|
|
HH46/47
| Title |
HH46/47 |
| Description |
This image from NASA's Spitzer Space Telescope transforms a dark cloud into a silky translucent veil, revealing the molecular outflow from an otherwise hidden newborn star. Using near-infrared light, Spitzer pierces through the dark cloud to detect the embedded outflow in an object called HH 46/47. Herbig-Haro (HH) objects are bright, nebulous regions of gas and dust that are usually buried within dark clouds. They are formed when supersonic gas ejected from a forming protostar, or embryonic star, interacts with the surrounding interstellar medium. These young stars are often detected only in the infrared. The Spitzer image was obtained with the infrared array camera. Emission at 3.6 microns is shown as blue, emission from 4.5 and 5.8 microns has been combined as green, and 8.0 micron emission is depicted as red. HH 46/47 is a striking example of a low mass protostar ejecting a jet and creating a bipolar, or two-sided, outflow. The central protostar lies inside a dark cloud (known as a 'Bok globule') which is illuminated by the nearby Gum Nebula. Located at a distance of 1140 light-years and found in the constellation Vela, the protostar is hidden from view in the visible-light image (inset). With Spitzer, the star and its dazzling jets of molecular gas appear with clarity. The 8-micron channel of the infrared array camera is sensitive to emission from polycyclic aromatic hydrocarbons. These organic molecules, comprised of carbon and hydrogen, are excited by the surrounding radiation field and become luminescent, accounting for the reddish cloud. Note that the boundary layer of the 8-micron emission corresponds to the lower right edge of the dark cloud in the visible-light picture. Outflows are fascinating objects, since they characterize one of the most energetic phases of the formation of low-mass stars (like our Sun). The jets arising from these protostars can reach sizes of trillions of miles and velocities of hundreds of thousands miles per hour. Outflows are clear evidence of the presence of a process that creates supersonic beams of gas. This mechanism is tightly bound to the presence of circumstellar discs which surround the young stars. Such discs are likely to contain the materials from which planetary systems form. Our Sun probably underwent a similar process some 4.5 billion years ago. Hence the interest in understanding how quickly and efficiently this mass accretion and loss process takes place in protostars. |
|
HH46/47
| Title |
HH46/47 |
| Description |
This image from NASA's Spitzer Space Telescope transforms a dark cloud into a silky translucent veil, revealing the molecular outflow from an otherwise hidden newborn star. Using near-infrared light, Spitzer pierces through the dark cloud to detect the embedded outflow in an object called HH 46/47. Herbig-Haro (HH) objects are bright, nebulous regions of gas and dust that are usually buried within dark clouds. They are formed when supersonic gas ejected from a forming protostar, or embryonic star, interacts with the surrounding interstellar medium. These young stars are often detected only in the infrared. The Spitzer image was obtained with the infrared array camera. Emission at 3.6 microns is shown as blue, emission from 4.5 and 5.8 microns has been combined as green, and 8.0 micron emission is depicted as red. HH 46/47 is a striking example of a low mass protostar ejecting a jet and creating a bipolar, or two-sided, outflow. The central protostar lies inside a dark cloud (known as a 'Bok globule') which is illuminated by the nearby Gum Nebula. Located at a distance of 1140 light-years and found in the constellation Vela, the protostar is hidden from view in the visible-light image (inset). With Spitzer, the star and its dazzling jets of molecular gas appear with clarity. The 8-micron channel of the infrared array camera is sensitive to emission from polycyclic aromatic hydrocarbons. These organic molecules, comprised of carbon and hydrogen, are excited by the surrounding radiation field and become luminescent, accounting for the reddish cloud. Note that the boundary layer of the 8-micron emission corresponds to the lower right edge of the dark cloud in the visible-light picture. Outflows are fascinating objects, since they characterize one of the most energetic phases of the formation of low-mass stars (like our Sun). The jets arising from these protostars can reach sizes of trillions of miles and velocities of hundreds of thousands miles per hour. Outflows are clear evidence of the presence of a process that creates supersonic beams of gas. This mechanism is tightly bound to the presence of circumstellar discs which surround the young stars. Such discs are likely to contain the materials from which planetary systems form. Our Sun probably underwent a similar process some 4.5 billion years ago. Hence the interest in understanding how quickly and efficiently this mass accretion and loss process takes place in protostars. |
|
HH46/47
| Title |
HH46/47 |
| Description |
