Posted on by VirtualAstro

Night Sky Guide: February 2012

Special thanks to Ninian Boyle astronomyknowhow.com for information in parts of this guide

This month, the Solar System gives us a lot to observe and we’ll even start to see the ‘spring’ constellations appear later in the evenings. But February still has the grand constellations of winter, with mighty Orion as a centrepiece to long winter nights.

The Sun has finally started to perform as it should as it approaches “Solar Maximum.” This means we get a chance to see the northern lights (Aurora), especially if you live in such places as Scotland, Canada, Scandinavia, or Alaska or the southern light (Aurora Australis) if you live in the southern latitudes of South America, New Zealand and Australia. Over the past few weeks we have seen some fine aurora displays and will we hope to seesome in February!

We have a bit of a treat in store with a comet being this month’s favourite object with binoculars as well, so please read on to find out more about February’s night sky wonders.

You will only need your eyes to see most of the things in this simple guide, but some objects are best seen through binoculars or a small telescope.

So what sights are there in the February night sky and when and where can we see them?

Aurora

Looking north from the science operations center at Poker Fla,Alaska. Credit: Jason Ahrns.

The Aurora or Northern Lights (Aurora Borealis) have been seen from parts of Northern Europe and North America these last few weeks. This is because the Sun has been sending out huge flares of material, some of which have travelled towards us slamming into our magnetic field. The energetic particles then follow the Earth’s magnetic field lines towards the poles and meet the atoms of our atmosphere causing them to fluoresce, similar to what happens in a neon tube or strip light.

The colours of the aurora depend on the type of atom the charged particles strike. Oxygen atoms for example usually glow with a green colour, with some reds, pinks and blues. So the more active the Sun gets, the more likely we are to see the Northern (or Southern) Lights.

All you need to see aurora is your eyes, with no other equipment is needed. Many people image the aurora with exposures of just a few seconds and get fantastic results. Unfortunately auroras are “space weather” and are almost as difficult to predict as normal terrestrial weather, but thankfully we can be given the heads up of potential geomagnetic storms by satellites monitoring the Sun such as “STEREO” (Solar TErrestrial RElations Observatory).

Spaceweather.com is a great resource for aurora and other space weather phenomenon and the site has real-time information on current aurora conditions and other phenomenon.

Planets

Mercury is too close to the Sun to be seen at the beginning of the month, but will be visible very low in the south west from the 17th onwards. At the end of February Mercury will be quite bright at around mag -0.8 and will be quite a challenge. It can be seen for about 30 minutes after sunset.

Venus will improve throughout the month in the south west and will pass within half a degree of Uranus on the 9th of February. You can see this through binoculars or a small telescope. On the 25th Venus and the slender crescent Moon can be seen together a fabulous sight. At the end of month Venus closes in on Jupiter for a spectacular encounter in March.

Venus

Mars can easily be spotted with the naked eye as a salmon pink coloured “star” and starts off the month in the constellation of Virgo and moves into Leo on the 4th. Mars is at opposition on March 3rd but is also at its furthest from the Sun on the 15th February making this opposition a poor one with respect to observing due to its small apparent size. The planet will still be visually stunning throughout the month.

Mars

Jupiter starts off the month high in the south as darkness falls and is still an incredibly bright star-like object. Through good binoculars or a small telescope you can see its four Galilean moons – a fantastic sight. On the 8th at around 19:50 UT, Europa will transit Jupiter and through a telescope you will see the tiny moons shadow move across its surface. Throughout February, Jupiter moves further west for its close encounter with Venus in March.

Jupiter

Saturn rises around midnight in the constellation of Virgo and appears to be a bright yellowish star. Through a small telescope you will see the moon Titan and Saturn’s rings as well.

Saturn

Uranus is now a binocular or telescope object in the constellation of Pisces. On the 9th Uranus and the planet Venus will be within half a degree of each other.

Uranus

Neptune is not visible this month.

Comets

Comet Garradd Credit: astronomy.com

Comet Garradd is still on show early in the month — if you have binoculars — and as the month progresses the viewing should improve. You can find the comet in the constellation of Hercules not far from the globular cluster M92. It is about a half a degree away or around the same width as the full Moon. The comet is around magnitude 7 or a little fainter than the more famous globular cluster M13 also to be found in Hercules, so you will definitely need binoculars to see it. The comet is heading north over the course of the month which should mean that it will become a little easier to see. At the beginning of the month you will have to get up early to see it, the best time being around 5:30 to 6:30 GMT. By the end of the month though, it should be visible all night long.

