Why is Comet ISON Green?…. and other updates
Great news, everyone! Astronomers world wide have confirmed that in the last day or so, ISON has increased in brightness to the point where it is visible to the naked eye. You still have to look closely, as it is still on the border of visibility. Astronomers expect the comet to brighten as it continues to approach the Sun, but no one can know for sure. Through telescopes the green color of the comet is visible.
So why is the comet green? It isn’t uncommon for comets to glow green. This is due to the presence of certain chemicals inside the comet that are released as the nucleus sublimates away into space. Most often these chemicals are cyanogen (CN) and diatomic carbon (C2). Both of these chemicals emit greenish-blue light when in a vacuum (like outer space) and exposed to large amounts of energy (which they are getting from the Sun).
Today I came across this awesome interactive website that allows you to track ISON (as well as other Solar System objects) through the sky from different points of view. I’ll be using it to see where ISON will be over the next view weeks, it also gives you key dates and info. Click the picture below to visit the site:
Unfortunately for us here in Baton Rouge, the next few days have a lot of clouds in the forecast! There will still be time to view the comet early next week once the sky clears… Between now and November 28 the comet is approaching the Sun. From Earth it will be getting closer and closer to the horizon in the early morning sky. If you can, try and view it before Thanksgiving. All you have to do is:
1. Wake up very early, around 5:00 AM!
2. Find a place with a clear view of the eastern horizon.
3. Find the constellation Virgo (outlined in the image above), it will be nearly due east.
4. Look for a faint fuzzy object
5. If you’re feeling up to it, bring the camera out and snap a picture. Click here for a past article about astrophotography tips, it is for a meteor shower, but similar rules apply.
6. While you’re out, don’t miss Saturn, Mercury, and Mars.
Astronomers are unsure of ISON’s fate after it’s close approach to the Sun (which will occur on Thanksgiving Day), it is possible that the Sun’s gravity will cause ISON’s nucleus to break apart. If ISON survives its close encounter with the Sun, it will be visible once again in the morning sky around December 6th. Cross your fingers for ISON’s safe passage around the Sun, and happy viewing!
Comet ISON Suddenly Brightens as it Dives Toward the Sun (universetoday.com)