3-D Ring Nebula reveals its “inner jelly doughnut”

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How absolutely beautiful. This composite image of the Ring Nebula made combines views with the  Hubble Space Telescope with a picture of the nebula’s  outer halo from the Large Binocular Telescope (LBT) in Arizona. Click to enlarge. Credit: NASA, ESA, C. Robert O’Dell (Vanderbilt University), and David Thompson

After the moon and planets, the Ring Nebula must be one of the top three deep sky objects sought out by astronomers of all stripes. Many a spring and summer night I’ve made my “pilgrimage to the Ring”. And why not? It’s easy to spot not far from the brilliant star Vega in the constellation Lyra and looks like a smoke ring frozen in time.

To find the Ring Nebula, first locate Vega, the uppermost and brightest star of the Summer Triangle asterism. It’s well placed in the east at nightfall in late May. The Ring is midway between the two stars in the bottom of Lyra’s figure. Created with Stellarium

The Ring Nebula was discovered in a 2.5″ refracting telescope by Antoine Darquier de Pellepoix in 1779. He described it as “a very dull nebula, but perfectly outlined; as large as Jupiter and looks like a fading planet.” Not long after, famed French comet hunter Charles Messier stumbled on while tracking a new comet across the sky. Messier promptly added it to his catalog of fuzzy things that resemble comets, dubbing it M57.

In small telescopes, the Ring looks like a round, pale-gray smoke ring with a dark center. Larger amateur scopes show its elliptical shape and thin veil of gas across the dark opening. Credit: Jim Misti

Located about 2,000 light years from Earth and spanning nearly one light year (6 trillion miles) end to end, our entire solar system would fit inside the doughnut hole with room to spare. The Ring is one of many planetary nebulae, so called because their rounded shapes reminded early telescopic observers of planets.

Planetaries are the cast-off mantles and atmospheres of sun-sized stars when they run out of fuel in their cores. What’s left is an exceedingly hot, planet-sized core called a white dwarf star. The gassy remains fluoresce green, red and blue in the flood of energetic ultraviolet light radiating from the dwarf. Each color represents a different element; oxygen glows green, helium blue and nitrogen red.

The Ring Nebula is situated between Gamma and Beta Lyrae in the constellation Lyra the Harp. Its shape can be seen in almost any small telescope; binoculars show it as a slightly fuzzy “star”. Credit: NASA/ESA/Digitized Sky Survey 2

The nebula’s expanding at the fantastic speed of 43,000 mph (69,000 kph) but because of its great distance won’t show a whit of difference in size during a human lifetime. But 10,000 years from now, the Ring will have grown so large and faint it will merge with the interstellar medium, the thin soup of gas between the stars from which future generations of stars are born.

While the nebula looks like a bagel with a thick doughy exterior and empty center, it’s more like a jelly doughnut. In a small telescope, the center appears empty but larger scopes reveal that its interior is filled with less dense gas. Astronomers have combined ground-based telescopic views with new observations using the Hubble Space Telescope to give us a clear three-dimensional understanding of what we’re seeing.

We gaze directly down at the Ring Nebula from here on Earth (top perspective) and see the brightest part of the nebula as the colorful ring. This side-on view shows the nebula’s wide halo, inner region, lower-density “rugby ball” of material stretching towards and away from us, and the prominent, glowing disk. Credit: NASA, ESA, and A. Feild (STScI)

“We are gazing almost directly down one of the poles of this structure, with a brightly colored barrel of material stretching away from us. Although the center of this doughnut may look empty, it is actually full of lower density material that stretches both towards and away from us, creating a shape similar to a rugby ball slotted into the doughnut’s central gap,” says a recent NASA/ESA release on the topic.

In other words, there’s much more there than meets the eye. With only one perspective – we’re stuck on Earth after all – the nebula’s “inner jelly doughnut” self required careful observation and data-teasing to fathom. The next time we point our scopes in the Ring’s direction we can enjoy and appreciate it from a new perspective.