Moon phases

  • Full Moon – 7th February
  • Last Quarter – 14th February
  • New Moon – 21st February

Constellations

In February, Orion still dominates the sky but has many interesting constellations surrounding it.

Above and to the left of Orion you will find the constellation of Gemini, dominated by the stars Castor and Pollux, representing the heads of the twins with their bodies moving down in parallel lines of stars with each other.

Legend has it that Castor and Pollux were twins conceived on the same night by the princess Leda. On the night she married the king of Sparta, wicked Zeus (disguised as a swan) invaded the bridal suite, fathering Pollux who was immortal and twin of Castor who was fathered by the king so was mortal.

Castor and Pollux were devoted to each other and Zeus decided to grant Castor immortality and placed Castor with his brother Pollux in the stars.

Gemini has a few deep sky objects such as the famous Eskimo nebula and some are a challenge to see. Get yourself a good map, Planisphere or star atlas and see what other objects you can track down.

Credit: Adrian West

 

Posted on by Tammy Plotner

“Cool” Gas May Be At The Root Of Sunspots

During the initial stage of sunspot emergence and cooling, the formation of H2 may trigger a temporary "runaway" magnetic field intensification. The magnetic field prevents the flow of energy from inside the sun to the outside, and the sunspot cools as the energy shines into space. They form hydrogen molecules that take half the volume of the atoms, thus dropping pressure and concentrating the magnetic field, and so on. (adapted from Jaeggli, 2011; sunspot image by F. Woeger et al

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Although well over 40 years old, the Dunn Solar Telescope at Sunspot, New Mexico isn’t going to be looking at an early retirement. On the contrary, it has been outfitted with the new Facility Infrared Spectropolarimeter (FIRS) and is already making news on its solar findings. FIRS provides simultaneous spectral coverage at visible and infrared wavelengths through the use of a unique dual-armed spectrograph. By utilizing adaptive optics to overcome atmospheric “seeing” conditions, the team took on seven active regions on the Sun – one in 2001 and six during December 2010 to December 2011 – as Sunspot Cycle 23 faded away. The full sunspot sample has 56 observations of 23 different active regions… and showed that hydrogen might act as a type of energy dissipation device which helps the Sun get a magnetic grip on its spots.

“We think that molecular hydrogen plays an important role in the formation and evolution of sunspots,” said Dr. Sarah Jaeggli, a recent University of Hawaii at Manoa graduate whose doctoral research formed a key element of the new findings. She conducted the research with Drs. Haosheng Lin, also from the University of Hawaii at Manoa, and Han Uitenbroek of the National Solar Observatory in Sunspot, NM. Jaeggli now is a postdoctoral researcher in the solar group at Montana State University. Their work is published in the February 1, 2012, issue of The Astrophysical Journal.

You don’t have to be a solar physicist to know about the Sun’s 11 year cycle, or to understand how sunspots are cooler areas of intense magnetism. Believe it or not, even the professionals aren’t quite sure of how all the mechanisms work… especially those which cause sunspot forming areas that retard normal convective motions. Of the things we’ve learned, the spot’s inner temperature has a correlation with its magnetic field strength – with a sharp rise as the temperature cools. “This result is puzzling,” Jaeggli and her colleagues wrote. It implies some undiscovered mechanism inside the spot.

NOAA 11131 sunspot region (Dec. 6, 2010) was the most intense spot measured in this study, but far from the largest the Sun can produce. The two bottom images show the strength of the magnetic field (C) and the contrast between the interior of the spot and the surrounding photosphere (D). The first graph (A) shows how OH starts to appear in the penumbra and continues to rise as the magnetic field strength rises. Because OH forms at a lower temperature than H2, its presence implies the quantity of hydrogen molecules that could be present (B). (adapted from Jaeggli et al, 2012)

One theory is that hydrogen atoms combining into hydrogen molecules may be responsible. As for our Sun, the majority of hydrogen is ionized atoms because the average surface temperature is assessed at 5780K (9944 deg. F). However, since Sol is considered a “cool star”, researchers have found indications of heavy-element molecules in the solar spectrum – including surprising water vapor. These type of findings might prove the umbral regions could allow hydrogen molecules to combine in the surface layers – a prediction of 5% made by the late Professor Per E. Maltby and colleagues at the University of Oslo. This type of shift could cause drastic dynamic changes where gas pressure is concerned.

