy. Because these molecules remain stable for many decades, they offered researchers a unique opportunity: over many years, scientists could observe how the molecules spread across Jupiter, providing valuable insights into the winds and chemical reactions in the gas giant's atmosphere. Further measurements showed that the comet introduced numerous types of molecules into Jupiter's atmosphere, such as carbon monoxide, carbon dioxide, water, and hydrogen cyanide, which were previously not native to the planet. In images taken by the Hubble Space Telescope, for example, the locations of the impacts appear as distinctive, black, cloud-like formations. In July 1994, the 21 fragments previously constituting comet Shoemaker-Levy 9 plunged into Jupiter offering powerful telescopes on Earth and in space an unprecedented view of such a unique event and its effects. © NASA, ESA, Jupiter ERS Team image processing by Ricardo Hueso (UPVEHU) and Judy Schmidt
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