|
|
Tiny Particles, So Far Away
| Title |
Tiny Particles, So Far Away |
| Description |
NASA's Spitzer Space Telescope recently captured these images of the star Vega, located 25 light years away in the constellation Lyra. Spitzer was able to detect the heat radiation from the cloud of dust around the star and found that the debris disk is much larger than previously thought. This side-by-side comparison, taken by Spitzer's multiband imaging photometer, shows the warm infrared glows from dust particles orbiting the star at wavelengths of 24 microns (on the left in blue) and 70 microns (on the right in red). Both images show a very large, circular and smooth debris disk. The disk radius extends to at least 815 astronomical units. (One astronomical unit is the distance from Earth to the Sun, which is 150-million kilometers or 93-million miles). Scientists compared the surface brightness of the disk in the infrared wavelengths to determine the temperature distribution of the disk and then refer the corresponding particle size in the disk. Most of the particles in the disk are only a few microns in size, or 100 times smaller than a grain of Earth sand. These fine dust particles originate from collisions of embryonic planets near the star at a radius of approximately 90 astronomical units, and are then blown away by Vega's intense radiation. The mass and short lifetime of these small particles indicate that the disk detected by Spitzer is the aftermath of a large and relatively recent collision, involving bodies perhaps as big as the planet Pluto. The images are 3 arcminutes on each side. North is oriented upward and east is to the left. |
|
Massive Smash-Up at Vega
| Title |
Massive Smash-Up at Vega |
| Description |
This artist concept illustrates how a massive collision of objects, perhaps as large as the planet Pluto, smashed together to create the dust ring around the nearby star Vega. New observations from NASA's Spitzer Space Telescope indicate the collision took place within the last one million years. Astronomers think that embryonic planets smashed together, shattered into pieces, and repeatedly crashed into other fragments to create ever finer debris. In the image, a collision is seen between massive objects that measured up to 2,000 kilometers (about 1,200 miles) in diameter. Scientists say the big collision initiated subsequent collisions that created dust particles around the star that were a few microns in size. Vega's intense light blew these fine particles to larger distances from the star, and also warmed them to emit heat radiation that can be detected by Spitzer's infrared detectors. |
|
Lockheed Vega Air Express
| Title |
Lockheed Vega Air Express |
| Full Description |
Lockheed Vega Air Express. Frank M. Hawks broke the transcontinental speed record in this plane. It was the first production aircraft with the NACA cowling, 1929. |
| Date |
01/01/1929 |
| NASA Center |
Langley Research Center |
|
Astronomers Use Hubble to 'W
…
| Title |
Astronomers Use Hubble to 'Weigh' Dog Star's Companion |
|
Astronomers Use Hubble to 'W
…
| Title |
Astronomers Use Hubble to 'Weigh' Dog Star's Companion |
|
A83-0499-3
Photographer: N/A Lockheed V
…
7/13/93
| Description |
Photographer: N/A Lockheed Vega Cockpit |
| Date |
7/13/93 |
|
AC83-0768-4
Photographer: IRAS Imagery T
…
11/9/83
| Description |
Photographer: IRAS Imagery This artist's concept illustrates the ring of material discovered by the Infrared Astronomical Satellite around the star Vega. IRAS scientists believe the material probably consists of dust and small objects resembling meteors. As depicted here, the ring of particles is thin enough toallow light from distant stars to shine through. The plane of the Milky Way is to the right. |
| Date |
11/9/83 |
|
Mato Vega Fire, Colorado
| Title |
Mato Vega Fire, Colorado |
| Description |
