Researchers from UCLA and Macau University of Science and Technology
The results of the study show that the cometsomewhat smaller than previously assumed by French scientists, but it remains the largest known comet. The previous record was held by C/2002 VQ94 with a core diameter of about 100 km.
Largest comets. Source: NASA, ESA, Zena Levy
Comet C/2014 UN271 was discovered by astronomersPedro Bernardinelli and Gary Bernstein in archival images from a dark energy study at the Cerro Tololo Inter-American Observatory in Chile. According to NASA, the first random observations were obtained in November 2010, when the comet was at a distance of 4.8 billion km from the Sun (about 32 AU).
Now the distance has been reduced to 3.2 billion km,scientists note that the comet falls almost perpendicular to the plane of the solar system at a speed of 35.5 thousand km / h. At this distance, the temperature is about -210°C. However, this is enough for the gases on the surface to sublimate and form a dusty coma.
Hubble data was needed to distinguishsolid core from the dust shell surrounding it. The comet is currently too far away for the telescope to visually discern its nucleus. Instead, the Hubble data shows a bright burst of light at the comet's location.
Researchers have formed a computer modelcoma surrounding the nucleus, and adjusted the parameters so that it matches the images of the telescope. After that, the simulated shell was removed to estimate the size of the kernel.
From left to right: Hubble observations, the coma model, and the nucleus cleared of the dust cloud. Source: NASA, ESA, Man-To Hui, David Jewitt
Scientists compared the obtained brightness of the comet's nucleus withearly observations with the ALMA telescope in Chile. The researchers note that the data obtained are very close, but their results show that the surface of the core is much darker.
Comet Bernardinelli-Bernstein is moving alongelliptical orbit, making a complete revolution in about 3 million years and moving away from the Sun by almost half a light year. C/2014 UN271 has been moving towards the Sun for more than 1 million years. Astrophysicists note that it comes from the alleged place where trillions of comets form - the Oort Cloud.
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