Ecuador’s only satellite crippled in crash with Russian space debris

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3D stereo simulation of the Pegasus satellite colliding with old Russian SL-14 rocket booster debris over the ocean above Madagascar. To see the stereo view, cross your eyes until the two images merge. The 3D effect is striking. Click for more images. Credit: Simone Corbellini

Russian rocket debris appear to have collided with Ecuador’s only satellite early Thursday morning 932 miles (1,500 km) above the Indian Ocean east of Madagascar. This according to Ecuador’s space agency chief Ronnie Nader.

Pegaso (Pegasus), a cube-shaped nanosatellite measuring just 4 x 4 inches (10×10 cm) on a side and weighing 2.6 lbs (1.2 kg) was designed and built in Ecuador and launched from China on April 25. The tiny bird takes pictures and video from orbit and transmits them back to Earth.

Model of the Pegaso nanosatellite with solar arrays. Credit: Wikipedia

Pegasus was not struck directly by the decades-old Soviet rocket booster but by a nearby cloud of debris associated with it. The good news is that the satellite is still orbiting Earth; the bad news is it’s most likely damaged and spinning out of control. It’s been reported on the Web-based Seesat-L list that the Argentinian satellite Cubebug-1 may have also been hit.

Give the amount of space junk in orbit, it’s no surprise hits like this are becoming more commonplace. 19,000 pieces 2-inches (5 cm) or larger are currently being tracked with over 300,000 pieces smaller than a 1/2″ (1 cm) orbiting below 1,240 miles (2000 km).

It will take at least two days using radar to determine the extent of the damage. In the meantime, you might want to stop by the Ecuadorian Civilian Space Agency (EXA) site responsible for the Pegasus program. It’s the only the space agency I’m aware of that uses popular a rap song in its promotion.

Ecuador plans to launch its second satellite named Krysaor from Russia this July. More on the story HERE.

Chance of auroras tonight May 23-24

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Click to see a video showing a nice variety of views of the May 22 flare from the space-based solar observatories SDO and SOHO. 
A strong M5-class flare from sunspot region 1745 on May 22 sent a sideways blast of material from the sun into space. A portion of it is expected to brush past Earth overnight and possibly spark auroras. There’s a 20% chance for a minor auroral storm for mid-latitudes and a 55% chance of a major storm at high latitudes. Tomorrow night that drops to 15% / 30%.

According to Spaceweather.com  the smack down happens around 7 a.m. Central time tomorrow morning May 24. Don’t take that too literally – the ebb and flow of solar particles and their success in circumventing Earth’s protective magnetic field to create an aurora can make times a bit unpredictable.

Complicating viewing forecasts is the nearly full moon; its light can easily wash away a modest aurora. So it sounds like I’m discouraging you, but I’m really not. Keep an eye on the Kp index (an indicator of potential auroral activity) and the auroral oval. If the index jumps into the red where Kp=5 or greater, consider stepping outside for a look.

3 bright planets slow jam at dusk this week

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Jupiter, Venus and Mercury last night 35 minutes after sunset low in the northwestern sky. Details: 150mm lens at f/2.8, 1/30″, ISO 400. Photo: Bob King

Last night we finally cleared off after four solid days and nights of gray and rain. Sparkling low in the northwestern sky was a most welcome sight – Venus, Jupiter and Mercury. This week they will undergo to a series of remarkable gatherings in the early evening sky.

Venus leaped out immediately as the brightest of the trio. It stood 6 degrees above the horizon; that’s three fingers held horizontally at arm’s length. Jupiter jumped out next some 5 degrees to the upper left of Venus. Mercury, the dimmest of the the bunch, was very easy in binoculars but took a bit of concentration to see with the naked eye.

