Experts in many fields are trying to describe how the ring around the dwarf planet Quaoar exists.
Recent telescope data has revealed that a small planet at the edge of our solar system is surrounded by a dense ring. And scientists struggle to explain why.
Simulation of a dwarf planet wandering the solar system.
Simulation of a dwarf planet wandering the solar system.
Celestial body Quaoar, Sometimes also considered a dwarf planetis one of approximately 3,000 objects orbiting the Sun beyond the orbit of Neptune and has a diameter of 1,110 km (7th largest on the list of dwarf planets, Pluto and Eris being the largest) . .
Observations of Quaoar made from 2018 to 2021 show that the dwarf planet has a ring further away from it than scientists previously imagined. This is according to a press release from the European Space Agency after using ground-based telescopes and a new space instrument called Cheops Telescope to collect data.
According to common sense, all the matter that makes up Quaoar’s dense belt should have condensed and formed a small moon. But it’s not like that.
The European Space Agency said: “Early results suggest that cold temperatures at Quaoar may play a role in preventing icy particles from sticking together, but further investigation is needed.”
Exceeding Roche limits
Before these new Quaoar observations, most scientists thought that planets could not form rings beyond a certain distance. This is a widely accepted mechanical rule applied to celestial bodies that states that material orbiting a planet will form a spherical body (or we call it a moon) if it orbits at a certain distance, far enough from the planet. But this moon would be torn apart if it came close to what we call “Rock Limit”, a point at which the planet’s tidal forces will be stronger than the gravitational force holding the moon together.
Quaoar orbits between Neptune and Pluto.
Quaoar’s orbit is between Neptune and Pluto.
For example, all of the rings around Saturn lie within the planet’s Roche limit. What’s curious about Quaoar, however, is that its rings lie beyond the Roche limit, in the region where matter would have formed the moon.
Giovanni Bruno of the INAF Astrophysical Observatory in Catania, Italy, said: “Based on our observations, the classical notion that dense rings exist only within the Roche limit of a celestial body needs to be radically revised.”
How to study a dwarf planet from a distance?
According to the ESA, the collection of data revealing the strange belt of Quaoar is already a reason to celebrate. Due to the planet’s small size and distance from Earth, researchers wanted to observe it using using the occultation (occultation) method. In this method, people observe a planet while waiting for it to be backlit by a star with sufficient apparent brightness.
According to the ESA, this can be an extremely difficult process because the telescope, planet and star must all align perfectly. This observation was made possible thanks to the space agency’s recent efforts to provide an unprecedented detailed map of the stars.
ESA also used the Cheops telescope, launched in 2019. Cheops often studies exoplanets or celestial bodies outside our solar system. But in this case, he’s aiming for the closest target, Quaoar. Although it is within the Solar System, the orbit around the center of the Sun is further than that of Neptune, which has an orbit of about 44 AU (1 AU is the average distance between Earth and the Sun).
Isabelle Pagano, director of the INAF Catania Astrophysical Observatory, said: “At first I was a little skeptical about the possibility of doing this with the Cheops glasses. But it worked.” And according to the ESA, the Cheops observation marks the first time that one of the most distant planets in our solar system has been observed with a space telescope.
The researchers then compared the data collected by Cheops with telescope observations on Earth, leading to their surprising discovery.
Bruno Morgado, a professor at the Federal University of Rio de Janeiro in Brazil, who led the analysis, said: “When we put everything together, we saw a decrease in brightness that was not caused by Quaoar, but indicated the presence of matter in a circular orbit around it. We know we see one belt around Quaoar“.
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Quaoar was discovered by astronomer Chad Trujillo on June 5, 2002., as he identified it in images obtained the previous night from the Palomar Observatory’s Samuel Oschin telescope. This discovery was submitted to the Minor Planet Center on June 6, and Trujillo and his colleague Michael Brown were credited for this discovery. At the time of its discovery, Quaoar was located in the constellation Ophiuchus, with an apparent magnitude of 18.5. Its discovery was officially announced at a meeting of the American Astronomical Society on October 7. 2002. Quaoar orbits approximately 43.7 astronomical units (6.54 × 109 km; 4.06 × 109 mi) from the Sun with an orbital period of 288.8 years. Quaoar has a low orbital eccentricity of 0.0394, meaning its orbit is almost circular. Its orbit is moderately inclined to the ecliptic by about 8 degrees, typical for the population of small classical Kuiper Belt Objects (KBOs) but exceptional among large KBOs. Quaoar is not significantly perturbed by Neptune unlike Pluto, which is in 2:3 orbital resonance with Neptune (Pluto orbits the Sun twice for every three orbits made by Neptune). Quaoar is the largest body classified as a cubewano, or classical Kuiper Belt object, by both the Minor Planet Center and the Deep Ecliptic survey (although the larger dwarf planet Makemake is also classified like a block). Quaoar sometimes comes closer to the Sun than Pluto, because the aphorism of Pluto (the greatest distance from the Sun) lies beyond and below the orbit of Quaoar. In 2008, Quaoar was only 14 AU from Pluto, making it the closest large object to Pluto in 2019. The rotation period of Quaoar is uncertain and two possible rotation periods for Quaoar are given (8 .64 hours or 17.68 hours). Derived from Quaoar’s rotational light curves observed from March to June 2003, its rotation period was measured at 17.6788 hours. Quaoar’s albedo or reflectivity may be as low as 0.1, which is still much higher than the lower estimate of 0.04 for 20,000 Varuna. This could indicate that fresh ice has disappeared from Quaoar’s surface. The surface is moderately red, meaning that Quaoar is relatively more reflective in the red and near-infrared spectrum than in the blue. The Kuiper belt objects Varuna and Ixion are also moderately red in their spectral layer. Larger Kuiper Belt objects are often much brighter because they are covered in cooler ice and have a higher albedo, and are therefore neutral in color. A 2006 model of internal heating by radioactive decay suggests that, unlike 90482 Orcus, Quaoar may not be able to maintain an internal water ocean at the edge of the mantle core. |
Article source: 1thegioi
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Experts in many fields are trying to describe how the ring around the dwarf planet Quaoar exists.
