University of Alicante scientist helps discover ring around dwarf planet Haumea
UA senior lecturer Adriano Campo Bagatin has been part of the Institute of Astrophysics of Andalusia team who made the find published in Nature
Alicante. 17 October 2017
Latest issue of Journal Nature has echoed the results of the work carried out by the team led by José Luis Ortiz, from the Institute of Astrophysics of Andalusia (IAA), on stellar occultations by objects from the Solar System where University of Alicante senior lecturer Adriano Campo Bagatin, from the Department of Physics, Systems Engineering and Signal Theory and the UA Polytechnic School Institute of Physics Applied to Science and Technology participates.
The work done by researchers has revealed the presence of a ring around the dwarf planet Haumea, the most unknown star of the four dwarf planets found in the confines of the Solar System, beyond the orbit of Neptune, in a belt of objects made up of ice and rocks among which four dwarf planets stand out: Pluto, Eris, Makemake and Haumea.
Trans-neptunian objects are very difficult to study because of their low brightness and the enormous distances that separate us from them. A very effective though complex method is to study stellar occultations, which consist of observing the passage of these objects in front of the background stars (a kind of small eclipse). The method allows us to determine its main physical characteristics (size, shape, density) and has also been used with the dwarf planets Eris and Makemake with excellent results.
"We predicted that Haumea would pass in front of a star on 21 January 2017, and twelve telescopes from ten European observatories analysed phenomenon - as stated by Jose Luis Ortiz, the researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) that leads the research. Thanks to this deployment of media, we have been able to very accurately redefine the shape and size of the dwarf planet Haumea, with the surprising result that it is quite larger and less reflective than previously thought. It is also much less dense than previously believed and this solves some unknowns that were pending for this object."
Haumea is a unique object that revolves around the Sun in an elliptical orbit that takes 248 years to complete (at present it is about fifty times the distance between the Earth and the Sun from us), and its rotation speed is 3.9 hours, much faster than any other body further than a hundred kilometres across the Solar System. This speed caused Haumea to have an ellipsoidal form in its origin similar to a rugby ball. Thanks to the newly published data, it is known that Haumea measures about 2,320 kilometres on its longest side, almost the same as Pluto, but lacks a global atmosphere similar to that of Pluto.
FIRST TRANS-NEPTUNIAN OBJECT WITH A RING
"One of the most interesting and unexpected finds has been the discovery of a ring around Haumea. Until just a few years ago we only knew the existence of rings around the giant planets. Then, recently, our team also discovered that two small bodies located between Jupiter and Neptune, belonging to a group of objects called centaurs, have dense rings, which was a great surprise. We have just discovered that even more distant bodies than the larger Centaurs, with very different general characteristics, may also have rings,” as reported by Pablo Santos-Sanz, also a member of the IAA-CSIC team.
According to data obtained from occultation, the ring is located in the equatorial plane of the dwarf planet, as it is its larger satellite, Hi'iaka, and shows a 3: 1 resonance with respect to the rotation of Haumea, which means that the frozen particles making up the ring complete a rotation around the planet within the same time in which it rotates three times.
"There are several possible explanations for the formation of the ring; it could have been originated, for instance, after a collision with another object, or the release of some of the surface material due to the rapid rotation of Haumea,” Ortiz from IAA-CSIC said. It is the first finding of a ring around a trans-neptunian object, and shows that the presence of rings could be much more common than was believed, both in our Solar System and in other planetary systems.
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