Soho prepares for comet McNaught

Jan 12, 2007
Soho prepares for comet McNaught
Comet McNaught is plunging toward the Sun and brightening dramatically. The image was taken by Roger Johansen, Hammerfest, Norway, on 6 January 2007. Credits: Roger Johansen

Recently, sky watchers in the Northern Hemisphere have been enjoying the sight of Comet McNaught in the twilight sky. Now, solar physicists using the ESA-NASA SOHO spacecraft are getting ready for their view. For four days in January, the comet will pass through SOHO's line of sight and could be the brightest comet SOHO has ever seen.

As Comet McNaught heads towards its closest approach to the Sun on 12 January 2007, it will disappear from view for earthbound observers, becoming lost in the Sun's glare. That's where SOHO comes in. Poised in space between the Earth and Sun, SOHO ceaselessly watches the Sun and objects that pass nearby.

Comet McNaught will pass within a fifth of the distance between the Earth and the Sun. As the comet approaches the Sun, the amount of dust and gas it releases will increase dramatically, causing the comet to become extremely bright. "This might become the brightest comet SOHO has ever seen," says Bernhard Fleck, SOHO Project Scientist.

The material ejected from the comet forms the tails. There are two tails, the dust tail and the gas – or ion – tail. The dust tail is the brighter and is formed by the intense sunlight forcing dust particles away from the comet. The solar wind, a constant stream of material flowing from the Sun, drags ionized gas from the comet to create the ion-tail.

Researchers Karl Battams and Jeff Morrill at the Naval Research Laboratory in Washington, DC are planning colour filter observations of these two comet tails. "Close to the Sun the ion and dust tails move apart, a phenomenon that is often difficult to observe from the Earth. By measuring the ion-tail angle we can get information about the solar wind speed very close to the Sun," says Morrill.

Comet McNaught is moving through space on an inclined orbit. This will carry it above the Sun's north pole and across the Sun's equator, a place where there is a reversal of the magnetic properties of the solar wind. Crossing this boundary could cause the comet's ion-tail to fragment. Observations of such events are generally very rare, so SOHO's images of comet McNaught constitute an exciting opportunity for scientists.

After SOHO's work is finished, the comet will emerge from the Sun's glare and become visible again to earthbound sky watchers in the Southern Hemisphere. "It could become a really bright object in the twilight sky," says Fleck. The ghostly veils of a bright comet are amongst the most spectacular of sights that can be seen in the night sky.

Between 12 and 15 January, Comet McNaught will not be visible from Earth but everyone can still track the comet's passage near the Sun by looking at the SOHO images at soho.esac.esa.int/hotshots/ .

Source: ESA

Explore further: What's the brightest star in the sky, past and future?

add to favorites email to friend print save as pdf

Related Stories

Google hits back at rivals with futuristic HQ plan

5 hours ago

Google unveiled plans Friday for a new campus headquarters integrating wildlife and sweeping waterways, aiming to make a big statement in Silicon Valley—which is already seeing ambitious projects from Apple ...

Recommended for you

Could the Milky Way become a quasar?

Feb 27, 2015

A quasar is what you get when a supermassive black hole is actively feeding on material at the core of a galaxy. The region around the black hole gets really hot and blasts out radiation that we can see billions ...

Galactic dinosaurs not extinct

Feb 27, 2015

One of the biggest mysteries in galaxy evolution is the fate of the compact massive galaxies that roamed the early Universe.

Stars found forming at Milky Way's outer edge

Feb 27, 2015

Brazilian astronomers said Friday they had found two star clusters forming in a remote part of our Milky Way galaxy where such a thing was previously thought impossible.

New insight found in black hole collisions

Feb 26, 2015

New research by an astrophysicist at The University of Texas at Dallas provides revelations about the most energetic event in the universe—the merging of two spinning, orbiting black holes into a much larger ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.