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Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Asteroid Hygia may actually be the smallest dwarf planet in the solar system

Asteroid Hygia may actually be the smallest dwarf planet in the solar system



  Hygia sphere / VLT image

A new Hygia sphere / VLT image that may be the smallest dwarf planet on the solar system so far. Being an object in the main asteroid belt, Hygius immediately satisfies three of the four requirements for being classified as a dwarf planet: orbits the sun, is not a moon, and unlike the planet, it has not cleared the environment around its orbit. The ultimate requirement is that it be of sufficient mass that its own gravity pulls it into a roughly spherical shape. Here's what VLT observations for Hygiea have revealed now. Credit: ESO / P. Vernazza et al. / MISTRAL algorithm (ONERA / CNRS)

Astronomers using the very large telescope (VLT) SPHERE tool ESO have revealed that asteroid hygiene can be classified as a dwarf planet. The site is the fourth largest in the asteroid belt after Ceres, Vesta and Palace. For the first time, astronomers observed Hygius in a high enough resolution to study its surface and determine its shape and size. They found that Hygius was spherical, potentially taking the crown from Ceres as the smallest dwarf planet in the solar system.

As an object in the main asteroid belt, Hygia immediately meets three of the four requirements to be classified as a dwarf planet: it orbits the Sun, is not a moon, and, unlike the planet, has not cleared the neighborhood around its orbit. The ultimate requirement is that it has enough mass for its own gravity to pull it into a roughly spherical shape. This was revealed by VLT's observations of Hygiea.

"Thanks to the unique ability of the SPHERE tool on VLT, which is one of the most powerful imaging systems in the world, we could solve the form of Hygia, which turns out to be almost spherical, "Says lead researcher Pierre Vernaca of Laboratoire d & # 39; Astrophysique de Marseille in France. "Thanks to these images, Hygia can be classified as a dwarf planet, by far the smallest in the solar system."

The team also uses the observations of SPHERE to limit the size of Hygia by placing its diameter just over 430 km. Pluto the most famous of the dwarf planets, has a diameter of close to 2400 km, while Ceres is about 950 km in size.

Surprisingly, observations also revealed that Hygius lacked the very large impact crater that scientists expected to see on its surface, the team report in a study published today by Nature Astronomy . Hygiea is a major member of one of the largest families of asteroids, with close to 7,000 members, all of which originate from the same parent body. The astronomers expected the event that led to the formation of this large family to leave a large, deep imprint on Hygia.

  SPHERE images of Hygia, Vesta, and Ceres

New observations with ESO's SPHERE tool on a very large telescope have revealed that the surface of Hygia lacks the very large crater that scientists expect to see on its surface. As it was formed by one of the biggest strikes in the history of the asteroid belt, they expected to find at least one large, deep pool similar to that of Vesta (bottom right in the center panel).
The new study also found that Hygia is spherical, potentially taking the Ceres crown as the smallest dwarf planet in the solar system. The team uses SPHERE's observations to limit the size of the Hygiea, placing its diameter just over 430 km, while Ceres is approximately 950 km in size. Credit: ESO / P. Vernazza et al., L. Jorda et al. / MISTRAL algorithm (ONERA / CNRS)

"This result came as a real surprise as we were expecting a large pool of impact, as is the case with Vesta," says Vernaca. Although astronomers observe the surface of Hygia with a coverage of 95%, they can only identify two unambiguous craters. "Neither of these two craters could be caused by a shock originating from asteroids of the Hygia family, whose volume is comparable to that of a 100 km site. They are too small, ”explains study co-author Miroslav Broz of the Astronomical Institute at Charles University in Prague, Czech Republic.

The team decided to investigate further. Using numerical simulations, they concluded that the spherical shape of Hygia and the large asteroid family were probably the result of a large front collision with a large projectile between 75 and 150 km in diameter. Their simulations show this violent impact, thought to have taken place about 2 billion years ago, completely destroys the parent body. After the leftover pieces came together again, they gave Hygia their round shape and thousands of accompanying asteroids. "Such a collision between two large bodies in the asteroid belt has been unique over the last 3-4 billion years," says Assoc. a student at the Charles University Astronomical Institute, who also participated in the study.

The study of asteroids in detail is possible thanks not only to advances in numerical calculations, but also to more powerful telescopes. "Thanks to VLT and the new generation of SPHERE Adaptive Optical Instrument, we now map major belt asteroids with unprecedented resolution, closing the gap between Earth mission observations and interplanetary missions," Vernaca concludes.

More information

This study is presented in a paper that will appear in Natural Astronomy on October 28th.

