An Exoplanet’s Auroral Engine

Aurora like the ones seen on October 24, 2011 as far south as Texas and Georgia would be commonplace on CoRoT-2b. (Image from the all-sky AuroraMax camera in Yellowknife, Ontario. http://twitpic.com/75owna )


Located 880 light-years away, a massive gas giant called CoRoT-2b orbits its star at a mere 2 million miles – less than a tenth the distance of Mercury’s orbit from the Sun. At this cozy proximity the star, CoRoT-2a, continually assaults the hot, gassy exoplanet with high-powered stellar winds and magnetic storms, stripping it of millions of kilograms of mass every day… and undoubtedly creating global auroras that rival even the most energetic seen on Earth.

But CoRoT-2b isn’t merely a tragic player in this stormy stellar performance; the planet itself may also be part of the cause.

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Almost 3 1/2 times the mass of Jupiter, CoRoT-2b (so named because it was discovered by the French Space Agency’s Convection, Rotation and planetary Transits space telescope, or CoRoT) orbits its star very rapidly, completing an orbit every 1.7 days. This in turn actually speeds up the rotation of the star itself thus generating even more magnetic activity, via a dynamo effect.

Caught up in this deadly dance, CoRoT-2b is losing mass at an estimated rate of 150 million billion kilograms of material every year! The planet would likely have a long comet-like tail of this stripped material trailing behind it.

Although this sounds like a lot, CoRoT-2b has enough mass to keep “spinning up” its star for thousands of billions of years.

Read more about CoRoT-2a and b here.

Video: Science@NASA

Spooky Halloween Aurora

A spooky Halloween aurora! Credit: Jason Ahrns.

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Did you see ghosts and goblins last night for Halloween? Jason Ahrns of Chatanika, Alaska saw a dark shadow of a spooky ghost in the middle of a green aurora stream during his observing run on October 31, 2011. He used a Nikon D5000 to snap this eerie image.

See more from Jason at his Flickr page.

Want to get your astrophoto featured on Universe Today? Join our Flickr group, post in our Forum or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Reader Pics: CME Spawns Awe-Inspiring Bright Red Aurorae

Bright red aurora seen in South Dakota. Credit: Randy Halverson, Dakotalapse.com

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Now updated with more images and video! Reports of spectacular aurora are coming in! A CME hit Earth’s magnetic field on Oct. 24, 2011 at about 1800 UT (02:00 pm EDT), spawning some stunning red sky shows. All-red aurorae are fairly rare, and are produced by high-altitude oxygen, at heights of up to 200 miles, being excited by collisions from charged particles released from the Sun.

Above is the view by Randy Halverson, of Dakotalapse.com fame, whose work we feature often on UT. He’s not in his usual location of South Dakota, but is in Wisconsin, along with his son River Halverson. Randy said via Twitter that the brightest aurora he saw was about 8:25 or so local time (CDT).

Oct. 24, 2011 aurora seen in Yellow Springs, Ohio. Credit: John Chumack

John Chumack is another astrophotographer whose work we feature often. Here’s one of his shots of the Aurora Borealis on 10-24-2011 from John Bryan State Park, near Yellow Springs, Ohio. “30 second exposure, ISO 400, 8mm fisheye lens,” John says. See more from him on his website, Galactic Images (and he uploads frequently to our Flickr group, too!)

Taken from a driveway in northern Ohio on October 24, 2011. Credit: Joe Lloyd

Joe Lloyd from northern Ohio took this image from his driveway!

Aurora in Wichita, Kansas USA. Credit: Jim Hammer via Flickr.

Aurora reaching fairly far south in Kansas!

Below is a video from East Martin, Michigan posted on You Tube:

Aurora in Wisconsin. Credit: River Halverson and Randy Halverson from Dakotalapse

Another from Randy Halverson.

Image from the all-sky AuroraMax camera in Yellowknife, Ontario. http://twitpic.com/75owna

This is an image from the AuroraMax all-sky camera located in Yellowknife, Ontario Canada. If you can’t see aurora where you are located, you can always check out the live video every night from AuroraMax,

Here’s the event on the Sun that started it all, the coronal mass ejection (CME) that caused aurora. The SOlar Heliospheric Observatory (SOHO) captured this “coronograph” – so-called because the images block the Sun, and only show the Sun’s atmosphere, or corona.

