An Amazing Spectacle is Coming

Great Comet Nevski-Novichonok 2013Credit: Javrsmith

Comet Nevski-Novichonok is on its way. This visitor from the depths of space is going to be spectacular. Throughout history, many comets have been stunning but few have been spectacular. Nevski-Novichonok is destined to be one of the best of all time. Discovered in September, 2012, it was researched and found to be on a very close trajectory to the sun. In fact, it will seem to come close enough to graze the solar atmosphere. This factor is what will make this comet very bright in the sky. It will likely even be visible in the daytime.

There is always a degree of uncertainty when evaluating the maximum brightness of a comet. They are often discovered when they are extremely far away when they appear to be insignificant, dim objects. By comparing two photographs, astronomers realize that some objects have moved compared to those that remain fixed in place. The identified object may be a comet, an asteroid or even a piece of space debris near the Earth. By calculating the path in space for the object, a precise determination of the object can be made. For some, the path is calculated which show it to be on an orbit of the sun, which defines it as a comet. These items are quite rare.

After a comet is identified, based on its orbit, the determination of the eventual brightness is attempted. Several factors affect the brightness value. Chief among these is the eventual proximity to the sun. The closest approach of the comet to the sun is called its "perihelion". Generally, the closer to the sun, the brighter the comet will be. Comet Nevski-Novichonok will have a perihelion of about 1 million miles. This is extremely close. The perihelion of Halley's Comet was 54 million miles. In 1986, that comet orbited the sun and was not very bright for Earthbound observers. In 1997, Comet Hale-Bopp passed the sun with over 84 million miles of separation. That comet was very much brighter and was a great object to observe for months. Considering that Comet Nevski-Novichonok is so very much closer to the sun at its perihelion, predictions are that the brightness of the 2013 will be extremely bright.

Other factors that influence comet brightness are the composition of the object and the size. Larger ones made predominantly of ice and dust are apt to be brighter. That is because they give off more of their material as they are warmed by the sun as they near perihelion. More rocky objects simply warm up without having as much material expelled. The ice and dust of a comet creates the distinctive tail, or coma, which is often visible from Earth. Each particle in the tail is illuminated by sunlight. More material in the tail provides more particles that can be lit. Comet tails can be millions of miles long, much of which is often visible from Earth.

Comet Nevski-Novichonok is likely to put on a show which might never be equalled. The comet passes within 0.012 astronomical units of the center of the sun. An "au" is almost 93 million miles and the sun's diameter is very large, so the comet will be about 680,000 miles above the surface of the sun. As mentioned, this close separation will cause the warm of the sun to heat up the ice and dust of the comet. The solar wind which emanates from the sun will buffet the comet and carry off particles. The solar wind will be very strong, and the comet well heated, as Comet Nevski-Novichonok nears perihelion. The particles will for a tail, or coma, beyond the comet. How long the tail will be is really anyone's guess. Many such tails are millions of miles long.

It is when this great comet nears the sun that things become interesting. How big will the comet's tail be? How illuminated will the particles be? Will the comet even survive the close approach. Other comets are called "sun grazers" because they pass even closer to the sun. Many of those don't survive the encounter. Perhaps Comet Nevski-Novichonok is large enough to escape unscathed. There is also the effect of Jupiter on the planet. As the object passes the giant planet, gravity is affected. This can affect the subsequent orbits of the comet. Currently, this 2013 comet takes perhaps a million years to orbit the sun. Jupiter may cause the orbit length, (or period), to increase or decrease. Jupiter may also deflect the orbit. This is an unlikely possibility but it has happened before. Comet Shoemaker-Levy 9 was so affected and it soon crashed into the giant planet. Comet Nevski-Novichonok is not likely to collide with a planet but its orbit may not be exactly stable after the 2013 close approach.

Luckily for those in the Northern Hemisphere, Comet Nevski-Novichonok will be high in the sky during the latter part of 2013. This is in marked contrast to Halley's Comet in 1986 which was very low for northern observers. Comet Hale-Bopp in 1996-97 was better positioned for northerners as well. Since it is never too early to prepare, those people in the Northern Hemisphere should acquaint themselves with the night sky in the fall and winter of 2012. Find out where north is for your location. Locate the North Star. This star is situated almost directly above the North Pole. As such, it makes a great locating point in the night sky. Stand outside at night where you have a clear view to the north. Look up at an angle  which corresponds to your current latitude. For the people in the USA, that will be between 25 and 49 degrees, 21.3 in Hawaii and 51-70 in Alaska. While the comet passes this start on January 8, 2014, it will be a better view in mid to late 2013 starting about when the comet passes through the Leo constellation. Look for a backwards question mark in the sky made up of about 7 stars. Find that and you'll be ready to view Comet Nevski-Novichonok.