The team is composed of P. Vernaca (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille, Marseille, France)), L. Yord (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille , Marseille, France), P. Schevecek (Institute of Astronomy, Charles University, Prague, Czech Republic), M. Brož (Institute of Astronomy, Charles) University, Prague, Czech Republic), M. Viikinkoski (Mathematics and Statistics, University of Tampere) , Tampere, Finland), J. Hanush (Institute of Astronomy, Charles University, Prague, Czech Republic), B. Kerry (Université Côte d & # 39; Azu r, Observatoire de la Côte d & # 39; Azur, CNRS, Laboratoire Lagrange, Nice, France), A. Drouard (Aix Marseille Université, CNRS, Lab oratoire d & # 39; Astrophysique de Marseille, Marseille, France), M. Ferrais (Space Science, Technology and Astrophysics Research Institute, University of Liège, Liège, Belgium), M. Marset (Department of Earth, Atmosphere and Planet Sciences, MIT Cambridge, MA, USA), F. Marches (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille, Marseille, France, and SETI Institute, Carl Sagan Center, Mountain View, USA) , M. Birlan (Observatory Paris, Paris, France), E. Podlewska-Gaca (Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University, Poznan, Poland and Institute of Physics, University of Szczecin n, Poland), E. Jechin (Research Institute of Space Sciences, Technology and Astrophysics, University of Liège, Liège, Belgium), P. Barzak (Institute of Astronomical Observatory, Faculty of Philosophy ysics, University of Poznań, Mitznitzowicz) , G. Dudzinski (Institute for Astronomical Observatory, Faculty of Physics, Adam Mickiewicz University, Poznan, Poland), J. Bertier (Observatory of Paris, Paris, France), J. Castillo-Rogez (Jet Propulsion Laboratory, California Institute of Technology) , Pasadena, CA, USA), F. Cipriani (European Space a , ESTEC – Scientific Support Office, Netherlands), FF Colas (Observatoire de Paris, Paris, France), F. DeMeo (Ministry of Earth, Atmospheric and Planetary Sciences, MIT, Cambridge, MA, USA), C. Dumas ( TMT Observatory, Pasadena, USA), J. Durech (Institute of Astronomy, Charles University, Prague, Czech Republic), R Fetik (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille, Marseille, France and ONERA, French Aerospace laboratory, Chatillon Cedex, France), T. Fusco (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille, Marseille, France and ONERA, French Aerospace Laboratory, Chatillon Cedex, France), J. Grice (Université Côte # 39; Azur, Observatoire de la Côte d & # 39; Azur, CNRS, Laboratoire Lagrange, Nice, France and Open University, School of Physical Sciences, The Open University, Milton Keynes, UK), M. Kaasalainen (Mathematics & Statistics, Tampere University, Tampere , Finland), A. Kryszczynska (Institute for Astronomical Observatory, Faculty of Physics, Adam Mickiewicz University, Poznan, Poland), P. Lamy (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille), Marseille, France Le Coroller (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille, Marseille, France), A. Marciniak (Institute of Astronomical Observatory, Faculty of Physics, Adam Mickiewicz University, Poznan, Poland), T. Michalov Ki (Institute of Astronomical Observatory, Faculty of Physics, Adam Mickiewicz University, Poznan, Poland), P. Michel (Côte d'Azur University, Côte d'Azur Observatory, CNRS, Lagrange Laboratory, Nice, Francia) to Paris, Paris, France), T. Santana-Ros (Departamento de Fı́sica, Universidad de Alicante, Alicante, Spain), P. Tanga (Université Côte d & # 39; Azur, Observatoire de la Côte d & # 39; Azur, CNRS, Laboratoire Lagrange, Nice, France), F. Vachier (Observatory Paris, Paris, France), A. Vigan (Aix Marseille Université, CNRS, Laboratoire d & # 39; Astrophysique de Marseille, Marseille, France), O. Witasse ( European Space Agency, ESTEC – Office h a scientific support, the Netherlands), B. Yang (European Observatory of the South, Santiago, Chile), M. Gillon (Space Science, Technology and Astrophysics Research Institute, University of Liège, Liège, Belgium), Z. Benkhaldoun (Ouikameden Observatory, High Energy Physics and Astrophysics Laboratory, Kadi Ayad University, Marrakech, Morocco), R. Szakats (Konkoli Observatory, Astronomy and Earth Sciences Research Center, Hungarian Academy of Sciences, Budapest, Hungary), R Hirshno (Institute) observatory, Faku Physics, Adam Mi University Tzkevich, Poznan, Poland), R. Duffard (Institute for Astrophysics of Andalusia, Glorieta de la Astronomy, Granada, Spain), A. Chapman (Buenos Aires, Argentina), J. L. Maestre (Observatory de Albox, Almeria, Spain)

ESO is the most important intergovernmental astronomical organization in Europe and the most productive terrestrial astronomical observatory in the world. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, together with the host country Chile and Australia as strategic partner. ESO is pursuing an ambitious program focused on the design, construction and operation of powerful ground-based monitoring facilities, enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organizing cooperation in astronomical research. ESO operates three unique world-class observation sites in Chile: La Silla, Paranal and Chajnantor. In Paranal, ESO operates the very large telescope and its world-leading very large interferometer telescope, as well as two mirror telescopes, VISTA operating in the infrared telescope and the VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov South Telescope, the largest and most sensitive gamma ray observatory in the world. ESO is also a major partner in two Chajnantor facilities, APEX and ALMA the largest existing astronomical project. And at Cerro Armazones, near Paranal, ESO is building a 39-meter-long, extremely large telescope, the ELT, which will become the "world's largest eye in the sky."


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