Comet Lovejoy's wiggle offers glimpse of Sun's variable coronal magnetism (w/ video)

Jun 07, 2013 by Bob Yirka report
Visualization of the coronal magnetic field through which comet Lovejoy passed. The magenta arc indicates Lovejoy's path, which traversed both open (orange) and closed (blue) magnetic field lines. The unexpected directions and changes in tail motion were found to be consistent with the orientation and variation of the magnetic field along this path, which was determined from a sophisticated computer model of the solar corona. Credit: Cooper Downs

(Phys.org) —A team of researchers studying comet Lovejoy has discovered that as the ball of ice passed through the sun's corona in December 2011, its tail wiggled in a way that allowed them to better understand coronal magnetism. In their paper published in the journal Science, the team says observations of Lovejoy's close call with the sun have helped them improve models used to describe the irregular nature of coronal magnetism.

is part of a class of comet's known as Kreutz sungrazers—they are believed to be remnants of a much larger comet that broke apart hundreds of years ago. They're called sungrazers because they have a tendency to strike the sun's corona at an angle. Most break apart and disappear—Lovejoy did not. Instead it spun around the sun at very and shot back out into space, only to break apart several days later. Sungrazers offer researchers a unique way to study the sun's corona—it's too hot to send a probe—temperatures typically hover in the millions of degrees. Instead they can watch what happens to comets as they are impacted by intense temperatures and magnetism.

This video is not supported by your browser at this time.

This video is not supported by your browser at this time.

What the researchers found most interesting about Lovejoy's close call was the movement of its tail as it passed though parts of the corona—it wiggled, displaying major changes in intensity, direction, persistence and magnitude. Suspecting the wiggling was due to interactions between the ions that make up the comet's tail and magnetism from the corona, the researchers sought to reproduce the effect using models—one of which gave a close approximation of the real thing, suggesting a high degree of accuracy.

Multi-wavelength emission from the portion of the solar corona traversed by comet Lovejoy (magenta arc). Each color represents a different wavelength of extreme ultraviolet (EUV) light. The unique temperature sensitivity of each spectral window provides complementary information into the distribution of hot plasma in the solar corona, which is typically around one to three million degrees. The top row shows NASA Solar Dynamics Observatory (SDO) images. These are compared to emission generated from a computer model of the corona in the bottom row. This comparison was used to understand how well the model describes the large-scale plasma structure of the corona during this time period. Credit: Cooper Downs

Gaining a better understanding of coronal magnetism has become more critical as Earth-bound technology has become more sophisticated. and storms can disrupt and other and in some cases the grid itself.

Comet Lovejoy came within 140,000 kilometers of the surface of the sun—its path was traced using ultraviolet light based equipment at facilities such as the Solar Terrestrial Relations Observatory and the Solar Dynamics Observatory. The researchers are hoping that their models will one day be able to help with space weather forecasting, giving operators of sensitive equipment time to shut down before it's too late.

Explore further: Astronauts to get 'ISSpresso' coffee machine

More information: Probing the Solar Magnetic Field with a Sun-Grazing Comet, Science 7 June 2013: Vol. 340 no. 6137 pp. 1196-1199
DOI: 10.1126/science.1236550

ABSTRACT
On 15 and 16 December 2011, Sun-grazing comet C/2011 W3 (Lovejoy) passed deep within the solar corona, effectively probing a region that has never been visited by spacecraft. Imaged from multiple perspectives, extreme ultraviolet observations of Lovejoy's tail showed substantial changes in direction, intensity, magnitude, and persistence. To understand this unique signature, we combined a state-of-the-art magnetohydrodynamic model of the solar corona and a model for the motion of emitting cometary tail ions in an embedded plasma. The observed tail motions reveal the inhomogeneous magnetic field of the solar corona. We show how these motions constrain field and plasma properties along the trajectory, and how they can be used to meaningfully distinguish between two classes of magnetic field models.