I’ve highlighted several nights of the triple planet gathering over the coming nights. Jupiter is colored yellow and Mercury pink to tell which is which. Created with Stellarium

This jam has just begun. Watch over the coming nights as the three planets move closer together to form a series of ever-changing jeweled triangles. Tomorrow night Mercury and Venus will be closest (1.4 degrees); Mercury and Jupiter on Memorial Day (2.3 degrees) and Venus and Jupiter on May 28 (1 degree).

All you need to see them is an unobstructed view to the west-northwest. You can begin your search about 30 minutes after sunset; get an early start because the planets set about an hour later. Binoculars can prove most helpful in case the sky’s hazy or if you have difficulty finding Mercury.

Left: If you could hover high above Earth’s north pole today and look down on the solar system, this is how the evening planets would be laid out. You can easily see how far they are from one another. At right, viewed from the flat plane of the solar system, they appear to bunch up. These occasional bunches caused by perspective are called conjunctions. Illustration: Bob King

As you can see from the nightly maps,  Mercury moves upward from the western horizon to join Venus, passes it and then teams up with Jupiter. Mercury moves rapidly because it orbits the sun most closely. Venus is also moving up from the west but more slowly, so it essentially stays in the same spot. Jupiter meanwhile drops down toward the western horizon. Earth’s motion around the sun is much faster than Jupiter’s causing the sun to literally “get in the way” between our two planets. From our perspective, Jupiter will soon disappear in the solar glare and won’t be seen again until early July when it reappears in the morning sky.

Although the trio may appear close to one another in the sky, they’re millions of miles from each other and the Earth. We see them together because they lie along the same line of sight for the coming week.

Full Flower Moon ready to bloom plus see an “invisible” eclipse

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The moon marches south toward the bright star Antares over the next three nights. Tonight you’ll find it near the planet Saturn and star Spica. The map shows the sky around 10 p.m. local time. Maps created with Stellarium

Tonight’s waxing gibbous moon will pass south of Saturn on its way to Friday’s Full Flower Moon. Consider it a prelude to an upcoming stellar cover-up and a curious lunar eclipse.

May is the time of year when the moon takes a noticeably southward path across the sky; this month’s full moon hangs low compared to the high moons of winter. That’s because the full moon is always opposite the sun in the sky. When the sun is higher up – as it is in the early summer months – the moon occupies the lower regions of the sky where the sun spends the winter.

The moon will pass in front of the bright star Beta Scorpii Friday during early evening hours for a large swath of the U.S. and Central America. For many of us, the occultation will be over once the moon gets reasonably high in the sky, but you can still enjoy the sight of Beta in binoculars just off the moon’s northern edge.

Two interesting celestial events happen Friday night. First, the moon will occult or cover up the bright star Beta in the constellation of Scorpius the Scorpion. This star lies directly above Antares and isn’t visible on the wide map. The tighter view shows just how close it will be to the moon for much of the Americas and Canada during early evening hours. Friday. In fact, observers south of a line from Thunder Bay, Ontario to New York City will see the moon occult the star at or shortly after moonrise. To find out if you’re in the occultation zone, check this map.

Beta Scorpii is a very pretty double star for small telescopes. If you have a scope, see how close you can follow the star until it disappears behind the edge of the moving moon.

The southern edge of the full moon grazes Earth’s outer shadow for Eastern hemisphere observers early Saturday morning May 25. Credit: Wiki with my own additions

Western hemisphere sky watchers might (or might not) see a penumbral lunar eclipse that begins an hour or two after Friday’s occultation. Penumbral eclipses occur when the moon passes through Earth’s outer shadow called the penumbra; they’re nowhere near as dramatic as when it moves through the much darker, inner umbral shadow.

Eclipse visibility map. The entire event is visible in the white area. Click for more information. Credit: NASA / Fred Espenak

This eclipse will be particularly wimpy with the moon barely dipping its toes in the pool. At maximum, only 1.6% of the moon will be covered by the lightest portion of shadow. I doubt anyone will notice, but why not give it a try anyway? You never know, right? Viewing times are below. It will also be visible in western Europe and Africa. Please note the event lasts only 33 minutes!