“The formation of a large fraction of molecules may have important effects on the thermodynamic properties of the solar atmosphere and the physics of sunspots,” Jaeggli wrote.

With direct measurements being beyond our current capabilities, the team then measured a proxy – the hydroxyl radical made of one atom each of hydrogen and oxygen (OH). According to the National Solar Observatory, “OH dissociates (breaks into atoms) at a slightly lower temperature than H2, meaning H2 can also form in regions where OH is present. By coincidence, one of its infrared spectral lines is 1565.2nm, almost the same as the 1565nm line of iron, used for measuring magnetism in a spot and one of the lines FIRS is designed to observe.”

Spectral lines are the unique "fingerprints in light" that all atoms and molecules produce. In the presence of a magnetic field in a hot gas, some lines split, betraying the presence and strength of the magnetic fields. Each line corresponds to electrons giving up energy in discrete amounts, or quanta, as light. Imposing a magnetic field on the atom makes the electrons produce multiple lines instead of one. The spread of these lines is a direct measure of the strength of the magnetic field, and is greater in the red and in the infrared spectrum. This image depicts sunspot spectra taken by FIRS with lines centered at 630.2nm (left) and 1564.8nm (right). Note the broadened area in the color ellipses, indicating line splitting inside a spot, and how the broadening is greater at the longer wavelength. Contrast is adjusted to enhance visibility in the inset boxes.

By combining both old and new data, the team measured magnetic fields across sunspots, and the OH intensity inside spots, judging the H2 concentrations. “We found evidence that significant quantities of hydrogen molecules form in sunspots that are able to maintain magnetic fields stronger than 2,500 Gauss,” Jaeggli commented. She also said its presence leads to a temporary “runaway” intensification of the magnetic field.

As for the anatomy of a sunspot, magnetic flux boils up from the Sun’s interior and slows surface convection – which in turns stops cooler gas which has radiated its heat into space. From there, molecular hydrogen is created, reducing the volume. Because it is more transparent than its atomic counterpart, its energy is also radiated into space allowing the gas to cool even more. At this point the hot gas primed by the flux compresses the cooler region and intensifies the magnetic field. “Eventually it levels out, partly from energy radiating in from the surrounding gas. Otherwise, the spot would grow without bounds. As the magnetic field weakens, the H2 and OH molecules heat up and dissociate back to atoms, compressing the remaining cool regions and keeping the spot from collapsing.”

For now, the team admits that additional computer modeling is required to validate their observations and that most of the active regions so far have been mild ones. They’re hoping that Sunspot Cycle 24 will give them more fuel to be “cool”…

Original Story Source: National Solar Observatory News Release.

Posted on by Nancy Atkinson

“Bad Boy” Sunspot Unleashes Powerful X-Class Flare

The active region on the Sun that created all the hubbub and aurorae earlier this week put out one last shot before that area of the Sun turns away from Earth’s view. And that shot was a biggie. At 18:37 UT (1:37 pm EST) today (January 27, 2012) sunspot 1402 unleashed an X-class flare, the largest and most powerful category of flares. This flare was measured as an X2, which is at the low end of the highest powered flares, but still, this is the most powerful flare so far this year. It was not directed at Earth, but scientists from the Solar Dynamics Observatory say the energetic protons accelerated by the blast are now surrounding our planet and a S1-class radiation storm is in progress. S1-class is the lowest of 5 (S1 to S5) and has no biological impact, no satellite operations are impacted but some minor impact on HF radio could be experienced.

With all the activity from the Sun, you might need a refresher course in solar flares. Here’s a guide from SDO, and what all the different classifications are:
Continue reading ““Bad Boy” Sunspot Unleashes Powerful X-Class Flare”

Posted on by Nancy Atkinson

What Causes Aurora?

Will you be seeing an aurora tonight? Yesterday, January 23, 2012, an M8.7-class flare erupted from the Sun and sent a huge wave of high-energy protons towards Earth and Mars, moving at about 8 million kilometers per hour. According to Spaceweather.com, the CME hit Earth’s magnetic field at approximately 1500 UT (10 am EST) today, and geomagnetic storms are likely in the hours ahead, as scientists say this the largest solar storm Earth has encountered since 2005.

But what is an aurora and what causes them?
Continue reading “What Causes Aurora?”

Posted on by Jason Major

Can Solar Flares Hurt Astronauts?

