Feast your Eyes on the Fried Egg Nebula
Astronomers have used ESO’s Very Large Telescope to image a colossal star that belongs to one of the rarest classes of stars in the Universe, the yellow hypergiants. The new picture is the best ever taken of a star in this class and shows for the first time a huge dusty double shell surrounding the central hypergiant. The star and its shells resemble an egg white around a yolky centre, leading the astronomers to nickname the object the Fried Egg Nebula.
The monster star, known to astronomers as IRAS 17163-3907, has a diameter about a thousand times bigger than our Sun. At a distance of about 13,000 light-years from Earth, it is the closest yellow hypergiant found to date and new observations show it shines some 500,000 times more brightly than the Sun.
If the Fried Egg Nebula were placed in the centre of the Solar System the Earth would lie deep within the star itself and the planet Jupiter would be orbiting just above its surface. The much larger surrounding nebula would engulf all the planets and dwarf planets and even some of the comets that orbit far beyond the orbit of Neptune. The outer shell has a radius of 10,000 times the distance from the Earth to the Sun.
Yellow hypergiants are in an extremely active phase of their evolution, undergoing a series of explosive events — this star has ejected four times the mass of the Sun in just a few hundred years. The material flung out during these bursts has formed the extensive double shell of the nebula, which is made of dust rich in silicates and mixed with gas.
This activity also shows that the star is likely to soon die an explosive death — it will be one of the next supernova explosions in our galaxy.
Asteroid caught marching across Tadpole Nebula
This infrared image from the WISE telescope showcases the Tadpole Nebula, a star-forming hub in the Auriga constellation about 12,000 light-years from Earth. As WISE scanned the sky it happened to catch an asteroid in our solar system passing by. The asteroid, called 1719 Jens, left tracks across the image. A second asteroid was also observed cruising by.
But that’s not all that WISE caught in this busy image — two natural satellites orbiting above WISE streak through the image, appearing as faint green trails. This Tadpole region is chock full of stars as young as only a million years old and masses over 10 times that of our sun.
It is called the Tadpole nebula because the masses of hot, young stars are blasting out ultraviolet radiation that has etched the gas into two tadpole-shaped pillars, called Sim 129 and Sim 130. These “tadpoles” appear as the yellow squiggles near the center of the frame. The knotted regions at their heads are likely to contain new young stars.
The Pencil Nebula Supernova Shockwave
At 500,000 kilometers per hour, a supernova shockwave plows through interstellar space. This shockwave is known as the Pencil Nebula, or NGC 2736, and is part of the Vela supernova remnant, an expanding shell of a star that exploded about 11,000 years ago.
Initially the shockwave was moving at millions of kilometers per hour, but the weight of all the gas it has swept up has slowed it considerably. Pictured above, the shockwave moves from left to right, as can be discerned by the lack of gas on the left. The above region spans nearly a light year across, a small part of the 100+ light-year span of the entire Vela supernova remnant.
An Angry Bird in the Sky
A new image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope reveals the Lambda Centauri Nebula, a cloud of glowing hydrogen and newborn stars in the constellation of Centaurus. The nebula, also known as IC 2944, is sometimes nicknamed the Running Chicken Nebula, from a bird-like shape some people see in its brightest region, though there is some disagreement over exactly which part of the nebula is chicken shaped, with various bird-like features in evidence across the picture.
In the nebula, which lies around 6500 light-years from Earth, hot newborn stars that formed from clouds of hydrogen gas shine brightly with ultraviolet light. This intense radiation in turn excites the surrounding hydrogen cloud, making it glow a distinctive shade of red, typical of star-forming regions.
The series of opaque black clumps silhouetted against the red background are examples of a type of object called Bok globules. They appear dark as they absorb the light from the luminous background. However, observations of these dark clouds using infrared telescopes have revealed that stars are forming within many of them.
These glowing nebulae are relatively short-lived in astronomical terms (typically a few million years), meaning that the Lambda Centauri Nebula will eventually fade away as it loses both its gas and its supply of ultraviolet radiation.
Vela Supernova Remnant
The Vela supernova remnant is a supernova remnant in the southern constellation Vela, one of the closest known to us. Its source supernova exploded approximately 11,000-12,300 years ago (and was about 800 light years away).
The Vela supernova remnant includes NGC 2736. It also overlaps the Puppis Supernova Remnant, which is four times more distant. Both the Puppis and Vela remnants are among the largest and brightest features in the x-ray sky.