You can see more on Universe Today’s Flickr Group. Upload your images, and we may feature them!

The Meteor and the Nordlys

Photo of the northern lights over northern Norway by Adon Buckley.

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A meteor slices through the glow of the northern lights (or “Nordlys”) in this photo by Adon Buckley, taken near the border of Norway and Finland on the night of October 19, 2011.

“The weather was against us, it was raining heavily in the northern Norwegian town of Tromsø,” Adon describes on his Flickr page. “We drove for 2 hours and waited on the Norwegian/Finish border for 3 more and this was at the start of the show on October 19th.”

He adds, “I actually missed the shooting star when it happened, but my friend told me and I was eager to check the exposure when I got home.”

Great catch, Adon! And a wonderful photo as well.

See more of Adon’s photos on his Flickr photostream here.

Image © Adon Buckley. Used with permission.

What is Airglow?

Recent photo from the ISS showing the airglow layer

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In many of the photos that we have featured recently from astronauts aboard the International Space Station, a glowing greenish-yellow band can be seen just above Earth’s limb. I’ve been asked before what this is, so I thought I’d explain it here. This is a phenomenon known as “airglow”.

A photochemical reaction that occurs high in the atmosphere, airglow is the result of various atoms, molecules and ions that get excited (chemistry-excited, that is… not “whee!”-excited) by ultraviolet radiation from the Sun and then release that energy as visible – as well as infrared – light when they return to their “normal” state. It’s not entirely unlike glow-in-the-dark toys or paint!

This light is most visible to the crew of the ISS when it is orbiting over the night side of the planet, and thus is seen in images like the one above. It appears like a thin band because viewing the atmosphere at a shallow angle – rather than directly down through it – increases the airglow layer’s relative visibility.

Most of visible airglow comes from oxygen atoms and molecules, which glow green… as commonly seen in the aurora. Other contributing elements include sodium and nitrogen. While present in the atmosphere at all layers, the region that glows visibly is typically constrained to a narrow band 85 – 95km (53-60 miles) high. The band itself is usually about 6 – 10km (4-6 miles) wide. The reason for this is that below those heights the atoms and molecules are more concentrated and collide more readily, releasing their energy sooner, and above it the density of the atoms is too low to do much colliding at all (to put it very simply.)

There are a lot of other factors involved with airglow as well, such as temperature and altitude, as well as different kinds of airglow depending on when in the day they occur. Nightglow is not exactly the same as dayglow, and then there’s even twilightglow… one could say there’s a lot glowing on in the upper atmosphere!

I’m here all week, folks.

You can read more about airglow in this informative article by the Institute of Astronomy and Astrophysics (Instituto de Astronomía y Física del Espacio) in Buenos Aires. Image credit: NASA.

 

Fires in the Sky, Fires on the Ground

The aurora australis seen from the ISS on September 17, 2011. Credit: NASA.

 

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With all of the activity that’s been occurring on the Sun recently, the aurorae have been exceptionally bright and have created quite a show to viewers – both on Earth as well as above it!

The image above was taken over the southern Indian Ocean by astronauts aboard the International Space Station. The southern lights – a.k.a. aurora australis – glow bright green and red in the upper layers of the atmosphere, creating a dazzling aerial display. (Click here to watch a movie of this.)

Shortly after, fires can be seen on the ground as the ISS passes over Australia:

Wildfires in Australia seen from orbit. Credit: NASA.

From NASA’s Earth Observatory website:

Astronauts on the International Space Station (ISS) used a digital camera to capture several hundred photographs of the aurora australis, or “southern lights,” while passing over the Indian Ocean on September 17, 2011. You can see the flowing ribbons and rays below as the ISS passed from south of Madagascar to just north of Australia between 17:22 and 17:45 Universal Time. Solar panels and other sections of the ISS fill some of the upper right side of the photograph.

Auroras are a spectacular sign that our planet is electrically and magnetically connected to the Sun. These light shows are provoked by energy from the Sun and fueled by electrically charged particles trapped in Earth’s magnetic field, or magnetosphere. In this case, the space around Earth was stirred up by an explosion of hot, ionized gas from the Sun — a coronal mass ejection — that left the Sun on September 14, 2011.