Expedition 29 astronaut Ron Garan looks down on the coast of Australia from the safety of the ISS. (NASA)

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Solar flares, coronal mass ejections, high-energy photons, cosmic rays… space is full of various forms of radiation that a human wouldn’t want to be exposed to for very long. Energized particles traveling into and through the body can cause a host of nasty health problems, from low blood count to radiation sickness to cataracts and cancer… and potentially even death. Luckily Earth’s magnetic field and atmosphere protects us on the surface from much of this radiation, but what about the astronauts aboard the Space Station? How could events such as today’s powerful near-X-class solar flare and last week’s CME affect them, orbiting 240 miles above Earth’s surface?

Surprisingly, they are safer than you might think.

M8.7-class solar flare erupting on the Sun's northeastern hemisphere at 03:49 UT on Jan. 23, 2012. (Courtesy NASA/SDO and the AIA team. Edited by J. Major.)

The M8.7-class flare that erupted from the Sun early on Jan. 23 sent a huge wave of high-energy protons Earthward, creating the largest solar storm seen since 2005.  The cloud of energetic particles raced outwards through the Sun’s atmosphere at speeds well over a million miles per hour, blowing past our planet later the same day. (More slower-moving charged particles will impact the magnetosphere in the coming days.) We are safe on Earth but astronauts exposed to such radiation could have faced serious health risks. Fortunately, most solar protons cannot pass through the hull of the Space Station and so as long as the astronauts stay inside, they are safe.

Of course, this is not the case with more dangerous cosmic rays.

According to the NASA Science site:

Cosmic rays are super-charged subatomic particles coming mainly from outside our solar system. Sources include exploding stars, black holes and other characters that dwarf the sun in violence. Unlike solar protons, which are relatively easy to stop with materials such as aluminum or plastic, cosmic rays cannot be completely stopped by any known shielding technology.

Even inside their ships, astronauts are exposed to a slow drizzle of cosmic rays coming right through the hull. The particles penetrate flesh, damaging tissue at the microscopic level. One possible side-effect is broken DNA, which can, over the course of time, cause cancer, cataracts and other maladies.

In a nutshell, cosmic rays are bad. Especially in large, long-term doses.

Now the astronauts aboard the ISS are still well within Earth’s protective magnetic field and so are shielded from much of the cosmic radiation that passes through our solar system daily. And, strangely enough, when solar flares occur – such as today’s – the amount of cosmic radiation the ISS encounters actually decreases.

Why?

The solar particles push them away.

Decrease in cosmic radiation during a CME recorded in 2005.

In an effect known as the “Forbush decrease”,  magnetically-charged particles ejected from the Sun during flares and CMEs reduce the amount of cosmic radiation the ISS experiences, basically because they “sweep away” other charged particles of more cosmic origin.

Because cosmic rays can easily penetrate the Station’s hull, and solar protons are much less able to, the irony is that astronauts are actually a degree safer during solar storms than they would be otherwise.

And it’s not just in low-Earth orbit, either: Wherever CMEs go, cosmic rays are deflected. Forbush decreases have been observed on Earth and in Earth orbit onboard Mir and the ISS. The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft have experienced them, too, beyond the orbit of Neptune. (via NASA Science.)

Due to this unexpected side effect of solar activity it’s quite possible that future manned missions to the Moon, Mars, an asteroid, etc. would be scheduled during a period of solar maximum, like the one we are in the middle of right now. The added protection from cosmic rays would be a big benefit for long-duration missions since we really don’t know all the effects that cosmic radiation may have on the human body. We simply haven’t been traveling in space long enough. But the less exposure to radiation, the better it is for astronauts.

Maybe solar storms aren’t so bad after all.

Read more about solar radiation and the Forbush decrease on NASA Science here.

Posted on by Nancy Atkinson

NOAA: Largest Solar Radiation Storm Since 2005 Now in Progress

X-Ray image from a GOES satellite at 14:12 UTC on January 23, 2012. Credit: NOAA

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Earth’s magnetic field is already full of activity from an Earth-directed Coronal Mass Ejection (CME) last week. But all indications are another blast is headed our way from the strongest solar radiation storm since September, 2005. NOAA says the storm is currently in progress and continues to get stronger, with a very fast CME headed towards Earth. Sunspot 1402 erupted, producing a long-duration M9-class solar flare. “Geomagnetic storming is a near certainty from this event,” reported NOAA. The associated solar flare peaked at about 0400 UTC on January 23 (11pm Jan 22 EST).”

