2012年1月30日星期一

What may be the first comet of the Sekanina-Chodas

What may be the first comet of the Sekanina-Chodas "cluster" was discovered this past Nov. 27 by Terry Lovejoy, an amateur astronomer cheap moncler jackets, in Queensland. As soon as orbit calculations indicated that Lovejoy's comet was indeed a Kreutz sungrazer, excitement among astronomers became very high, as this was the first such comet to be discovered from the ground in over four decades. All the scientific instrumentation that is available now could be brought to bear on it.

Comet Lovejoy did not disappoint. As soon as it entered the field of view of the SOHO coronagraphs on Dec. 13, it immediately became clear that it was, by far, the brightest Kreutz sungrazer ever detected by SOHO. It brightened dramatically over the next two days as it approached the Sun, and in addition to observations with the instruments aboard SOHO several other sun-studying spacecraft were brought to bear on it, including both spacecraft of the Solar Terrestrial Relations Observatory (STEREO) mission, the recently launched Solar Dynamics Observatory (SDO) spacecraft, and the Japanese Hinode mission moncler outlet 2011.

Because Comet Lovejoy did not seem to be a large comet like Ikeya-Seki, most astronomers did not really expect it to survive its closest encounter with the sun, a passage of just 200,000 miles above the sun's "surface" early on December 16. But later that day it emerged from behind the sun still as a very brilliant object, although it had apparently shed its tail. As the hours went by and Comet Lovejoy receded from the sun, it began to grow a new tail, which soon was almost as bright and as long as its old one.

When Comet Lovejoy was bright and near the sun several astronomers attempted to view it during daytime, and although a couple of astronomers did report success, for the most part the comet remained elusive. It is now starting to re-emerge into the southern hemisphere's morning sky, and according to the handful of reports that have been made at this writing, the tail that has been seem emerging out of the bright dawn is bright and quite long.

We'll know more within a few days as the comet continues to climb out of the sunlight, but it's conceivable that our sky-watching friends in the southern hemisphere cheap moncler jackets for women could be in for quite a treat for the next week or so. Comet Lovejoy passes 46 million miles from Earth early next month and then close to the south celestial pole a couple of days later.

Meanwhile, those of us who are north of the equator are pretty much out of luck, although if it doesn't fade too quickly it might be bright enough to detect with moderate-sized backyard telescopes when it comes back north late in January.

Even though very few eyes have actually glimpsed it, Comet Lovejoy has undoubtedly been one of the most exciting comets that has come our way within the past several years. And, if it really is the first sungrazer of the "cluster" predicted by Sekanina and Chodas, we may have even cheap moncler jackets for men more representatives of this remarkable group of comets perhaps another brilliant comet like Ikeya-Seki to dazzle our skies during the years to come.

没有评论:

发表评论