This image from NASA's Spitzer Space Telescope transforms a dark cloud into a silky translucent veil, revealing the molecular outflow from an otherwise hidden newborn star. Using near-infrared light, Spitzer pierces through the dark cloud to detect the embedded outflow in an object called HH 46/47. Herbig-Haro (HH) objects are bright, nebulous regions of gas and dust that are usually buried within dark clouds. They are formed when supersonic gas ejected from a forming protostar, or embryonic star, interacts with the surrounding interstellar medium. These young stars are often detected only in the infrared. The Spitzer image was obtained with the infrared array camera. Emission at 3.6 microns is shown as blue, emission from 4.5 and 5.8 microns has been combined as green, and 8.0 micron emission is depicted as red. HH 46/47 is a striking example of a low mass protostar ejecting a jet and creating a bipolar, or two-sided, outflow. The central protostar lies inside a dark cloud (known as a 'Bok globule') which is illuminated by the nearby Gum Nebula. Located at a distance of 1140 light-years and found in the constellation Vela, the protostar is hidden from view in the visible-light image (inset). With Spitzer, the star and its dazzling jets of molecular gas appear with clarity. The 8-micron channel of the infrared array camera is sensitive to emission from polycyclic aromatic hydrocarbons. These organic molecules, comprised of carbon and hydrogen, are excited by the surrounding radiation field and become luminescent, accounting for the reddish cloud. Note that the boundary layer of the 8-micron emission corresponds to the lower right edge of the dark cloud in the visible-light picture. Outflows are fascinating objects, since they characterize one of the most energetic phases of the formation of low-mass stars (like our Sun). The jets arising from these protostars can reach sizes of trillions of miles and velocities of hundreds of thousands miles per hour. Outflows are clear evidence of the presence of a process that creates supersonic beams of gas. This mechanism is tightly bound to the presence of circumstellar discs which surround the young stars. Such discs are likely to contain the materials from which planetary systems form. Our Sun probably underwent a similar process some 4.5 billion years ago. Hence the interest in understanding how quickly and efficiently this mass accretion and loss process takes place in protostars. |
|
Herbig-Haro 46/47
| Title |
Herbig-Haro 46/47 |
| Description |
This 18-second animation zooms in on Herbig-Haro 46/47 and its embedded protostar with molecular outflows. Spitzer/IRAC lifts the cosmic veil and transforms the dark and opaque cloud seen at visible light wavelengths to a spectacular view of a previously unseen protostar and its bipolar outflows. |
|
ROSAT Explores The X-Ray Sky
| Title |
ROSAT Explores The X-Ray Sky |
| Explanation |
Launched in 1990, the orbiting ROSAT observatory [ http://heasarc.gsfc.nasa.gov/docs/rosat/rosat.html ] explored the Universe by viewing the entire sky in x-rays [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/ history1_xray.html ] -- photons with about 1,000 times more energy than visible light. This ROSAT survey [ http://www.xray.mpe.mpg.de/rosat/survey/sxrb/12/ass.html ] produced the sharpest, most sensitive image of the x-ray sky to date. The all-sky image is shown with the plane of our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ] running horizontally through the center. Both x-ray brightness and relative energy are represented with red, green, and blue colors indicating three x-ray energy ranges (from lowest to highest). Bright x-ray spots near the galactic plane are within our own Milky Way. The brightest region (right of center) is toward the Vela Pulsar [ http://antwrp.gsfc.nasa.gov/apod/ap000609.html ] and the Puppis supernova remnant [ http://antwrp.gsfc.nasa.gov/apod/ap991209.html ]. Bright sources beyond our Galaxy are also apparent, notably the Virgo cluster of galaxies [ http://www.seds.org/messier/more/virgo.html ] (near top right) and the Large Magellanic Cloud (LMC) [ http://www.seds.org/messier/xtra/ngc/lmc.html ]. The LMC is easy to find here as several of the black stripes (blank areas caused by missing data) seem to converge on its position (lower right). Over large areas of the sky a general diffuse background of x-rays [ http://chandra.harvard.edu/press/00_releases/ press_011400bg.html ] dominates. Hot gas in our own Galaxy provides much of this background and gives rise to the grand looping structures [ http://antwrp.gsfc.nasa.gov/apod/ap990503.html ] visible in the direction of the galactic center (image center). Unresolved extragalactic sources also add to this background, particularly above and below the plane. Despite the x-ray sky's exotic appearance, a very familiar feature is visible - the gas and dust clouds which line the plane of our galaxy absorb x-rays as well as optical light and produce the dark bands running through the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap000629.html ]. |
|
Vela Supernova Remnant in Vi
…
| Title |
Vela Supernova Remnant in Visible Light |
| Explanation |