In the Sangre de Cristo Mountains of southern Colorado, the Mato Vega Fire burned in timber, debris left over from logging, and grass in mid-June 2006. This image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite on June 20, 2006. The locations in which MODIS detected actively burning fire are outlined in red. The fire is spreading smoke out over the plains to the northeast. According to the National Interagency Fire Center [ http://www.nifc.gov/information.html ] report from June 21, the fire was 8,960 acres and only 5 percent contained. This image has a spatial resolution (level of detail) of 250 meters per pixel. The large image shows a wider area at the same resolution. The MODIS Rapid Response System provides this image at additional resolutions. [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?AERONET_BSRN_BAO_Boulder ] NASA image courtesy the MODIS Rapid Response Team, [ http://rapidfire.sci.gsfc.nasa.gov ] Goddard Space Flight Center |
|
Asteroid 2002 NY40
| Title |
Asteroid 2002 NY40 |
| Explanation |
Asteroid 2002 NY40 [ http://science.nasa.gov/headlines/y2002/ 30jul_ny40.htm ] will fly by planet Earth early in the morning August 18 Universal Time (late in the evening August 17 Eastern Daylight Time). Approaching to within [ http://neo.jpl.nasa.gov/ ] about 530,000 kilometers or 1.3 times the Earth-Moon distance 2002 NY40 [ http://neo.jpl.nasa.gov/cgi-bin/db?name=2002+NY40 ] will definitely not be close enough to pose any danger of collision. But it will be close enough and just bright enough for experienced skygazers to see this 800 meter wide space rock [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ asteroids.html ] in a small telescope or binoculars as it glides quickly through northern skies [ http://science.nasa.gov/headlines/y2002/images/ny40/ skymap_ut.gif ] past the bright star Vega. It will also be close enough to ping with radar [ http://echo.jpl.nasa.gov/ ], and asteroid hunters using the large Arecibo radio telescope [ http://antwrp.gsfc.nasa.gov/apod/ap981129.html ] in Puerto Rico expect to determine the three dimensional outline of 2002 NY40. Similar investigations of other near Earth [ http://antwrp.gsfc.nasa.gov/apod/ap970120.html ] asteroids have revealed some surprising shapes [ http://antwrp.gsfc.nasa.gov/apod/ap000510.html ]. In this five minute time exposure, recorded at Cerro Tololo [ http://www.ctio.noao.edu/ ] Inter-American Observatory on August 14, 2002 NY40 shows itself as a long smudge as it moves against a background of faint stars in the constellation Aquarius [ http://www.windows.ucar.edu/tour/link=/the_universe/ Constellations/aquarius.html ]. |
|
Vega Credit: D. Moffatt (DOA
…
| Title |
Vega Credit: D. Moffatt (DOA [ http://www.dao.nrc.ca/ ]), ScienceWeb [ http://scienceweb.dao.nrc.ca/ ], Starry Messenger Communications |
| Explanation |
Vega is a bright blue star 25 light years away. Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=06/15/1996&field=ScriptAirDate&html=Test+Request+Date ] is the brightest star in the Summer Triangle [ http://eagle.online.discovery.com/DCO/doc/1012/world/starshack/starshack080796/starshack.html ], a group of stars easily visible summer evenings in the northern hemisphere. The name Vega [ http://www.astro.wisc.edu/~dolan/constellations/hr/7001.html ] derives from Arabic origins, and means "stone eagle." 4,000 years ago, however, Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=05/20/1995&field=ScriptAirDate&html=Test+Request+Date ] was known by some as "Ma'at" - one example of ancient human astronomical knowledge and language. 14,000 years ago, Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=07/10/1994&field=ScriptAirDate&html=Test+Request+Date ], not Polaris [ http://www.arcorp.com/polaris.html ], was the north star [ http://antwrp.gsfc.nasa.gov/apod/ap961201.html ]. Vega [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ%2E%2E%2E450%2E%2E364G&db_key=AST&nosetcookie=1 ] is the fifth brightest star in the night sky, and has a diameter almost three times that of our Sun. Life [ http://www.seti-inst.edu/phoenix/contact.html ] bearing planets, rich in liquid water, could possibly exist around Vega [ http://lsnt7.lightspeed.net/~astronomy/lifezones/lifezones.html ]. The above picture [ http://www.jpl.nasa.gov/comet/moffatt1.html ], taken in January, finds Vega, the Summer Triangle [ http://antwrp.gsfc.nasa.gov/apod/ap961212.html ], and Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970610.html ] high above Victoria [ http://www.city.victoria.bc.ca/ ], British Columbia [ http://www.gov.bc.ca/ ], Canada. |