* Start of eclipse – 10:53 p.m. Central time
* Maximum eclipse – 11:10 p.m.
* End of eclipse – 11:27 p.m.

Lots of fun in store for the weekend. Tomorrow we’ll look at the gang of planets assembling in the western sky after sunset.

Are there waves on Titan’s Ligeia Sea?

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Titan’s Ligeia Mare, a sea of liquid ethane and methane 260 miles (420 km) across, is comparable to Lake Superior on Earth – with a difference. The “water” in Ligeia Sea is liquid ethane and methane. Credit: NASA

Cassini will soon make its next flyby of the planet’s largest moon Titan to look for waves on the surface of Ligeia Mare (lie-JEE-uh MAH-ray), a large sea of bitterly-cold liquid ethane in the moon’s north polar region.

Titan’s great distance from the sun ensures that the average temperature there hovers at -290 F (-179 C), cold enough for ethane and methane, which are gases here on Earth, to condense as liquids.

On May 23, the probe will cruise just 603 miles (970 km) above the lake and bounce radio waves off its surface to fathom its surface texture. No one’s sure if the liquid natural gas is thick and flat like molasses or more like lake water here on Earth. Will we someday find rapids, waterfalls? I’m hoping for some cool images of waves. Row, row, row your boat.


Watch as Saturn’s B-ring, the bright ring at upper right, expands and contracts. 39 images taken over 1 hour and 40 minutes were used to create the video.

Also on Cassini’s to-do list was the creation of a movie of Saturn’s bright B-ring in order to better understand how the planet’s moons shape its rings. In the video, you can see the ring expand and contract. Look closely and halfway through the movie you’ll also notice an arc of brighter material sweep by just within the ring’s edge. High-resolution pictures show vertical structures in the ring plane here towering up to 2.2 miles (3.5 km) high.

What you’re seeing are ring particles – made of water ice – hovering above the ring plane. As they stream past an invisible moonlet embedded in the B-ring, the moon’s gravity temporarily squeezes them together and lifts them up to form an orbiting arc. The moonlet – estimated at 1,000 feet (300 m) across, was found sometime later, betrayed by the shadow it cast when Saturn’s rings were “level” with the sun at its 2009 equinox.


A low-angle view of Saturn’s B-ring (foreground) made by Cassini. Watch as it swells outward and then shrinks inward.

In the second video, the low-angle perspective makes the expansion and contraction of the B-ring even easier to see. Scientists have found four separate, independent movements of ring particles that create the hula-hoop-like wobble.

The repeated pulls of the inner moon Mimas on B-ring particles as they orbit Saturn creates one of the swellings. The other three travel around the ring with different speeds and are caused when random motions of icy ring particles reinforce one another to create a wave that flows outward to the boundary of the B-ring. From there it’s reflected back to the inner part of the ring, which in turn reflects it out again like waves bouncing around in a bathtub. Repeated back-and-forth bounces cause sections of the B-ring to expand and contract to the tune of 120 miles (200 km).

Small pieces of ice. Amazing what they’re capable of when their random motions work in tandem. Even the 15,800 mile (25,500 km) B-ring must bow (and bend) to their will.

 

Don’t let Comets PANSTARRS and Lemmon out of your sight … yet

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Comet L4 PANSTARRS on May 18. The anti-tail extends straight out from the comet’s coma to the left. Use the map below to find the comet. Click to enlarge. Credit: Michael Jaeger

What the heck have comets L4 PANSTARRS and Lemmon been up to anyway?  Well, they’re still visible in 50mm binoculars and small telescopes. You can see them both sans moonlight in the morning sky after moonset. PANSTARRS first shows at nightfall not far from the North Star Polaris, one reason why it’s easy to find.