Fighting Dragons of Ara (NGC 6188 & 6164)
NGC 6188 is an emission nebula located about 4,000 light years away in the constellation Ara. The bright open cluster NGC 6193, visible to the naked eye, is responsible for a region of reflection nebulosity within NGC 6188.
Into the Depths of the Lagoon Nebula
Swirling dust clouds and bright newborn stars dominate the view in this image of the Lagoon nebula from NASA’s Spitzer Space Telescope. Also known as Messier 8 and NGC 6523, astronomers estimate it to be between 4000 and 6000 light years away, lying in the general direction of the center of our galaxy in the constellation Sagittarius.
The glowing waters of the Lagoon, as seen in visible light, are really pools of hot gas surrounding the massive, young stars found here. Spitzers infrared vision looks past the gas to show the dusty basin that it fills. Here we see the central regions of the Lagoon with green showing the glow of carbon-based dust grains, and red highlighting the thermal glow of the hottest dust.
The various columns of dust all seem to point inwards towards the central depths of the Lagoon. These structures are being sculpted by the intense glow of giant, young stars found at the nebulas core. Within these clouds of dust and gas, a new generation of stars is forming.
The Elephant Trunk Nebula
Resembling a creature on the run with flames streaming behind it, the Elephant Trunk Nebula is one of few large nebulas that can be seen with the naked eye, although only under extremely dark skies. The nebula is located in the constellation of Cepheus, approximately 2,400 light years away.
This image was taken by Bob and Janice Fera taken between July 23-26, 2011 from Eagle Ridge Observatory, Foresthill, CA.
The elephant trunk nebula is an emission nebula, which means it has a cloud of ionized gas emitting light of various colors, typically through high-energy photons. Scientists believe the nebula could be a site for star formation with young stars emerging from a small cavity in the head of the globule.
A Starfish in the Sky
In the Aquila constellation lies a star nearing the end of its life that is surrounded by a starfish-shaped cloud of gas and dust. A striking image of this object, known as IRAS 19024+0044 has been captured by the Hubble Space Telescope. Protoplanetary nebulae offer glimpses of how stars similar to the Sun end their lives and how they make the transition to white dwarfs surrounded by planetary nebulae.
Clearly visible in this image are five blue lobes that extend away from the central star and give the nebula its asymmetric starfish shape. While astronomers have come up with theories for the origin of these structures, such as direction-changing jets or explosive ejections of matter from the star, their formation is not entirely understood.
The Beauty of Asymmetry
Planetary nebulae signal the demise of mid-sized stars (up to about eight times the mass of the Sun); when the star’s hydrogen fuel supply is exhausted, its outer layers expand and cool, creating a cocoon of gas and dust. This gas then glows as it is bathed in the strong ultraviolet radiation from the central star. NGC 5882 is a quite bright, but small, example of a planetary nebula that lies deep in the southern Milky Way in the constellation of Lupus.
Planetary nebulae sometimes have a perfectly symmetrical appearance, with gas being bellowed out from the dying star evenly in every direction. However, this isn’t the case for NGC 5882. It appears to have two distinct, but non-uniform regions: an elongated inner shell of gas and a fainter aspherical shell that surrounds it.
Hubble’s sharp view reveals the intricate knots, filaments and bubbles within these shells. But it’s the dying star at the heart of the planetary nebula that dominates the image, shining brightly with an incredible surface temperature of about 70,000 °Celsius. (For comparison, the surface temperature of the Sun is only about 5500 °Celsius.) The high surface temperature of this white dwarf is a result of the star’s struggle for survival, finding new ways to prevent itself from collapsing under its own gravity.
A rich collection of colorful astronomical objects is revealed in this picturesque image of the Rho Ophiuchi cloud complex, which is found rising above the plane of the Milky Way in the night sky, bordering the constellations Ophiuchus and Scorpius. It’s one of the nearest star-forming regions to Earth.
The amazing variety of different colors seen in this image represents different wavelengths of infrared light. The bright white nebula in the center of the image is glowing due to heating from nearby stars, resulting in what is called an emission nebula. The same is true for most of the multi-hued gas prevalent throughout the entire image, including the bluish bow-shaped feature near the bottom right. The bright red area in the bottom right is light from the star in the center – Sigma Scorpii – that is reflected off of the dust surrounding it, creating what is called a reflection nebula. And the much darker areas scattered throughout the image are pockets of cool dense gas that block out the background light, resulting in absorption (or ‘dark’) nebulae.
The bright pink objects just left of center are baby stars just now forming; many of them are still enveloped in their own tiny compact nebulae. Some of the oldest stars in our Milky Way Galaxy are also visible in this image, found in two separate (and much more distant) globular clusters: M80 at the far right edge of the image towards the top, and NGC 6144, close to the bottom edge near the center.
The Rose-red Glow of Star Formation
The vivid red cloud in this new image from ESO’s Very Large Telescope is a region of ionised hydrogen surrounding the star cluster NGC 371. This stellar nursery lies in our neighbouring galaxy, the Small Magellanic Cloud.
NGC 371 is a HII region; it is an open cluster surrounded by a nebula. The stars in open clusters all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation, leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars. These energetic youngsters emit copious amounts of ultraviolet radiation causing surrounding gas to light up with a colourful glow that extends for hundreds of light-years in every direction.
NGC 371 is of particular interest due to the unexpectedly large number of variable stars it contains. These are stars that change in brightness over time. A particularly interesting type of variable star, known as slowly pulsating B stars, can also be used to study the interior of stars through asteroseismology, and several of these have been confirmed in this cluster. Variable stars play a pivotal role in astronomy: some types are invaluable for determining distances to far-off galaxies and the age of the Universe.
This swirling landscape of stars is known as the North America Nebula. In visible light, the region resembles North America, but in this new infrared view from NASA’s Spitzer Space Telescope, the continent disappears.
The reason you don’t see it in Spitzer’s view is due, in part, to the fact that infrared light can penetrate dust whereas visible light cannot. Dusty, dark clouds in the visible image become transparent in Spitzer’s view. In addition, Spitzer’s infrared detectors pick up the glow of dusty cocoons enveloping baby stars.
Clusters of young stars (about one million years old) can be found throughout the image. Slightly older but still very young stars (about 3-5 million years) are also liberally scattered across the complex. Some areas of this nebula are still very thick with dust and appear dark even in Spitzer’s view and are likely to be the youngest stars in the complex (less than a million years old).
A Celestial Shamrock
This infrared image from NASA’s WISE telescope features a region of star birth wrapped in a blanket of green colored dust. Designated as LBN 149.02-00.13, this interstellar cloud of dust and gas is a classic example of what astronomers call an HII region, because of all the ionized hydrogen within it. Ionized gases carry an electric charge.
This stellar nursery is made up of a shell of ionized gas surrounding a void with an extremely hot, bright star in the middle. With strong stellar winds and intense ultraviolet radiation, the central star — CY Camelopardalis — both clears away nearby gas and dust and heats the remaining dust in the shell, causing it to glow in infrared.
The green dust in the surrounding shell is mostly made of polycyclic aromatic hydrocarbon grains, similar to soot. They are warmer in temperature than the more metallic dust grains seen glowing in red around CY Cam. The heavy elements in such dust particles are cooked up in previous generations of stars and then incorporated into the new stars that are born from the cloud. This really is a region of rebirth and life.
LBN 149.02-00.13 can be found along the band of the Milky Way in the night sky, where clouds of gas and dust are much more common. It is located on the outer edge of our local spiral arm (the Orion Arm) about 3,000 light years away.
Small clusters of bright red objects are seen near the upper left of the image. These are likely Young Stellar Objects, surrounded by cocoons of dense dust. The clouds of gas and dust surrounding each star provide the material from which future planets might possibly form. Perhaps we are seeing the birth of several new planetary systems in this one image alone.
The Drama of Starbirth
The star-forming region NGC 6729 is part of one of the closest stellar nurseries to the Earth and hence one of the best studied. This new image from ESO’s Very Large Telescope gives a close-up view of a section of this strange and fascinating region [View wide-field image].
Stars form deep within molecular clouds and the earliest stages of their development cannot be seen in visible-light telescopes because of obscuration by dust. In this image there are very young stars at the upper left of the picture. Although they cannot be seen directly, the havoc that they have wreaked on their surroundings dominates the picture.
High-speed jets of material that travel away from the baby stars at velocities as high as one million kilometres per hour are slamming into the surrounding gas and creating shock waves. These shocks cause the gas to shine and create the strangely coloured glowing arcs and blobs known as Herbig–Haro objects.