Artist's Concept of a Protostar within the Orion A Molecular Cloud

Orion A, a star-forming nebula lying about 1500 light-years from Earth, as viewed by ESA's Herschel space observatory. Orion A is located within the 'sword of Orion' – below the three main stars that form the belt of the Orion constellation.

Embedded in the gaseous and dusty environment of this molecular cloud is the prolific stellar nursery called OMC2 FIR4 (highlighted with a red circle).

Astronomers studying OMC2 FIR4 with Herschel have discovered that at least one of the embryo stars that are taking shape in this protostellar cocoon is gusting a powerful wind of very energetic particles.

The inset shows an illustration of the wind blown by this newborn star. When the energetic particles hit the surrounding material, they may collide with atoms that are present in the star's environment, break them apart and produce new elements.

Our Sun likely gusted a similar wind of particles in its early days; this could explain the origin of a puzzling isotope of beryllium, whose traces are found in meteorites.

Image credit: Herschel image: ESA/Herschel/Ph. André, D. Polychroni, A. Roy, V. Könyves, N. Schneider for the Gould Belt survey Key Programme; inset and layout: ESA/ATG medialab

Note: For more information, see Young Sun's Violent History Solves Meteorite Mystery.

Protostar RNO 91 in Nebula LDN 43

A very young star, RNO 91, is being born in the guts of the dark cloud LDN 43, 520 light-years from Earth in the constellation of Ophiuchus. The newborn star is hidden in this image, revealed only by light reflected onto the plumes of the dark cloud. A dusty, icy disc surrounding it may host planet embryos.

Photo credit: ESA/Hubble & NASA; Acknowledgement: J. Schmidt

Star Formation in the Orion Nebula

This new view of the Orion Nebula shows embryonic stars within extensive gas and dust clouds. Combining far-infrared observations from the Herschel Space Observatory and mid-infrared observations from NASA's Spitzer Space Telescope, the image shows newly forming stars surrounded by remnant gas and dust in the form of discs and larger envelopes.

Data from the PACS instrument on Herschel at wavelengths of 70 and 160 microns (a micron is a millionth of a meter) are shown as green and red, respectively, and reveal emission from the disks and envelopes of the very youngest protostars. Two Spitzer instruments, IRAC and MIPS, were used to obtain images of the same region at 8 and 24 microns, which are combined here as blue. These wavelengths show emission from the hotter regions of discs around somewhat older stars.

The region shown covers roughly 25x25 arcminutes on the sky or 3x3 parsecs at the distance to Orion.

Photo credits: ESA/PACS/NASA/JPL-Caltech/IRAM

Note: For more information, see Fledgling Stars Flicker in the Heart of Orion; also, Young Stars Flicker Amidst Clouds of Gas and Dust.

IC 4601 - Dusty Reflections in the Scorpion's Claws

Between the claws of the dreaded scorpion imagined by the ancient Greeks lies this giant dust cloud, imaged by the Wide-field Infrared Survey Explorer, or WISE. The constellation of Scorpius is prominent in the summer night sky in North America. In visible light, this cloud, or nebula, appears dark with a ghostly blue shine about it. These types of nebulae are called "reflection," because they are reflecting the light of nearby stars. The dust within the cloud reflects mostly blue light.

However, WISE sees infrared light invisible to the eye. In infrared light, we can see the dust itself glowing rather than simply reflecting light. The green and red colors in this image show dust at different temperatures, with the green dust being warmer than the red dust. The dust is warmed by the light of nearby stars. This interstellar dust contains the heavy elements that planets are made of, and plays a major role in the creation of new stars.

The nebula, known as IC 4601, is part of a larger complex of clouds where new stars are being born. Some of the red stars in this image may in fact be baby stars wrapped in blankets of dust. Perhaps the dreaded scorpion can be thought of as rocking the baby stars to sleep.

This image was made from observations by all four infrared detectors aboard WISE. Blue and cyan (blue-green) represent infrared light at wavelengths of 3.4 and 4.6 microns, which is primarily from stars, the hottest objects pictured. Green and red represent light at 12 and 22 microns, which is primarily from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA

NGC 281 - The Pacman Nebula in Infrared

In visible light, the star-forming cloud cataloged as NGC 281 in the constellation of Cassiopeia appears to be chomping through the cosmos, earning it the nickname the "Pacman" nebula after the famous Pac-Man video game of the 1980s. However, the Wide-field Infrared Survey Explorer, or WISE, observed the nebula in infrared light, revealing a different view.

NGC 281 is a giant cloud of dust and gas located about 9,200 light-years away within our own Milky Way galaxy, and spans about 130 light-years in space. Inside the cloud, a new cluster of stars is forming. This young cluster, called IC 1590, appears as a group of stars near the center of the red and green cloud in the upper portion of the image. Within the cluster there are several very massive stars, many times the mass of the sun. These stars are also very hot and produce large amounts of ultraviolet radiation and blow strong winds. The radiation and winds erode the larger cloud from the inside out, giving it a shell-like appearance. The winds and radiation heat the dust in the cloud, which then glows in infrared light. The wavelengths at which the dust glows depends on the temperatures.

The process of the erosion of the nebula by the young star cluster is thought to trigger the additional formation of stars. Around the edges of NGC 281 are many long columns pointing toward the central star cluster, giving the appearance of the Pacman with teeth. These are parts of the cloud that are a bit more dense, and hence erode more slowly than the rest of the cloud. At the tips of these columns, the material may be compressed enough to set off the formation of new stars. Also, sprinkled around the images are several star-like objects that appear very red. These are likely baby stars in the early stages of formation. They are wrapped in cocoons of dust, which glow strongly in the longer wavelengths, giving them their red color in this image.

This image was made from observations by all four infrared detectors aboard WISE. Blue and cyan (blue-green) represent infrared light at wavelengths of 3.4 and 4.6 microns, which is primarily from stars, the hottest objects pictured. Green and red represent light at 12 and 22 microns, which is primarily from warm dust (with the green dust being warmer than the red dust).

Photo credit: NASA/JPL-Caltech/UCLA

Star Formation in the Circinus Molecular Cloud Complex

The Wide-Field Infrared Survey Explorer, or WISE, has uncovered a striking population of young stellar objects in a complex of dense, dark clouds in the southern constellation of Circinus. This mosaic from WISE covers an area on the sky so large that it could contain a grid of 11 by 7 full moons. The cloud itself is some 2,280 light-years away and spans more than 180 light-years across.

When an interstellar cloud becomes dense and cool enough, molecules can form in it, so astronomers call these molecular clouds. Molecular clouds are where stars first form, and astronomers study them hoping to learn about the earliest stages in the lives of stars. These clouds are so dense that the dust within blocks visible wavelengths of light. Telescopes that see visible light only detect ghostly dark patches in the sky, called dark nebulae. The infrared vision of WISE was able to pierce through the cloud and see the light of the dust itself and newly forming stars within.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust.

In the western part of the cloud (right of the image center) there is a prominent cluster of red-colored sources. This is light coming from large amounts of warm, concentrated dust. These are what astronomers call young stellar objects, stars so new that they have yet to begin nuclear fusion in their cores and are enveloped by cocoons of dust. These young stars also power large-scale outflows of gas that are detected by radio telescopes. As these young stars develop, they will emerge from their cocoons and begin to light up their surroundings, making the Circinus cloud shine in visible light.

Also in this image: the brightest star in the upper-right is IRAS 14484-6152, a giant star rich in carbon. The red object to the east (left) of the brightest nebulosity is an O-type star. It derives its red color from the surrounding dust, which is being heated by this massive star.

Photo credit: NASA/JPL-Caltech/UCLA

Star IRAS 13481-6124 and Nebula

This star-forming region, captured by NASA's Spitzer Space Telescope, is dominated by the bright, young star IRAS 13481-6124 (upper left), which is about twenty times the mass of our sun and five times its radius, and is surrounded by its pre-natal cocoon. It is the first massive baby star for which astronomers could obtain a detailed look at the dusty disk closely encircling it. The research provides direct evidence that massive stars do form in the same way as their smaller brethren.

From this archival Spitzer image, as well as from observations done with the APEX 12-meter sub-millimeter telescope, astronomers discovered the presence of a jet, hinting at the presence of a disk. This was then confirmed by observations made with the European Southern Observatory Very Large Telescope Interferometer.

This picture was taken with Spitzer's infrared array camera. It is a four-color composite, in which light with a wavelength of 3.6 microns is blue; 4.5-micron light is green; 5.8-micron light is orange; and 8-micron light is red. Dust appears red-orange and most stars are blue, though ones deeply embedded within dust (like IRAS 13481-6124) take on greenish-yellow tints.

Photo credit: NASA/JPL-Caltech/ESO/Univ. of Michigan
Illustration credit: ESO/L. Calçada

Notes: For more information, see Unravelling the Mystery of Massive Star Birth. This star is located roughly 10,000 light-years away in the constellation of Centaurus.

SN 1572 - Tycho Brahe's Supernova

This image from NASA's Wide-field Infrared Survey Explorer (WISE) takes in several interesting objects in the constellation Cassiopeia, none of which are easily seen in visible light.

The red circle visible in the upper left part of the image is SN 1572, often called "Tycho's Supernova." This remnant of a star explosion is named after the astronomer Tycho Brahe, although he was not the only person to observe and record the supernova. When the supernova first appeared in November 1572, it was as bright as Venus and could be seen in the daytime. Over the next two years, the supernova dimmed until it could no longer be seen with the naked eye. It wasn't until the 1950s that the remnants of the supernova could be seen again with the help of telescopes.

When the star exploded, it sent out a blast wave into the surrounding material, scooping up interstellar dust and gas as it went, like a snow plow. An expanding shock wave traveled into the surroundings and a reverse shock was driven back in toward the remnants of the star. Previous observations by NASA's Spitzer Space Telescope indicate that the nature of the light that WISE sees from the supernova remnant is emission from dust heated by the shock wave.

In the center of the image is a star-forming nebula of dust and gas, called S175. This cloud of material is about 3,500 light-years away and 35 light-years across. It is being heated by radiation from young, hot stars within it, and the dust within the cloud radiates infrared light.

On the left edge of the image, between the Tycho supernova remnant and the very bright star, is an open cluster of stars, King 1, first cataloged by Ivan King, an astronomer at UC Berkeley, California. [Dr. King was at Cal when he discovered King 1; he now teaches at the University of Washington.] This cluster is about 6,000 light-years away, 4 light-years across and is about 2 billion years old.

Also of interest in the lower right of the image is a cluster of infrared-emitting objects. Almost all of these sources have no counterparts in visible-light images, and only some have been cataloged by previous infrared surveys. There are indications that they may be young stellar objects associated with a dense nebula in the area. Young stellar objects (YSOs) are stars in their earliest stages of life. YSOs are surrounded by an envelope of dust, which would explain the very red color of the sources in this image.

All four infrared detectors aboard WISE were used to make this mosaic. The image spans an area of 1.6 x 1.6 degrees on the sky or about 3 times as wide and high as the full moon. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Photo credit: NASA/JPL-Caltech/UCLA

Protostellar Envelopes and Jets

New evidence from NASA's Spitzer Space Telescope is showing that tight-knit twin stars might be triggered to form by asymmetrical envelopes like the ones shown in this image. All stars, even single ones like our sun, are known to form from collapsing clumps of gas and dust, called envelopes, which are seen here around six forming star systems as dark blobs, or shadows, against a dusty background. The greenish color shows jets coming away from the envelopes. The envelopes are all roughly 100 times the size of our solar system.

Two of the six envelopes are known to have already formed twin, or binary stars (Spitzer can see the envelopes but not the stars themselves). Astronomers believe that the irregular shapes of these envelopes, revealed in detail by Spitzer, might trigger binary stars to form, or might have already triggered them to form.

From top left, moving clockwise, the stars are: IRAS 03282+3035, CB230, IRAS 16253-2429, L1152, L483, HH270 VLA1. IRAS 03282+3035 and CB230 are the two known to have already formed binary stars.

Infrared light with a wavelength of 3.6 microns has been color-coded blue; 4.5-micron light is green; and 8.0-micron light is red.

Photo credit: NASA/JPL-Caltech/Univ. of Michigan