He liked to make the planets watch, and he wanted no better joy
Than Simply Seeing Telescopes Pointed At It From Earth: “A Naughty Little Comet”, Ella Wheeler Wilcox
There are certain small playfully frolicking objects in our Sun’s family that stubbornly refuse to be easily categorized. Main Belt Comets (MBC) are such objects! They are a newly recognized group, circling our Solar System within the handheld asteroid beltIt lies between the orbits of Mars and Jupiter. MBC they are strange and puzzling little worlds that exhibit both the physical characteristics of comets and the orbital characteristics of asteroids. Because they possess characteristics of two different groups of inhabitants of the Solar System, their origins have been somewhat difficult to determine. Some astronomers now suggest that members of this strange family are the shattered fragments of large main belt asteroids that were destroyed in catastrophic collisions with other asteroids.
Comets are small icy bodies that make a long and treacherous journey through the Solar System in long elliptical orbits. They are famous for their bright, fluttering tails that come out when they travel close enough to the Sun. This is because heat and solar winds combine to melt the surface of their icy cores.
Comets and asteroids are the remains of a myriad of rolling bodies that existed when our Solar System was very young. Our Solar System was born about 4.6 billion years ago with the collapse of a relatively small, dense pocket embedded within a gigantic, cold, dark molecular cloud. Most of the collapsed bag froze in the center and eventually caught fire due to nuclear fusion, giving birth to our star, the Sun. The remaining mass flattened out and became what is called a protoplanetary accretion disk from which the eight main planets, their many fascinating moons, comets, asteroids and other small objects in the Solar System formed.
Protoplanetary accretion disks Numerous stars inhabiting young star clusters have been observed circling. They develop at the same time as a baby star is born, but the early stages cannot be seen because they are veiled in an opaque envelope of dust and gas. Tea accretion disk feed material to hungry baby star, gold protostar, and it is both very hot and extremely massive. Thesis discs they can remain around their young stars for about 10 million years.
By the time the young star reaches what is called the Tauri stage, the nutritive disc has become thinner and much colder. HAS Tauri star is a very young baby bouncing off an energetic variable star that is less than 10 million years old. Such stars have a mass similar to, or perhaps slightly less than, our Sun, which is a relatively small star. Tauri stars have diameters several times that of our Sun, but are still in the process of shrinking. Baby Sun-like stars shrink as they age. By the time the young star has reached this stage, less volatile materials have begun to condense near the center of the star. accretion disk, forming very, very sticky dust grains that are so fine they look like smoke, instead of the household dust that needs to be swept up. These very fine, sticky, smoke-like powder grains contain crystalline silicates.
Very fine particles of smoke-like dust coalesce to form larger and larger objects within the dense disk environment in which they live. The tiny dust grains form objects up to several centimeters in size, and these aggregate even more to give rise to planetesimals. planetesimals they are the building blocks of planets, and can reach sizes of 1 kilometer across or more. planetesimals They are very abundant and spread all over the world. protoplanetary accretion disk–and some survive long enough to remain as relics billions of years after the formation of the mature planetary system. asteroidslike those that inhabit the Solar System itself, are rocky remains planetesimals. kitesinstead they are relic here planetesimals from the outer limits of our Solar System. Tea asteroids they are the remaining building blocks of the rocky inner planets: Mercury, Venus, our Earth, and Mars. Tea comes from they are the leftover building blocks of the outer giant planets of gas and ice: Jupiter, Saturn, Uranus and Neptune.
Tea asteroids are found mainly in the handheld asteroid beltalthough there are several different populations of these rocky objects that reside outside of this Beltalso. kites they are fragile and ephemeral bodies, sometimes dismissively called “dirty snowballs” or “icy balls of mud”, depending on the observer’s point of view. They are strangers, beautiful travelers from afar.
The here, dirty comes from it plunges into Earth’s warm inner region of the Solar System from two dark, frozen domains at the outer limits. The first is called the Kuiper belt. Tea Kuiper belt revolves around our star beyond the orbit of Neptune, the furthest of the eight major planets from the Sun. The second domain of comets is the oort cloudwhich is a huge sphere of icy objects believed to encircle our entire Solar System.
every time a bum come makes its perilous journey into the interior of the Solar System, loses some of its mass through sublimation of its surface ices and gas: the icy surface of the core turns to gas and creates a cloud called eat. Solar radiation pushes dust particles away from the eatand this forms the famous dusty flickering tails of come.
rocky, metallic asteroids in it main belt do not normally exhibit this type of come-Similar behavior. asteroids in it main belt they are not supposed to develop eat or flickering, fluttering tails. However, the recently recognized class of Main Belt Comets they exhibit precisely this type of behavior, as they orbit the Sun in a manner that is characteristic of asteroids–not come!
naughty little kites
MBC they are extremely puzzling. They look like kites with their tails and eatbut they rotate in orbits inside that of the planet Jupiter, like asteroids!