The explosion is over but the consequences continue. About eleven thousand years ago a star in the constellation of Vela [ http://www.hawastsoc.org/deepsky/vel/index.html ] could be seen to explode [ http://www.youtube.com/watch?v=gL1xUWgBlFw ], creating a strange point of light briefly visible to humans living near the beginning of recorded history [ http://en.wikipedia.org/wiki/Cave_painting ]. The outer layers of the star crashed into the interstellar medium [ http://antwrp.gsfc.nasa.gov/apod/ap020210.html ], driving a shock wave [ http://antwrp.gsfc.nasa.gov/apod/ap020313.html ] that is still visible today. A roughly spherical, expanding shock wave is visible in X-rays [ http://antwrp.gsfc.nasa.gov/apod/ap960612.html ]. The above image [ http://www.skyfactory.org/vela/vela.htm ] captures much of that filamentary and gigantic shock in visible light [ http://imagers.gsfc.nasa.gov/ems/visible.html ], spanning almost 100 light years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] and appearing twenty times the diameter of the full moon [ http://antwrp.gsfc.nasa.gov/apod/ap051113.html ]. As gas flies away from the detonated star, it decays [ http://imagine.gsfc.nasa.gov/docs/features/exhibit/cgro_snr.html ] and reacts with the interstellar medium, producing light in many different colors and energy bands. Remaining at the center of the Vela Supernova Remnant [ http://en.wikipedia.org/wiki/Vela_Supernova_Remnant ] is a pulsar [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/pulsars.html ], a star as dense as nuclear matter that completely rotates more than ten times in a single second. |
|
Star-Forming Region RCW38 fr
…
| Title |
Star-Forming Region RCW38 from 2MASS |
| Explanation |
The star cluster in RCW38 was hiding. Looking at the star forming region [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ] RCW38 [ http://www.ipac.caltech.edu/2mass/gallery/showcase/rcw38/caption.html ] will not normally reveal most of the stars in this cluster. The reason is that the open cluster [ http://antwrp.gsfc.nasa.gov/apod/open_clusters.html ] is so young that it is still shrouded in thick dust [ http://antwrp.gsfc.nasa.gov/apod/ap990509.html ] that absorbs visible light. This dust typically accompanies the gas that condenses to form young stars. When viewed in infrared [ http://www.ipac.caltech.edu/Outreach/Edu/infrared.html ] light, however, many stars in RCW38 are revealed, because dust is less effective at absorbing infrared light. The above representative-color image [ http://www.ipac.caltech.edu/2mass/gallery/showcase/rcw38/index.html ] mosaic of RCW38 taken by the 2MASS sky survey [ http://www.ipac.caltech.edu/2mass/overview/about2mass.html#about ] in infrared light shows not only many bright blue stars from the star cluster but clouds of brightly emitting gas [ http://antwrp.gsfc.nasa.gov/apod/emission_nebulae.html ] and dramatic lanes of dark dust. RCW38 [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1987MNRAS.228..721M ] spans about 10 light-years [ http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html ] and is located about 5500 light years away towards the constellation [ http://www.astro.wisc.edu/~dolan/constellations/extra/constellations.html ] of Vela [ http://www.astronomical.org/constellations/vel.html ]. |
|
The COMPTEL Gamma-Ray Sky
| Title |
The COMPTEL Gamma-Ray Sky |
| Explanation |
This premier gamma-ray view of the sky was produced by the COMPTEL instrument [ http://wwwgro.unh.edu:8080/comptel/comptel_main.html ] onboard NASA's orbiting Compton Gamma Ray Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap951129.html ]. The entire sky is seen projected on a coordinate system centered on our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap960213.html ] with the plane of the Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] running across the middle of the picture. Gamma-ray intensity is represented by a false color map - low (blue) to high (white). COMPTEL's sensitivity to gamma-rays [ http://wwwgro.unh.edu:8080/comptel/comptel_highlights.html ] which have over 1 million times the energy of visible light photons reveals the locations of some of the Galaxy's most exotic objects. The brightest source, the Crab pulsar [ http://antwrp.gsfc.nasa.gov/apod/ap951122.html ], is located near the plane of the Galaxy on the far right. Moving along the plane from the Crab, more than halfway toward the galactic center, another bright gamma-ray source, the Vela pulsar [ http://heasarc.gsfc.nasa.gov/cossc/descriptions/egret_pulsars.html ], appears. The galactic center itself, along with the famous black hole candidate Cygnus X-1 [ http://www.owlnet.rice.edu/~spac250/steve/ident.html ] (near the plane, halfway from the center to the left edge) are also seen as bright sources. Both above and below the plane, spots of gamma-ray emission due to distant active galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap951023.html ] are also visible. |
|
ROSAT Explores the X-Ray Sky
| Title |
ROSAT Explores the X-Ray Sky |
| Explanation |