Related Stories

Heliophysics nugget: Sungrazing comets as solar probes

Dec 06, 2012

(Phys.org)—Heliophysics nuggets are a collection of early science results, new research techniques and instrument updates that further our attempt to understand the sun and the dynamic space weather system that surrounds ...

Using many instruments to track a comet

Dec 13, 2011

(PhysOrg.com) -- In 16 years of data observations, the Solar Heliophysics Observatory (SOHO) -- a joint European Space Agency and NASA mission –- made an unexpected claim for fame: the sighting of new comets at an alarming ...

Christmas comet Lovejoy captured at Paranal Observatory

Dec 24, 2011

(PhysOrg.com) -- The recently discovered Comet Lovejoy has been captured in stunning photos and time-lapse video taken from ESO’s Paranal Observatory in Chile. The comet graced the southern sky after ...

How did comet Lovejoy survive its trip around the sun?

Mar 14, 2012

It was just about three months ago that the astronomy world watched in awe as the recently-discovered comet Lovejoy plummeted toward the Sun on what what expected to be its final voyage, only to reappear on ...

Recommended for you

Astronauts to get 'ISSpresso' coffee machine

7 hours ago

Ristretto or lungo? Not a question astronauts on the International Space Station normally have to contemplate, but that is about to change thanks to a new zero-gravity coffee machine being delivered this weekend.

What is the difference between asteroids and comets?

11 hours ago

Asteroids and comets have a few things in common. They are both celestial bodies orbiting our Sun, and they both can have unusual orbits, sometimes straying close to Earth or the other planets. They are both ...

Second time through, Mars rover examines chosen rocks

14 hours ago

(Phys.org) —NASA's Curiosity Mars rover has completed a reconnaissance "walkabout" of the first outcrop it reached at the base of the mission's destination mountain and has begun a second pass examining ...

User comments : 6

Adjust slider to filter visible comments by rank

Display comments: newest first

AryaPutraSRJ
5 / 5 (3) Jun 07, 2013
We are so good at understanding things indirectly , Wonderfull research on sun :)
Lischyn
1 / 5 (2) Jun 07, 2013
If this thing can get through, can we not copy a spacecraft like this and send it on the same path with intrumentations?
packrat
1 / 5 (3) Jun 07, 2013
If this thing can get through, can we not copy a spacecraft like this and send it on the same path with intrumentations?


Do we even have any spacecraft or rockets capable of traveling as fast as it was going? Otherwise they wouldn't make it all the way around but just crash and burn. Or maybe burn and then crash.........
cantdrive85
1 / 5 (6) Jun 08, 2013
Open field lines? Ummm... Right. Anyway... It's rather quite amazing this snowball's chance in hell didn't cause it to melt. Unless of course, it's not at all anything like a snowball.
yyz
5 / 5 (3) Jun 08, 2013
"It's rather quite amazing this snowball's chance in hell didn't cause it to melt."

Actually Comet Lovejoy was observed to have lost ~10^13 gm in the egress phase of SDO AIA observations: http://arxiv.org/abs/1304.1544

And of course you realize that the complete disintegration of the nucleus of Comet Lovejoy was observed just a few days past perihelion: http://arxiv.org/abs/1205.5839
GSwift7
5 / 5 (3) Jun 10, 2013
If this thing can get through, can we not copy a spacecraft like this and send it on the same path with intrumentations?


Although we cannot build anything that would survive as close as Lovejoy got, we are building a probe which will orbit at less than 4 million miles. It is called Solar Probe Plus, and is scheduled to launch in 2018. It will be the fastest manmade object ever built when it reaches its closest approach to the sun.

http://en.wikiped...obe_Plus

Interestingly, you have to 'slow down' in order to get to the sun. When you leave Earth, you have the angular momentum from Earth's orbital velocity. They will use multiple flyby's of Venus to gradually bleed off angular momentum, until they slow down enough for a stable orbit around the sun.

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.