Map showing Comet C/2011 L4 PANSTARRS’ location tonight through June 21. Positions are marked off every three nights. Stars are shown to about magnitude 8. Credit: created with Chris Marriott’s SkyMap software

Shining at around 8th magnitude it looks like a fuzzy spot in binoculars, a bigger fuzzy spot with a brighter head in a small scope and a twin-tailed wonder in large amateur telescopes. It sidles up the Little Dipper in the coming month passing near that constellations two brightest stars – Polaris and then Kochab (KO-kab). Moonlight will soon compromise evening viewing but morning skies are still dark just before dawn.

Comet C/2012 F6 Lemmon on May 17 showing its short, diffuse dust tail (left) and long gas tail. Credit: Damian Peach

Michael Jaeger’s amazing photo shows how drastically different PANSTARRS looks compared to a month ago. The principle dust tail (off to the right and fanning left) so bright in March and early April has shrunk and faded. Meanwhile, the anti-tail, formed by dust trailing in the comet’s orbit, stretches at least a full binocular field of view to the left. PANSTARRS never ceases to amaze.

This map shows the sky facing east around 3:30 a.m. or approximately 2 hours before sunrise near the start of morning twilight. Comet positions are shown every 3 days; stars plotted to about 7th magnitude. Lemmon travels from Pegasus into Andromeda over the next month. Credit: created with Chris Marriott’s SkyMap software

Comet C/2012 F6 Lemmon has finally risen high enough before dawn to clear the horizon haze and treeline. At 7th magnitude, you can see in binoculars a more compact fuzzy spot than PANSTARRS; a telescope will show a faint, short tail to the southwest. Time exposure photos reveal a soft, rounded dust tail and long, skinny gas or ion tail.

Watch as Venus, Jupiter and Mercury align after sunset

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The sky facing northwest this evening about 30-35 minutes after sundown. Venus and Jupiter should be relatively easy to spot provided you have an unobstructed view; Mercury might require binoculars. Stellarium

Hey, hey, hey. Three planets are now lining up in a neat row at dusk. Watch for the trio starting 30-35 minutes after sunset when they’ll be low in the northwestern sky.

The distance between Venus and Jupiter has shrunk over the past week and now stands at about 8 degrees or just shy of a fist held at arm’s length against the sky. Mercury finally joins the crew after emerging from the sun’s glare, though it will be the most challenging to see because of low elevation. As always when hunting planets in twilight, be a slacker and bring binoculars to make the job easy. Mercury will become easier to see by mid-week as it races up from the sun.

All three twilight planets appear close together near the sun in evening twilight is because they all lie in nearly the same line of sight (arrow) as seen from Earth. This view is a frame from a live orrery – click to watch the planets orbit the sun. Credit: dd.dynamicdiagrams.com

Venus is brightest at magnitude -3.4, while Jupiter and Mercury are near equals at -1.5 and -1.3 respectively. A week from now the three will all be clustered within a couple degrees of each other and form striking, triangle-shaped configurations that change night by night. I’ll have maps and times to look later this week. Get your cameras ready!

1998 QE2 asteroid flyby an opportunity for pros and amateurs alike

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Many separate telescopic images were combined to create this animation of asteroid 1998 QE2 moving through a star field this past week. Credit: Ernesto Guido and Nick Howes

An asteroid it would take an hour to walk across will speed past Earth on May 31 and provide radio astronomers a perfect opportunity to nab closeup views of its surface. 1998 QE2, discovered in 1998 by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program,  will miss our planet by a healthy 3.6 million miles (5.8 million km) or 15 times the distance of the moon. Closest approach occurs at 3:59 p.m. Central time.

The asteroid’s large size combined with its relatively close approach makes it a great target for both the 230-foot (70-m) Goldstone radio dish and 1,000-foot (305-m) Arecibo dish in Puerto Rico. Lance Benner, the principal investigator for the Goldstone radar observations from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., will have all hands on deck for the flyby. By sending bursts of radio waves at 1998 QE2 and measuring the retured radar echoes, Benner expects the dishes to resolve surface features as small as 12 feet (3.75m) across on the 1.7-mile-long asteroid (2.7 km).

The orbit of asteroid 1998 QE2. Its May 31 flyby will be the closest it comes to Earth for at least the next 200 years. Its closest point to the sun is similar to Earth’s; when farthest it’s 353 million miles from the sun in the asteroid belt between Mars and Jupiter. Credit: NASA/JPL-Caltech

Through an ordinary optical telescope, even a large one, 1998 QE2 will appear as a point of light. Radar observations reveal far more including shape, size, rotation and a wide variety of surface features. Goldstone observations are scheduled from May 30 – June 9; those at Arecibo for several days around June 5.

Already optical telescopes in the southern hemisphere have this monster rock in their crosshairs. By measuring repeating highs and lows in the asteroid’s brightness as it spins on its axis, astronomers can determine its rotation rate. 1998 QE2′s composition is gleaned by how it reflects sunlight. Reflected sunbeams streaming back to Earth carry the imprint of particular minerals that absorb and reflect portions of the sun’s light in unique ways that nail down their identities.

“It is tremendously exciting to see detailed images of this asteroid for the first time,” said Benner. “With radar we can transform an object from a point of light into a small world with its own unique set of characteristics. In a real sense, radar imaging of near-Earth asteroids is a fundamental form of exploring a whole class of solar system objects.”

1998 QE2 looks like a point of light in this time exposure taken remotely with a telescope in Australia by the team of Ernesto Guido and Nick Howes. The asteroid is currently very faint and only visible in the southern hemisphere. Click for more on the asteroid in their blog.

I’m excited about the asteroid because it will be bright enough to be visible in small telescopes across both northern and southern hemispheres for several nights around the time of closest approach. Between May 30 and June 5 it will shine at 10.5-11.0 magnitude while chugging through the constellations Libra and Ophiuchus, both conveniently placed at nightfall. Its steady movement across the sky – 2/3 of a full moon diameter an hour – will be obvious through the telescope. Come the end of the month, I’ll create a map to help you find it.

Read more about 1998 QE2 HERE. Amateur astronomers needing orbital elements and ephemerides can check out the Goldstone planner.

Aurora alert tonight May 17-18, 2013

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This map created with satellite data for 11:30 p.m. CDT May 17 shows the extent of the northern auroral oval, one of two permanent caps of aurora centered on Earth’s north and south geomagnetic poles. Normally the oval is small and snugged up over Hudson Bay. Tonight it’s expanded southward and could produce auroras across the northern border of the U.S. Click to see current oval. Credit: NOAA

If it were clear here in Duluth, I’m sure we’d be seeing northern lights. The Kp index, an indicator of magnetic activity around the Earth, shot up to “5″ or minor storm level around 11 p.m. Central time this evening (Friday). From the satellite plot, it appears the auroral oval extends across southern Canada almost to the U.S. border.

Since the aurora is quite high – around 60-200 miles – it’s visible a fair distance to the south of that line. In other words, northern parts of Minnesota, Michigan, Wisconsin, N. Dakota, Montana and Washington may get treated to the sight of northern lights overnight.

Sunspot region 1748 still has the potential for more solar storms. Since the group’s now becoming more face-on to Earth, additional flares could send CMEs in our direction. Another flare on May 17 sent material expected to arrive on the 19th. Credit: NASA

Be sure to take a look at the northern sky tonight for arcs and rays of aurora. As you might guess, the cause for this show lies with the recent X-class flares sunspot region 1748 has been pounding out over the week. Our planet was expected to get a glancing brush from a coronal mass ejection (CME) overnight from one of the recent blasts. Let us know if you see anything. And get ready for May 19 – Sunday – when another blast could spark an even more auroras.