In the second image above, and in the last frames of the movie, light from the ground replaces the light show in the sky. Wildfires and perhaps some intentionally set agricultural fires burn on the continent of Australia,with smoke plumes faintly visible in the night sky. A gold and green halo of atmospheric airglow hangs above the horizon in the distance.

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Airglow is created by particles in the upper atmosphere that have been charged by UV light from the Sun during the day releasing the energy at night as greenish-yellow visible light.

Fires on the ground, fires in the sky… the stars blazing all around, the Sun in its full glory and a never-ending view of our entire planet… what an incredible place the ISS must be to work in! Absolutely amazing!

And the skies of night were alive with light, with a throbbing, thrilling flame; Amber and rose and violet, opal and gold it came. It swept the sky like a giant scythe, it quivered back to a wedge; Argently bright, it cleft the night with a wavy golden edge.

— “The Ballad of the Northern Lights”, Robert Service

Read more on the NASA Earth Observatory.

Red Alert! Space Station Aurora

Astronauts on the International Space Station had this view of the aurora on September 26, 2011. Credit: NASA

Astronauts had this view of the aurora on September 26, 2011. Credit: NASA

We’ve had some great views of the aurora submitted by readers this week, but this one taken from the International Space Station especially highlights the red color seen by many Earth-bound skywatchers, too. Karen Fox from the Goddard Space Flight Center says the colors of the aurora depend on which atoms are being excited by the solar storm. In most cases, the light comes when a charged particle sweeps in from the solar wind and collides with an oxygen atom in Earth’s atmosphere. This produces a green photon, so most aurora appear green. However, lower-energy oxygen collisions as well as collisions with nitrogen atoms can produce red photons — so sometimes aurora also show a red band as seen here.

Source: Goddard Space Flight Center Flickr

An Easy Guide To Observing the Aurora

Dundee Aurora Credit: Ben-e-boy

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With the recent solar activity and the high possibility of more coming up, here is an easy guide to observing the aurora. An aurora is a natural light display high in the Earth’s atmosphere, caused by energetic particles from the Sun, colliding with the Earth’s magnetic field.

These light displays are called the Aurora Borealis in the Northern hemisphere and Aurora Australis in the Southern hemisphere, but are commonly known as the Northern and Southern lights.

Viewing aurorae is incredibly simple, but the conditions need to be right for a display to appear.

Normally you can only see aurorae near the poles, such as in Canada, Iceland, and Norway or southern Australia and Antarctica, but when the Sun is highly active, more solar material is thrown in Earth’s direction, creating powerful geomagnetic storms. These storms can bring auroral displays further south to areas such as Southern UK and North to mid latitudes of the USA.

The intensity scale is known as the Planetary KP index and basically the higher the KP number the further south Aurorae can be seen, KP 8 or higher can be good for observers further south. To find out what current levels are check spaceweather.com or the Geophysical Institute at the University of Alaska Fairbanks

Credit spacewether.com

If aurora activity is predicted to be high and there is a possibility of seeing it at your location, try and find an area away from light pollution or bright lights and let your eyes adjust to the dark. This may require you to travel into the countryside to escape bright city light pollution.

The best time to spot aurora is around local midnight, but this can change depending on viewing conditions and the current intensity of the magnetic storm.

Once you are comfortable and your eyes have adjusted to the dark, face north (or south in the Southern Hemisphere).

You do not need binoculars, a telescope, or any other optical aid other than glasses if you wear them.

Look low and close to the horizon and look for the faint green/ reddish glow of aurora. It may be quite difficult to see at first, but if it is a powerful display it can be very easy to spot.

I live in the South of the UK and have seen the waving bands and curtain like structures quite easily in powerful geomagnetic storms.

If you have a camera that takes long exposures, use a tripod and try to image the aurora and send us your results.

Most of all, enjoy the show! Good luck!

Aurora caught over Karlstad, Sweden on September 27, 2011. Credit: Socrates2013 on Flickr

Aurora September 26, 2011 From Acadia National Park Credit: hale_bopp37
Aurora Behind the Clouds Credit: Corinne Mills