The first of this puzzling group to be discovered was the asteroid 1979OW7, which was rediscovered and renamed 1996 N2and later designated a comet by Dr. Erik Elst and Dr. Guido Pizarro in 1996. It now wears a cometary designation as 133P/Elst-Pizarro. For many years, determining the nature of this enigmatic little object was a problem. It was originally meant to be the tragic result of a collision between two asteroids. However, 133P sublimated and developed a tail like a come in three successive perihelion passages, and this clouded the matter. Tea perihelion of an object refers to that point in its orbit when it is closest to the Sun–its aphelion that’s when it’s further away. This behavior, at the time, indicated to puzzled astronomers that the asteroid impact model was unlikely.
Some of the currently known MBC, in addition to 133Pis it so 176P/LINEAR, 238P/Read, P2008 R1 (Garradd), P/2010 R2 (The Holy), P/2010 A2 (LINEAR), 596 Scheila, 300163, Y P/2012 F5 (Gibbs). Some astronomers now suggest that these objects are, in fact, the remains of larger bodies torn apart in recent collisions, and that they inherited ice from their parent asteroid, causing them to exhibit comeHowever, to add credibility to this theory, it was necessary to first determine if the MBC are members of a distinct family of asteroids: groups of asteroids that have similar orbital characteristics, such as orbital inclination Y eccentricity. All members of a particular asteroid family are believed to be broken off pieces of a larger asteroid that was pulverized in a collision.
Serbian astronomer Dr. Bojan Novakovic, from the Department of Astronomy at the University of Belgrade, is currently investigating the mysterious origins of MBC, together with colleagues Dr. Henry Hsieh and Dr. Alberto Cellino. The team of astronomers focused on one prime example: the P/2006 VW 139 WBCand his goal was to see if it could be assigned to a family of asteroids. P/2006 VW 139 It was originally classified as an asteroid, but was eventually reclassified as a WBC in 2011, when astronomers in Hawaii discovered that it had a tail.
Dr. Novakovic began his study at the astdys Database, which is a catalog of 398,841 asteroids. There are less than a dozen verified examples of MBC, so finding other members of this family of asteroids among millions upon thousands of potential candidates was not exactly an easy job. The team of astronomers used what is called the hierarchical grouping method and the cut distance parameter to work your way through the candidates. They successfully narrowed the possibilities down to just 24 asteroids. The next step was to determine the orbital characteristics that these 24 asteroids possess. For this task, Dr. Novakovic used a mathematical model called backward Integration, “which can be used to distinguish real family members from intruders,” he commented in the November 7, 2012 International Scientific Grid This Week (isgtw).
To investigate the orbital characteristics of the candidate family members, Dr. Novakovic needed to analyze a large number of calculations that were “computationally expensive and would take months to perform on a typical PC,” he added. Finally, Dr. Novakovic and his colleagues were able to reduce the P/2006 VW139 family up to only 11 members.
The most valuable conclusion of Dr. Novakovic’s study, which was published in the Monthly Notices of the Royal Astronomical Society, is that P/2006 VW139 and its 11 siblings are part of a young family of asteroids that probably came into being around 7.5 million years ago. “[Asteroid] Families are considered young if they are less than 10 million years old,” Dr. Novakovic continued. This indicates that around 7.5 million years ago, a large asteroid smashed into another asteroid and broke up into 11 smaller fragments. :P/2006 VW139 and her 10 sisters.
P/2006 VW139 became a WBC because it inherited the deeply buried ice belonging to its catastrophically pulverized parent asteroid. This ice eventually vaporized, producing a fluttering tail that is characteristic of comets. “The fact that ice still exists near the surface of P/2006 VW 139 means that its surface is relatively young,” Dr. Novakovic noted in the November 7, 2012 esgtw. This means that P/2006 VW 139 and his 10 sisters were born long after the Main Asteroid Belt.
This finding is important because it supports the theory that MBC are born in asteroid collisions within the handheld asteroid beltand not through other means.
