Its diameter is 1,300 kilometers* The diameter measurement was made possible thanks to the Hubble Space Telescope
The astronomers call the new body Quaoar "Quaoar" and pronounce it kwa-whar, at the time of one of their gods the Native American Indians worshipped. It lies a billion kilometers behind Pluto and it orbits the Sun once every 288 years in an almost perfect circle. Until recently it was just an interesting point of light. That's all astronomers have been able to see since it was discovered last June using ground-based telescopes, but now it's a respectable world in its own right.
Researchers using the Hubble Space Telescope measured Kva-Var and found it to be 1,300 kilometers wide - about 400 kilometers wider than the largest asteroid in the main asteroid belt - Ceres, and more than half the diameter of Pluto itself. In fact, it is the largest object discovered in the solar system since the discovery of Pluto 72 years ago.
Kuva-Var is larger in volume than all known asteroids combined and the researchers suspect that it is made of ice mixed with rocks, unlike the structure of comets. If so, the mass of Kava-Var is only one third of the mass of the entire asteroid belt.
Michael Brown and Chadwick Trujillo of the California Institute of Technology in Pasadena reported these findings yesterday (7/10) at the 34th meeting of the American Astronomical Society's Division of Planetary Sciences in Birmingham, Alabama.
Earlier this year, the pair used the 48-inch telescope at Plummer to discover Kava-Var as an 18.5-magnitude object in the summer constellation Ophiuchus. Although Kava-Var was relatively bright (by the standard of objects in this region) its disk was too small to be measured by the world's best ground-based telescopes.
Brown therefore requested observation time with the Hubble Space Telescope. Hubble's new camera system, which was installed only a few months ago, recognized that it is a ball with a diameter of 40 milliseconds, which represents at this distance a diameter of 1,300 kilometers. Only Hubble has the resolution necessary to detect the disk of such a distant world.
Like the planet Pluto, it wanders quava-var in the Kuiper belt, a field of glacial debris from comet-like bodies that extends 5 billion kilometers beyond Neptune's orbit. In the last decade, over 500 such icy bodies - Kuiper belt objects - or (KBO) were discovered. With a few exceptions most were significantly smaller than Pluto. The previous record holder was called Varona, and although it has not yet been given a name and is currently known as 2002 AW197, each of them was about 900 kilometers in diameter.
The name Kwa-Var (also known as 2002 LM60) has not yet been officially determined as it is a new discovery. The approval of the International Astronomical Union is necessary. Trujillo and Brown proposed the name to commemorate the creator god in the tradition of the Tonguba tribe who lived in the Los Angeles Valley, where Caltech is located. According to the legend, Kwa-Var descended from the sky, turned chaos into order and created humanity.
Eventually, Brown predicts, KBOs even larger than Mikva-Var will be found and Hubble will be valuable for following up with ground observations to identify the size of these bodies. In the meantime, Kva-Var holds the record - a kind of pharaoh at the expense of greater things to be discovered.
עודכן ב-08/10/02 22:18
The discovery of a new object strengthens the hypothesis that Pluto is not a planet
by Tamara Traubman
"Quor" is a new and frozen world; Its size is about half the size of Pluto: about 1,300 km
Astronomers who recently observed through telescopes the edges of the solar system, discovered a new object, the largest found since Pluto was discovered 72 years ago. The object is 1.6 billion kilometers from Pluto, the farthest planet from the Sun. The area where the new object is found is known as the "Kuiper belt", an area full of small, icy objects that remain as cosmic fossils from the early days of the solar system.
Some planetary experts believe that the discovery of the new bone is another piece of evidence undermining Pluto's status as a planet. According to many astronomers, Pluto is not a real planet but a Kuiper belt object that was captured by the Sun's gravity and began to circle around it.
The astronomers who discovered the object, Dr. Michael Brown and Dr. Chadwick Trujillo from the California Institute of Technology, USA, decided to call it "Quaoar". Quor is the god of the first Native Americans who settled in the Los Angeles Basin. According to Indian mythology, Kuvar "descended from the sky and after creating order out of chaos he placed the world on the backs of seven giants".
Brown and Trujillo first observed the quasar in June, using the telescope at the Palomar Observatory in San Diego. The object then appeared to them as a small, pale point of light. To get a clearer picture of him they aimed the more powerful lenses of the Hubble Space Telescope at him.
The observations taught that Kvar is a new and frozen world, made of ice and rocks, and that its diameter is about 1,300 kilometers. It is a very small object in relation to the planets - its size is about half the size of Pluto. "However, this is the largest object discovered in the Kuiper belt so far," says Ilan Manolis from the Israeli Astronomical Society, "but astronomers are convinced that there are icy worlds larger than it in the Kuiper, and it's only a matter of time until they discover them."
According to Manolis, there may even be objects larger than Pluto in the Kuiper belt. The difficulty in locating them is due to the fact that they are farther from Earth and darker than the planets. That's why the telescopes have difficulty detecting the faint light coming from them.
In a message published by NASA, it was stated that Kvar is expected to yield new insights into the "mysterious population of objects" located at the edge of the solar system. The first object in the distant Kuiper Belt region was discovered by Prof. David Jewitt of the University of Hawaii. In 1951, Prof. Gerard Kuefer, a Dutch-American astronomer after whom the region is named, hypothesized that other small bodies might be found there. Indeed, Manolis says, since then about 500 objects have been discovered there, and the accepted hypothesis today is that the Kuiper belt is the source of some of the comets.
Many astronomers speculate that the Kuiper belt is also the origin of Pluto. The diameter of Pluto, the smallest of the planets, is a total of 2,250 km and many believe that it should be classified as a Kuiper belt object. "The discovery of the quaver proves that there are relatively large objects in the Kuiper Belt and it is possible that Pluto is one of them," says Brown in an interview with the New York Times newspaper. According to him, "If Pluto were discovered today, no one would even consider calling it a planet, because it is clearly a Kuiper Belt object."
