Comet Lulin is here! Go see it now!

Some of you may have already heard of Comet Lulin. And some of you may even have seen it or photographed it. I know I’m late to mention this comet, but it’s better late than never, right? :-)

Comet Lulin was discovered in July 2007. The comet was on the images taken by Taiwanese astronomer Lin Chi Sheng (hey, I have personally talked to this guy before when he visited Malaysia in year 2000; but I don’t think he remember me…) at the Lulin Observatory in Taiwan but it was Quanzhi Ye from China who first discovered a moving object from these images.

At first it was thought to be an asteroid, but later was confirmed to be a comet. The comet was named Comet Lulin (C/2007 N3), after the observatory where the images were taken. This discovery was actually part of the Lulin Sky Survey Project to explore the various populations of small bodies in the solar system, especially objects that possibly could pose a hazard to the Earth.

Comet Lulin had swing by the Sun and is now heading our way. Don’t worry, it’ll not hit us; at its closest distance, on this Feb 24, it’ll still be 61 million km away, about 160 times the Earth-Moon distance.

This comet is moving fast in our sky due to its unusual orbit. Lulin is actually moving in the opposite direction as the planets, therefore from our perspective, it’s moving quickly against the background stars and these changes can be easily observed from night to night.

This westward movement of Lulin makes it visible earlier and earlier everyday. Currently it rises around midnight. Over the next few weeks, it will rise averagely 20 minutes earlier each night.

It is currently at magnitude 5 or 6, easily visible in binoculars, and can be detected with the naked eye under a dark sky. It is predicted to brighten up to 4th or 5th magnitude, but we can never know for sure, especially for comet on its maiden trip around the Sun. We may have surprises… or disappointment…

These few days are not a good time for observation because the bright Moon is in the way.

Click here for the location of Comet Lulin from Feb 13 to Mar 2, 2009.

Lulin has just left the constellation Libra and now heading into Virgo. On Feb 16, it’ll pass very close to the brightest star in Virgo – Spica, just 3 degrees north of it. A binocular view will show the bright star and the comet in the same field of view. Spica rises around 11 pm on Feb 16.

The comet will then continue its fast and furious journey across Virgo. By Feb 23, it leaves Virgo and moves into Leo to meet up with Saturn on Feb 24. Feb 24 is also the date for closest approach. Saturn can be easily visible to the naked eye at the lion’s hind legs, and hopefully Lulin could be as well. The comet is almost at opposition now, and can be seen in the east as the Sun sets.

If you observe the chart, you’ll see that the gaps (distance) between the days are getting larger and larger. Around Feb 24, Comet Lulin will be racing at more than 5 degrees per day, and will be leaving Leo in about a week’s time. This speedy motion is fast enough to show obvious motion when observes through telescope.

As the comet moves away from the Sun and Earth after Feb 24, it fades quickly. Four days later on Feb 27, it’ll pass by within 1 degree south of Regulus – the brightest star in Leo. On Mar 5, Lulin can be seen near to M44, the Beehive Cluster, and probably not visible to the naked eyes.

Pictures of Comet Lulin show its greenish coma and two tails. The green colour comes from cyanogen (CN) and diatomic carbon (C2). Both of these substances glow green when illuminated by sunlight in the near-vacuum of space.

The two tails – a normal tail and an anti tail – are the dust tail and ion tail. Ion tail is ionised gas pushed away from the comet by the solar wind, so it always point directly away from the Sun.

The dust tail, as its name implies, are a trail of dust left behind by the comet along its orbit as it moves through the solar system. Dust tends to traces the comet’s orbit, since it is heavier and thus harder to push around by the solar wind. Because of this, dust tail does not point directly away from the Sun.

For Comet Lulin, it is leaving the Sun behind. The solar wind pushes on the ionised gas from “behind” and thus creating an ion tail “in front” of the comet – an anti tail. The comet dust, however, stay where it was drop, thus forming a dust tail trailing behind the comet.

Advertisements

~ by thChieh on February 12, 2009.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

 
%d bloggers like this: