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A jewel of the southern sky, the Great Carina Nebula, aka NGC 3372, spans over 300 light-years.

Near the upper right of this expansive skyscape, it is much larger than the more northerly Orion Nebula. In fact, the Carina Nebula is one of our galaxy’s largest star-forming regions and home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun.

Nebulae near the center of the 10 degree wide field include NGC 3576 and NGC 3603. Near center at the top of the frame is open star cluster NGC 3532, the Wishing Well Cluster.

More compact, NGC 3766, the Pearl Cluster, can be spotted at the left. Anchoring the lower left of the cosmic canvas is another large star-forming region, IC 2948 with embedded star cluster IC 2944. That region is popularly known as the Running Chicken Nebula.

Link to article: Chasing Carina

Put a satellite in a circular orbit about 42,000 kilometres from the center of the Earth (36,000 kilometres or so above the surface) and it will orbit once in 24 hours. Because that matches Earth’s rotation period, it is known as a geosynchronous orbit. If that orbit is also in the plane of the equator, the satellite will hang in the sky over a fixed location in a geostationary orbit.

As predicted in the 1940s by futurist Arthur C. Clarke, geostationary orbits are in common use for communication and weather satellites, a scenario now well-known to astroimagers.

Deep images of the night sky made with telescopes that follow the stars can also pick up geostationary satellites glinting in sunlight still shining far above the Earth’s surface. Because they all move with the Earth’s rotation against the background of stars, the satellites leave trails that seem to follow a highway across the celestial landscape.

For example, in this wide view of the nearly equatorial Orion region, individual frames were added to create a 10 minute long exposure. It shows Orion’s belt stars and well-known nebulae along with many 2.5 degree long geostationary satellite trails.

The frames are from an ingenious movie, featuring the geostationary satellite highway.

Link to article: Geostationary Highway

The snow capped Teide volcano is reflected in a pool of water in this nearly symmetric night sky view from the Canary Island Tenerife.

Bright north star Polaris stands above the peak in an exposure that also captures the brilliant trail of a polar orbiting Iridium satellite.

Of course, with the camera fixed to a tripod, the stars themselves produce concentric trails in long exposures, a reflection of the Earth’s rotation around its axis.

Large astronomical observatories also take advantage of the calm Canary Island sky.

Link to article: Teide Sky Trails

Astronomers presenting at the American Astronomical Society (AAS) meeting in Washington D.C. on Jan. 4, have reported the detection of the emission generated by a black hole as it devoured a white dwarf star in the elliptical galaxy NGC 1399.

This may not appear to be a huge deal to begin with — stars being eaten by supermassive black holes in the centers of galaxies have been detected before — but it would appear that this particular white dwarf was ripped apart and then devoured by a mysterious “intermediate-mass” black hole.

Black holes are thought to come in all sizes and astronomers are very familiar with stellar-mass black holes (i.e. black holes that are created from single massive star supernovae) and supermassive black hole behemoths (weighing in at several million solar masses) confirmed to be living in the centers of most galaxies.

But what about the black holes in between?

Black holes measuring in the range of hundreds to thousands of solar masses have only existed in theory up till now and observational evidence of these “medium-sized” singularities has been very hard to come by. However, the NGC 1399 observation may shed some light on the existence of a particular intermediate-mass black hole in the Fornax cluster, 65 million light years from Earth.

“Astronomers have made cases for stars being torn apart by supermassive black holes in the centers of galaxies before, but this is the first good evidence for such an event in a globular cluster,” said Jimmy Irwin of the University of Alabama who led the study.

Using X-ray data from NASA’s Chandra space telescope and optical data from the Magellan I and II telescopes in Las Campanas, Chile, Irwin and his colleagues were able to study an abnormally bright X-ray emission in the globular cluster.

This is known as an “ultraluminous X-ray source” (or ULX for short). By analyzing the ULX, the team was able to work out that a white dwarf had been shredded by the extreme tidal forces of a black hole and the material was being eaten by the black hole.

The observations suggest oxygen is in abundance, but there is a deficiency in hydrogen, suggesting that the material was being stripped from an old, white dwarf star. (The lack of hydrogen shows that the stellar object has burnt up its fuel, indicating the butchered star did not belong in the Main Sequence.)

Nitrogen was also detected in the spectrum, a factor that has yet to be explained.

By studying the characteristics of the material as it orbited and fell into the black hole — generating the X-rays as it was accelerated into the event horizon — the researchers were also able to deduce the black hole’s mass: approximately 1,000 suns, a mass that corresponds to a black hole in “Medium.”

Is this definitive proof of the existence of an intermediate-mass black hole killing a careless white dwarf star? Possibly, but further examination of the ULX will no doubt be forthcoming as it is thought that the X-ray emission from NGC 1399 should be persistent for some time yet.

Link to article: Intermediate black-hole implicated in star’s death

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An asterism is just a recognized pattern of stars that is not one the 88 official constellations. For example, one of the most famous (and largest) asterisms is the Big Dipper within the constellation Ursa Major. But this pretty chain of stars, visible with binoculars towards the long-necked constellation of Camelopardalis, is also a recognized asterism. Known as Kemble’s Cascade, it contains about 20 stars nearly in a row, stretching over five times the width of a full moon.

Tumbling from the upper right to lower left in the picture, Kemble’s Cascade was made popular by astronomy enthusiast Lucian Kemble. The bright object at the lower left is the relatively compact open cluster of stars, NGC 1502.

Link to article: Kemble’s Cascade

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Here are some vampires we don’t mind sparkling. This globular cluster, Messier 30, contains two types of ancient stars that have managed to keep themselves brilliant and young. One type relies on interstellar collisions; the other drinks from its neighbors.

Messier 30 is an unusual cluster. It’s an ancient cluster, and yet it is filled with blue stars, stars that tend to age and die more quickly than other types of stars. Astronomers have termed these unusually old blue stars “blue stragglers,” and they believe that there are two reasons these stars still exist.

Some of the blue stragglers in Messier 30 are vampires; when they get near a more massive star, they are able to siphon off hydrogen from that star, effectively lengthening its life. But more recent studies have found that some of the stars are the results of high-powered collisions. When two older stars collide head-on, it restokes their nuclear fusion, resulting in larger, seemingly younger blue stars than before.

Link to article: Vampirism and Collisions Keep Ancient Stars Young

Image by Nico Camargo and courtesy www.citizensky.org. Used under Creative Commons license.

Some kind of obstruction is blocking our view of Epsilon Aurigae, a star in the constellation Auriga. Its exact nature is unknown — but astronomers say that if you’ve got a telescope, you could help them figure it out.

Epsilon Aurigae is a binary system, or a star locked in a pattern of mutual orbit with a second body. It lies in the constellation Auriga, about two thousand light-years away from Earth. We like this star, because it gives us the chance to shout out to some old-school Green Day.

About every twenty-seven years, Epsilon Aurigae undergoes an eclipse that lasts between twenty and twenty-four Earth months. During this time, the light from the star dims appreciably. Astronomers aren’t sure what causes the eclipse; they believe it’s the companion body in the binary system, but there’s disagreement as to what exactly that body might be.

One popular school of thought is that the orbiting, eclipsing body is a huge disk of… something. Possibly dust and space debris, but really, no one is sure. Robert Stencel, a professor of astronomy at Denver University and longtime studier of Epsilon Aurigae, described the mystery object as “a dark disk of material” in a recent press release. “The exact shape and makeup of the disk has been unknown,” said Stencel, “but it will be better defined soon.”

“Soon,” because there’s another eclipse happening right now, and that affords us the chance to study the phenomenon again. This is where you and I come in, if we have any stargazing equipment. A project called Citizen Sky has put out an open call for amateur astronomers to watch Auriga and contribute information on the mysterious star-blocker. (Stencel is a team member of Citizen Sky, in addition to his professorial duties. He wears many hats, it seems.)

Epsilon Aurigae is so bright that it can be seen from just about anywhere on Earth, so if you’re of a mind, head over to the Citizen Sky site and see whether it looks interesting. If it turns out — and I’m just going to say what we’re all thinking here — if it turns out that the object orbiting Epsilon Aurigae is an alien mothership of some kind, and you’re the first to identify it as such, then there’s a decent chance you could get the thing named after yourself.

Link to article: There’s A “Dark Disk of Material” Hovering Out In Space

What would it look like to travel across the known universe? To help humanity visualize this, the American Museum of Natural History has produced a modern movie featuring many visual highlights of such a trip.

The video starts in Earth’s Himalayan Mountains and then dramatically zooms out, showing the orbits of Earth’s satellites, the Sun, the Solar System, the extent of humanities first radio signals, the Milky Way Galaxy, galaxies nearby, distant galaxies, and quasars. As the distant surface of the microwave background is finally reached, radiation is depicted that was emitted billions of light years away and less than one million years after the Big Bang.

Frequently using the Digital Universe Atlas, every object in the video has been rendered to scale given the best scientific research in 2009, when the video was produced. The film has similarities to the famous Powers of Ten video that has been a favorite of many space enthusiasts for a generation.

Link to article: The Known Universe

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Birds don’t fly this high. Airplanes don’t go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description.

Pictured above, the Space Shuttle Atlantis lifted off to visit the International Space Station during the early morning hours of 2001 July 12. From a standing start, the two million kilogram rocket ship left to circle the Earth where the outside air is too thin to breathe and where there is little noticeable onboard gravity. Rockets bound for space are now launched from somewhere on Earth about once a week.

Link to article: Atlantis to Orbit

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Beautiful island universe M94 lies a mere 15 million light-years distant in the northern constellation of the hunting dogs, Canes Venatici. A popular target for astronomers, the brighter inner part of the face-on spiral galaxy is about 30,000 light-years across.

Traditionally, deep images have been interpreted as showing M94′s inner spiral region surrounded by a faint, broad ring of stars. But a new multi-wavelength investigation has revealed previously undetected spiral arms sweeping across the outskirts of the galaxy’s disk, an outer disk actively engaged in star formation. At optical wavelengths, M94′s outer spiral arms are followed in this remarkable discovery image, processed to enhance the outer disk structure. Background galaxies are visible through the faint outer arms, while the three spiky foreground stars are in our own Milky Way galaxy.

Link to article: M94: A New Perspective