Kenneth chanough In the mysterious and little-known periphery of the solar system, what is not seen is almost as telling astronomers as it is seen. All we have seen for decades is Pluto, which was discovered by astronomers Clyde Tombo in 1930. Netherlands, 1951- American astronomers kukuiper assume that other small objects will be found outside the orbit of Neptune. 8 billion miles from the sun, but not until 1992. David C. Jewitt and Dr. of the University of HawaiiJane X. Now at the University of Leiden in the Netherlands, Luu sees the first member now known as Kuiper Belt, a 300-mile- A wide object called 1992 qb1. One of the latest discoveries is 400-mile- A wide mini-planet in orbit near Pluto. It\'s too small to be a complete one. The mature planet, which is large enough, can re-discuss whether Pluto, the smallest planet, should also be considered a planet. More realistically, the mini-planet officially designated as 2000 EB173 will provide astronomers with a bright test object to study the composition of objects on the edge of the solar system. EB173 is the largest of the 70 known Pluto, which runs around the sun in a sloping oval path, similar to Pluto. Astronomers led by the doctor Dean of the Department of Physics at Yale, Dr. Charles baltai and Gustavo bruzur of the Venezuelan astronomical research center pointed out that, For a month, the inch telescope is on a sky every night, hoping to see the exploding stars and objects moving slowly in the night sky. In the spots of light, one--EB173 -- Slightly transferred from night to night. Astronomers watched images from advertisements in the early months and years, and found the same light spots in different locations, enabling them to calculate 243 of eb173-year orbit. The findings were released late last month at a meeting of the American Astronomical Society\'s Planetary Science Division in Pasadena, California. And has been submitted to the Journal of astrophysics. According to the amount of light reflected by EB173, Dr Baltay estimates it\'s 300 to 450 miles in diameter, possibly the second largest asteroid in the solar system after 567 kilometers. mile- The wide asteroid Valley star that runs between Mars and Jupiter. Some other objects in the koibel belt may be about the size of EB173, but because they have orbits farther than Pluto and Pluto, they reflect less sunlight and are Astronomical on Earth. For astronomers, the brightness of EB173 should make it easier for them to perform different types of observations. \"You can check the object more accurately than any other koibel belt object,\" the doctor said . \"Bradley E. Schaefer is a researcher at the University of Texas at Austin and a team member who found eb173. Interestingly, the first attempt to analyze the light reflected by EB173 did not have any results. If frozen water or methane is present on the surface, these molecules should absorb light of a certain wavelength- Identify unique color fingerprints that exist for different types of molecules. \"But these are not seen in this matter,\" said the doctor. His team observed at the Keke Observatory in Hawaii. This is a spectrum with no features at all. Astronomers have observed evidence of the ice on some other koibel-belt objects. Others have the same characteristic spectrum as eb173. Some scientists believe that characteristic-free spectra may indicate a surface of complex carbon. Through billions of years of cosmic ray bombardment, methane is transformed into a base molecule. \"Basically, it\'s like charcoal, burned wood . \"Jewitt said. \"In the range we can observe, it has no spectral features. \"Please click on the box to verify that you are not a robot. The email address is invalid. Please re-enter. You must select the newsletter you want to subscribe. View all New York Times newsletters. In the last five yearsStephen C. Professor of Physics and Astronomy, University of Northern ArizonaWilliam J. Roman Xin, professor of physics and astronomy at the University of Oklahoma, has been making a simpler observation of the koibel-belt objects, observing their overall hue. In 1998, they reported that there were two different colors for these objects: gray and red. How the solar system produces two different types of materials on the edge of the cold is a mystery. \"It doesn\'t match our theory of how the solar system is formed and evolved,\" Dr. Tegler said. \"You\'re looking at a similar temperature and what can be done there should be about the same. You can see how it becomes a problem to have two different surface properties. \'\'In the Oct. 26 issues of natureTegler and Dr. Follow-up to the Romanishin report Observations of additional koibel-belt objects. The division between the gray and red objects still exists, but they also find a new strange pattern: All the koibel objects with more than 3. It is red 7 billion miles from the sun. Strangely, the independent observation of the Doctor The group of Jewitt does not show Gray- The red split, but the uniform distribution of colors between the two shades. If the two groups observe the same object, they agree on the color. \"This may be some kind of pathology in their sample,\" said the doctor. Jewitt said. \"We are all a little confused and it is necessary that we all accept more data. \"Another mystery also deepens with additional observation. The solar system also seems to end abruptly not far from the outer limits of the Pluto orbit. In 1998 and 1999 days, astronomers at the University of Michigan and the University of Arizona searched for six skies, each of which was about the same size as the full moon. They found 24 new koibel objects but were not found 5 billion miles away. Their observations should be sensitive enough to detect 100mile- A wide object 6 billion miles away. The findings, also presented at the recent Planetary Science Conference, may indicate that more distant objects are too small to be seen, or at some point in the past, the gravity of a passing star may tear the outside of the solar system. Astronomers are still staring only at a part of the sky, and many expect to find a larger koibel belt object than eb173. If the result is as big as 1,400mile- Is wide Pluto, The Tenth Planet, or does astronomers think Pluto is just another rock in the koiber belt? \"Pluto is the biggest Pluto if you ask me,\" said the doctor. Brian G. Marsden, director, asteroid Center, International Astronomical Federation, Harvard University Located in Cambridge, Massachusetts, the Smithsonian Center for Astrophysics. A year and a half ago, doctor. Marsden was in astronomical controversy when he proposed to list Pluto as the first class. 10,000 registration of \"asteroids. \'\' Dr. Marsden saw the first. 10,000 is designated the honor of Pluto. Others think this is a downgrade, although Dr. Marsden did not propose to deprive Pluto of its status as the ninth planet, which was withdrawn in the subsequent uproar. \"My point is that Pluto should have a dual identity . \"Marsden said. \"It\'s obviously a chaebol. It can also be a planet. \"We are constantly improving the quality of text archives. Please send feedback, error reports, and suggestions to archid_feedback @ nytimes. com. A version of this article was published on the national F00004 page of November 7, 2000, titled: studying the composition of mini planets other than Pluto.