Surely the discovery of Comet ISON in September 2013 came as an exciting surprise at least in the scientific world. However Comet ISON is expected to be the most spectacular among several other comets and asteroids to come within the inner solar system and potentially close to our planet, the Earth.
It may seem like a well-orchestrated campaign. The fact is that 2013 proved to be the year of the comet and that simultaneously the Rosetta mission is preparing to turn its tools and land on a comet nucleus. Is it just a coincidence? If it is, it is one of those coincidences that cheer the lives of scholars and lovers of astronomy. However the coincidence doesn’t stop there. Comet ISON has a path full of religious symbols and is expected to be the most spectacular too. Is it pure coincidence or something else related to faith?
So far there are three protagonists in 2013 with the tail of order, and all likely to be visible to the naked eye even from our skies. The first of these is scheduled for mid-March, is called Pan-STARRS , also known as the Easter Comet and as of today it has already begun to be photographed and collecting fans among astronomers and amateur astronomers in the Southern Hemisphere.
The comet Pan-STARRS , which makes a fine show in this photo made Feb. 16 by Ignacio Diaz Bobillo, in Argentina, is the big news of the southern sky these days. As demonstrated in recent weeks Pan-STARRS began to be followed and photographed. The observations culminate around March 10, when the comet will pass at a minimum distance from Earth of about 45 million km.
In reality it is difficult to estimate precisely the exact day when the comet becomes visible in our country and its maximum brightness. The forecasts are cloaked in an aura of uncertainty, as is always the case for comets, astronomical objects able to appear suddenly and disprove the calculations even on very short timescales. To make matters worse, the fact that this comet has not been already observed in a previous visit to the Solar System. Pan-STARRS is in fact a long-period comet (also referred to as aperiodic), which completes its orbit around the sun in about 110,000 years. For these reasons, when astronomers can only estimate when and how much will become bright in our skies. And if it is currently visible with a simple pair of binoculars for amateur astronomers Australians, many are willing to bet that in mid-March will become visible to the naked eye from Italian skies (see this link for the section on comets UAI Italian Amateur Astronomers Union ).
As its name indicates, Pan-STARRS or better C/2011 L4 Pan-STARRS was discovered June 6, 2011 by the telescope Panoramic Survey Telescope & Rapid Response System in Hawaii.At the time of its discovery, was about 1.2 billion miles from Earth and the first observations made it possible to calculate preliminary orbit, then improved in the following months. Pan-STARRS is from the Oort Cloud , a spherical cloud of icy bodies made ready to become comets that surrounds the solar system to the incredible distance from the Sun than 100,000 AU, or astronomical unit, that is 100,000 times the distance between the Sun and Earth, well beyond the orbit of Neptune, the last planet, located about 30 AU. Pan-STARRS has an orbit inclined at about 84 °, cutting the plane of the solar system, other carattrtistica typical for non-periodic comets.
But Pan-STARRS is only the first parade of the comet in 2013. The second oldest is the green Lemmon , already presented at the end of March and it promises to become visible in our own. With its long tail, unmistakable for the greenish color due to the gases that are evaporating from the nucleus, Lemmon has already been widely photographed in the southern hemisphere and one of the three wins (for now) the band more beautiful. Finally, the third protagonist of 2013 is already famous comet ISON , whose discovery was announced in September, and will close the year probably becoming the Christmas Comet of 2013. ISON, like her colleagues, promises great things: passing very close to the Sun, it will be incredibly bright, probably equaling the Moon, remaining visible even in daylight.