A computer model just released by NOAA’s Space Weather Prediction Center forecasts the storm will arrive sometime on January 24, at about 14:18 UT (+/- 7 hours), as the CME is traveling at approx. 2,200 km per second. Click here to see the animated model.

We’ve already shown you a video of the auroral activity going on yesterday and will soon post a gallery of beautiful aurorae from around the world. And it looks like we’ll likely have more photos to share in the coming week! And NASA says skywatchers should be on the lookout for aurora in lower than normal latitudes. Scientists are also predicting that Mars will get hit too, several hours after Earth. At this point, there’s no way to predict the possible effect on Earth-orbiting satellites for communications, GPS, etc, or the effect on Mars spacecraft.

These kinds of events can cause problems for spacecrafts in geosynchronous, polar and other orbits passing could be affected by the cloud’s arrival. In addition, strong geomagnetic storms are possible, so high-latitude sky watchers should be alert for aurorae.

Below is a video from the Solar Dynamics Observatory of the event:

Posted on by Nancy Atkinson

Aurora Alert! Sun Sends CME in Earth’s Direction

As seen here by the Solar Dynamics Observatory, a long duration M3-class flare began erupting on the Sun from sunspot region 1401 at 13:42 UTC (8:42 AM ET) today, Thursday, January 19, 2012, sending a coronal mass ejection (CME) directly towards Earth. Scientists predict the CME will arrive at around 16:00 UTC on January 21, 2012 GMT. Spaceweather.com says strong geomagnetic storms are possible and high-latitude (and possibly middle-latitude) skywatchers can be on the lookout for increased aurora.

Continue reading “Aurora Alert! Sun Sends CME in Earth’s Direction”

Posted on by Tammy Plotner

I Thought I Saw A UFO! Mystery Triangle On STEREO Image Explained…

Here is a diagram showing the location of the various features in the image. Credit: NASA

Mystery diamond-shape “object” entering the field-of-view of the HI2 telescope on STEREO Behind around December 26, 2011. Credit: NASA

The STEREO (Solar TErrestrial RElations Observatory) is a two-year mission conducted by NASA. It employs nearly identical twin telescopes – one positioned ahead of Earth’s orbit and the other behind – designed to study the Sun’s activities spectroscopically. However, it can sometimes pick up some very unusual findings! On December 26, 2011, the STEREO Behind Observatory’s HI2 telescope captured an ambiguous triangle entering the field of view and moving from right to left just above the trapezoidal occulter as seen in the above movie. Just what is this “thing”?!

Before you get ready to call the men in black, know that there is a logical answer… and it comes into play on the opposite side of the STEREO image. Play the movie again and watch. (It’s a bit more obvious in this close-up view.) Just as the weird triangle begins its approach, you’ll notice the dazzling Venus enters the field of view of the HI2-B at the same time to the lower left. As you watch, you’ll see they keep exactly the same time – in opposite – across the detector image. This isn’t just a chance happening… it’s a naturally-occurring internal reflection caused by Venus’ brilliance in the telescope’s optics. It might be exciting for the moment, but it’s nothing that hasn’t happened in the past. Just check out these great STEREO Reflections of Earth, and all sorts of other cool images on the STEREO Image Artifacts pages.

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What else can be seen? As you can tell from this photograph, Earth is also starring in the show, but doesn’t come in as striking as Venus. What’s more you can also see the tail of Comet Lovejoy streaking in from the left just above Venus towards the end of the movie.

Exactly how do you keep track of what’s going on? Check out the Where Is STEREO? pages for up-to-date information and the totally cool Current STEREO Solar Images!

Original Story Source: Triangular shaped object in STEREO data explained.

Posted on by Nancy Atkinson

The Sun Blows Off a Little Steam

A close-up look at the Sun on the last day of 2011, showing impressive multiple prominences with sunspots AR1389 at the eastern limb. Credit: Efrain Morales Rivera, Jaicoa Observatory

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This is an awesome image of the Sun captured by Efrain Morales Rivera from the Jaicoa Observatory in Aguadilla, Puerto Rico, on December 31, 2011. It shows multiple steam-like prominences on the eastern limb of the Sun. Rivera compared them to a group of trees, and said the now-active Sun is definitely something to watch in the coming new year. Of course, the Solar Dynamics Observatory is keeping a close watch on our star, and captured a huge eruption on the western limb of the Sun on January 2, 2012, with lots of solar material ejected into space; however, it was not Earth-directed. See the video below: