The Nebula Beginning

1. The Nebula Beginning

2. The Nebula Beginning

3. The Nebula Beginning M17

4. The Nebula Beginning M1 – The Orion Nebula

5. The Nebula Beginning OXYGEN-RICH SUPERNOVA REMNANT IN THE LARGE MAGELLANIC CLOUD This is a NASA Hubble Space Telescope image of the tattered debris of a star that exploded 3,000 years ago as a supernova. This supernova remnant, called N132D, lies 169,000 light-years away in the satellite galaxy, the Large Magellanic Cloud. A Hubble Wide Field Planetary Camera 2 image of the inner regions of the supernova remnant shows the complex collisions that take place as fast moving ejecta slam into cool, dense interstellar clouds. This level of detail in the expanding filaments could only be seen previously in much closer supernova remnants. Now, Hubble's capabilities extend the detailed study of supernovae out to the distance of a neighboring galaxy. Material thrown out from the interior of the exploded star at velocities of more than four million miles per hour (2,000 kilometers per second) plows into neighboring clouds to create luminescent shock fronts. The blue-green filaments in the image correspond to oxygen-rich gas ejected from the core of the star. The oxygen-rich filaments glow as they pass through a network of shock fronts reflected off dense interstellar clouds that surrounded the exploded star. These dense clouds, which appear as reddish filaments, also glow as the shock wave from the supernova crushes and heats the clouds. Supernova remnants provide a rare opportunity to observe directly the interiors of stars far more massive than our Sun. The precursor star to this remnant, which was located slightly below and left of center in the image, is estimated to have been 25 times the mass of our Sun. These stars "cook" heavier elements through nuclear fusion, including oxygen, nitrogen, carbon, iron etc., and the titanic supernova explosions scatter this material back into space where it is used to create new generations of stars. This is the mechanism by which the gas and dust that formed our solar system became enriched with the elements that sustain life on this planet. Hubble spectroscopic observations will be used to determine the exact chemical composition of this nuclear- processed material, and thereby test theories of stellar evolution. The image shows a region of the remnant 50 light-years across. The supernova explosion should have been visible from Earth's southern hemisphere around 1,000 B.C., but there are no known historical records that chronicle what would have appeared as a "new star" in the heavens. This "true color" picture was made by superposing images taken on 9-10 August 1994 in three of the strongest optical emission lines: singly ionized sulfur (red), doubly ionized oxygen (green), and singly ionized oxygen (blue). Photo credit: Jon A. Morse (STScI) and NASA

6. The Nebula Beginning STELLAR "EGGS" EMERGE FROM MOLECULAR CLOUD (Star-Birth Clouds in M16) This eerie, dark structure, resembling an imaginary sea serpent's head, is a column of cool molecular hydrogen gas (two atoms of hydrogen in each molecule) and dust that is an incubator for new stars. The stars are embedded inside finger-like protrusions extending from the top of the nebula. Each "fingertip" is somewhat larger than our own solar system. The pillar is slowly eroding away by the ultraviolet light from nearby hot stars, a process called "photoevaporation". As it does, small globules of especially dense gas buried within the cloud is uncovered. These globules have been dubbed "EGGs" -- an acronym for "Evaporating Gaseous Globules". The shadows of the EGGs protect gas behind them, resulting in the finger-like structures at the top of the cloud. Forming inside at least some of the EGGs are embryonic stars -- stars that abruptly stop growing when the EGGs are uncovered and they are separated from the larger reservoir of gas from which they were drawing mass. Eventually the stars emerge, as the EGGs themselves succumb to photoevaporation. The stellar EGGS are found, appropriately enough, in the "Eagle Nebula" (also called M16 -- the 16th object in Charles Messier's 18th century catalog of "fuzzy" permanent objects in the sky), a nearby star-forming region 7,000 light-years away in the constellation Serpens. The picture was taken on April 1, 1995 with the Hubble Space Telescope Wide Field and Planetary Camera 2. The color image is constructed from three separate images taken in the light of emission from different types of atoms. Red shows emission from singly-ionized sulfur atoms. Green shows emission from hydrogen. Blue shows light emitted by doubly- ionized oxygen atoms. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

7. The Nebula Beginning GIANT STARBIRTH REGION IN NEIGHBORING GALAXY This is a Hubble Space Telescope image (right) of a vast nebula called NGC 604, which lies in the neighboring spiral galaxy M33, located 2.7 million light-years away in the constellation Triangulum. This is a site where new stars are being born in a spiral arm of the galaxy. Though such nebulae are common in galaxies, this one is particularly large, nearly 1,500 light-years across. The nebula is so vast it is easily seen in ground-based telescopic images (left). At the heart of NGC 604 are over 200 hot stars, much more massive than our Sun (15 to 60 solar masses). They heat the gaseous walls of the nebula making the gas flouresce. Their light also highlights the nebula's three-dimensional shape, like a lantern in a cavern. By studying the physical structure of a giant nebula, astronomers may determine how clusters of massive stars affect the evolution of the interstellar medium of the galaxy. The nebula also yields clues to its star formation history and will improve understanding of the starburst process when a galaxy undergoes a "firestorm" of star formation. The image was taken on January 17, 1995 with Hubble's Wide Field and Planetary Camera 2. Separate exposures were taken in different colors of light to study the physical properties of the hot gas (17,000 degrees Fahrenheit, 10,000 degrees Kelvin). Credit: Hui Yang (University of Illinois), Jeff J. Hester (University of Arizona) and NASA.

8. The Nebula Beginning HUBBLE SNAPS "FAMILY PORTRAIT" The Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has peered into the Cone Nebula, revealing a stunning image of six baby sun-like stars surrounding their mother, a bright, massive star. Known as NGC 2264 IRS, the massive star triggered the creation of these baby stars by releasing high-speed particles of dust and gas during its formative years. The image on the left, taken in visible light by a ground-based telescope, shows the Cone Nebula, located 2,500 light-years away in the constellation Monoceros. The white box pinpoints the location of the star nursery. The nursery cannot be seen in this image because dust and gas obscure it. The large cone of cold molecular hydrogen and dust rising from the lefthand edge of the image was created by the outflow from NGC 2264 IRS. The NICMOS image on the right shows this massive star - the brightest source in the region - and the stars formed by its outflow. The baby stars are only .04 to .08 light-years away from their brilliant mother. The rings surrounding the massive star and the spikes emanating from it are not part of the image. This pattern demonstrates the near-perfect optical performance of NICMOS. A near-perfect optical system should bend light from point-like sources, such as NGC 2264 IRS, forming these diffraction patterns of rings and spikes. This false color image was taken with 1.1-, 1.6-, and 2.2-micron filters. The image was taken on April 28, 1997. Credits: Rodger Thompson, Marcia Rieke and Glenn Schneider (University of Arizona), and NASA

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10. The Nebula Beginning Ghostly Reflections in the Pleiades STScI-PRC2000-36 NASA's Hubble Space Telescope has caught the eerie, wispy tendrils of a dark interstellar cloud being destroyed by the passage of one of the brightest stars in the Pleiades star cluster. Like a flashlight beam shining off the wall of a cave, the star is reflecting light off the surface of pitch black clouds of cold gas laced with dust. These are called reflection nebulae.

11. The Nebula Beginning EDGE-ON PROTOPLANETARY DISK IN THE ORION NEBULA Resembling an interstellar Frisbee, this is a disk of dust seen edge-on around a newborn star in the Orion nebula, located 1,500 light-years away. Because the disk is edge-on, the star is largely hidden inside, in this striking Hubble Space Telescope picture. The disk may be an embryonic planetary system in the making. Our solar system probably formed out of just such a disk 4.5 billion years ago. At 17 times the diameter of our own solar system, this disk is the largest of several recently discovered in the Orion nebula. The left image is a three-color composite, taken in blue, green, and red emission lines from glowing gas in the nebula. The right image was taken through a different filter, which blocks any bright spectral emission lines from the nebula, and hence the disk itself is less distinctly silhouetted against the background. However, clearly visible in this image are nebulosities above and below the plane of the disk; these betray the presence of the otherwise invisible central star, which cannot be seen directly due to dust in the edge-on disk. The images were taken between January 1994 and March 1995, and a study of their characteristics has been submitted for publication to the Astronomical Journal. Credit: Mark McCaughrean (Max-Planck-Institute for Astronomy), C. Robert O'Dell (Rice University), and NASA

12. The Nebula Beginning CLOSE-UP OF "PROPLYDS" IN ORION A Hubble Space Telescope view of a small portion of the Orion Nebula reveals five young stars. Four of the stars are surrounded by gas and dust trapped as the stars formed, but were left in orbit about the star. These are possibly protoplanetary disks, or "proplyds," that might evolve on to agglomerate planets. The proplyds which are closest to the hottest stars of the parent star cluster are seen as bright objects, while the object farthest from the hottest stars is seen as a dark object. The field of view is only 0.14 light-years across. The Orion Nebula star-birth region is 1,500 light-years away, in the direction of the constellation Orion the Hunter. The image was taken on 29 December 1993 with the HST's Wide Field and Planetary Camera 2. credit: C.R. O'Dell/Rice University NASA

13. The Nebula Beginning WARPED DISK MAY INDICATE PRESENCE OF PLANET AROUND THE STAR BETA PICTORIS This image from NASA's Hubble Space Telescope shows for the first time the inner region of a 200-billion mile diameter dust disk around the star Beta Pictoris. This region has long been hidden from ground-based telescopes because of the glare from the central star. The disk is slightly warped. If the warp were there when the star formed, it would long since have flattened out, unless it is produced and maintained by the gravitational pull of a planet. The suspected planet would dwell inside a five-billion mile diameter clear zone inside the inner edge of the disk. Top This is a visible light image of the disk, which appears spindle-like because it is tilted nearly edge-on to our view. The disk is made up of microscopic dust grains of ices and silicate particles, and shines by reflected light from the star. This image indicates that the central clearing is occupied by one or more planets which agglomerated out of the disk and then swept out smaller particles. The bright star, which lies at the center of the disk, is blocked out in this image. Bottom False-color is applied through image processing to accentuate details in the disk structure. Hubble reveals that the pink-white inner edge of the disk is slightly tilted from the plane of the outer disk (red-yellow-green) as identified by a dotted line. A simple explanation is that a large planet is pulling on the disk. It is not possible to see the planet directly because it is close to the star, and perhaps a billion-times fainter. This image was taken with the Wide Field Planetary Camera 2 in January 1995. The star is located 50 light-years away in the southern constellation Pictor (Painter's Easel). Beta Pictoris is a main sequence star, slightly hotter than our Sun. Credit: Chris Burrows, Space Telescope Science Institute (STScI) the European Space Agency (ESA), J. Krist (STScI), the WFPC2 IDT team, and NASA