Launched in 1990, the orbiting ROSAT observatory [ http://legacy.gsfc.nasa.gov/docs/heasarc/missions/rosat.html ] explored the Universe by viewing the entire sky in x-rays [ http://heasarc.gsfc.nasa.gov/docs/learning_center/ basic/xray/xray_information.html ] - photons with about 1,000 times more energy than visible light [ http://heasarc.gsfc.nasa.gov/docs/learning_center/ basic/emspectrum.html ]. This ROSAT survey [ http://www.rosat.mpe-garching.mpg.de/survey/sxrb/ ] produced the sharpest, most sensitive image of the x-ray sky to date. The all-sky image is shown with the plane of our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap960213.html ] running horizontally through the center. Both x-ray brightness and relative energy are represented with red, green, and blue colors indicating three x-ray energy ranges (from lowest to highest). Bright x-ray spots near the galactic plane are within our own Milky Way. The brightest region (right of center) is toward the Vela Pulsar and the Puppis supernova remnant [ http://lheawww.gsfc.nasa.gov/users/jonathan/outreach_pages/ neutron_stars.html ]. Bright sources beyond our Galaxy are also apparent, notably the Virgo cluster of galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap960419.html ] (near top right) and the Large Magellanic Cloud (LMC) [ http://antwrp.gsfc.nasa.gov/apod/ap950918.html ]. The LMC is easy to find here as several of the black stripes (blank areas caused by missing data) seem to converge on its position (lower right). Over large areas of the sky a general diffuse background of x-rays dominates [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ%2E%2E%2E454%2E%2E643S&db_key=AST ]. Hot gas in our own Galaxy provides much of this background and gives rise to the grand looping structures visible in the direction of the galactic center (image center). Unresolved extragalactic sources also add to this background, particularly above and below the plane. Despite the x-ray sky's exotic appearance, a very familiar feature is visible - the gas and dust clouds which line the plane of our galaxy absorb x-rays as well as optical light and produce the dark bands running through the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap960605.html ]. |
|
Young Star, Dark Cloud
| Title |
Young Star, Dark Cloud |
| Explanation |
High-speed outflows of molecular gas from a young stellar object glow in infrared light, revealing themselves in this recent false-color image from the Spitzer Space Telescope [ http://www.spitzer.caltech.edu/Media/releases/ssc2003-06/ ssc2003-06f.shtml ]. Cataloged as [ http://www-astro.phast.umass.edu/catalogs/HHcat/ HHintro.html ] HH (Herbig-Haro) 46/47 the infrared source [ http://coolcosmos.ipac.caltech.edu/image_galleries/ ir_zoo/horse.html ] is lodged within a dark nebula or Bok globule - near the lower right corner of the dark nebula in the optical inset - that is largely opaque when viewed [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ multiwavelength_astronomy/multiwavelength_astronomy/ index.html ] in visible light. The energetic outflow [ http://hubblesite.org/newscenter/newsdesk/archive/ releases/1995/24/image/a ] features extend for nearly a light-year, burrowing into the dark interstellar material, and are attributed to [ http://photojournal.jpl.nasa.gov/catalog/PIA04940 ] early stages in the life of a sun-like star. They may well represent a phase of our own Sun's evolution [ http://www.columbia.edu/~ah297/unesa/sun/ sun-chapter5.html ] which took place some 4.5 billion years ago, along with the formation of our solar system from a circumstellar disk [ http://antwrp.gsfc.nasa.gov/apod/ap030208.html ]. A tantalizing [ http://planetquest.jpl.nasa.gov/ ] object to explore with Spitzer's infrared [ http://www.spitzer.caltech.edu/science/whyir/ index.shtml ] capabilities, this young star system [ http://arxiv.org/abs/astro-ph/0304258 ] is relatively nearby, located only some 1,140 light-years distant in the nautical constellation Vela [ http://www.hawastsoc.org/deepsky/vel/index.html ]. |
|
Star-Forming Region RCW38
| Title |
Star-Forming Region RCW38 |
| Explanation |
Star cluster RCW38 was hiding. This open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap980329.html ] of stars is located about 5000 light years away towards the constellation of Vela [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Vela.html ]. Looking there will not normally reveal most of the stars in this cluster, though. The reason is that the open cluster [ http://antwrp.gsfc.nasa.gov/apod/ap980803.html ] is so young that it is still shrouded in thick dust [ http://antwrp.gsfc.nasa.gov/apod/ap980104.html ] that absorbs visible light. This dust typically accompanies the gas that condenses to form young stars [ http://antwrp.gsfc.nasa.gov/apod/ap980412.html ]. When viewed in infrared light [ http://www.ipac.caltech.edu/Outreach/Edu/discovery.html ], however, the star cluster in RCW38 [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1987MNRAS.228..721M ] is revealed, because dust is less effective at absorbing infrared light. The above photograph [ http://www.eso.org/outreach/press-rel/pr-1998/pr-19-98.html ] was one of the first ever taken with the new Infrared Spectrometer and Array Camera [ http://www.eso.org/instruments/isaac/ ] (ISAAC) affixed to the 8.2-meter Very Large Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap960901.html ]. |
|
|