|
Three Dusty Stars
| Title |
Three Dusty Stars |
| Explanation |
These separate radio images [ http://www.jach.hawaii.edu/~wsh/press/dustydisks.html ] reveal three dusty debris disks [ http://www.jach.hawaii.edu/~wsh/press/images.html ] surrounding three bright, young, nearby stars - evidence for solar systems [ http://wwwusr.obspm.fr/departement/darc/planets/encycl.html ] in formation. From left to right are the stars Fomalhaut [ http://www.astro.wisc.edu/~dolan/constellations/hr/8728.html ], Beta Pictoris [ http://antwrp.gsfc.nasa.gov/apod/ap980122.html ], and Vega [ http://antwrp.gsfc.nasa.gov/apod/ap970715.html ], their positions indicated by star symbols. The false color maps show the intensity of submillimeter radio emission from the surrounding dust. Next to each dust "disk", a vertical bar illustrates the present size of our own solar system. These observations are likely examples of what our solar system [ http://antwrp.gsfc.nasa.gov/apod/ap961214.html ] would have looked like to distant radio astronomers [ http://www.seti-inst.edu/phoenix/contact.html ] when it was only a few hundred million years old! Astronomers speculate that bright blobs of emission near Vega and Beta Pictoris may represent dust clouds around developing giant planets. The radio images were made using detectors [ http://www.jach.hawaii.edu/JCMT/scuba/ ] cooled to near absolute zero [ http://www.unidata.ucar.edu/staff/blynds/tmp.html ] and the James Clerk Maxwell Telescope [ http://www.jach.hawaii.edu/JCMT/home.html ] at Mauna Kea Observatory in Hawaii [ http://antwrp.gsfc.nasa.gov/apod/ap970302.html ]. |
|
HR 4796A: Not Saturn
| Title |
HR 4796A: Not Saturn |
| Explanation |
These are not false-color renderings of the latest observations of Saturn's magnificent rings [ http://antwrp.gsfc.nasa.gov/apod/ap980424.html ]. Instead, the panels show a strikingly similar system on a much larger scale - a ring around the young, Vega-like star, HR 4796A [ http://oposite.stsci.edu/pubinfo/pr/1999/03/b.html ], located about 200 light-years from Earth. Probably composed of dusty debris ground from colliding planetesimals, this ring is confined to a zone less than 17 AU wide (1 AU equals the Earth-Sun distance) and girdles the star at a radius of about 70 AU, roughly twice the orbital radius of Neptune. In analogy with the relationship of Saturn's rings and moons [ http://ringmaster.arc.nasa.gov/reference/abstracts/cuzzi1984_01.html ], this circumstellar ring could be held in place by forces due to planets - shepherding planetary bodies or the gravitational influence of larger planets orbiting closer to the parent star. In any event, because the ring would not survive long without something to keep it there, astronomers consider its presence strong evidence for unseen planetary bodies [ http://www.generation.net/~mariob/astro/xtrasol.htm ] around HR 4796A. The top panels show the false-color images [ http://nicmosis.as.arizona.edu:8000/AAS99/hr4796_postrev5.ps ] at two infrared wavelengths from the Hubble Space Telescope's NICMOS instrument [ http://nicmos.as.arizona.edu/ ], and the bottom panels trace the corresponding image contours. At the center of each, the overwhelming light of HR 4796A has been masked to reveal the fainter circumstellar ring. |
|
Polaris: The North Star
| Title |
Polaris: The North Star |
| Explanation |
Polaris is quite an unusual star. First, Polaris [ http://einstein.stcloudstate.edu/Dome/constellns/polaris.html ] is the nearest bright star to the north spin axis [ http://antwrp.gsfc.nasa.gov/apod/ap980912.html ] of the Earth. Therefore, as the Earth turns, stars appear to rotate around Polaris [ http://www.physics.pacificu.edu/sci170/movies/nightly.html ], making it the North Star [ http://www.physics.csbsju.edu/astro/CS/CS.03.html ]. Since no bright star is near the south spin axis of the Earth, there is currently no South Star [ http://antwrp.gsfc.nasa.gov/apod/ap960503.html ]. Thousands of years ago, Earth's spin axis pointed in a slightly different direction [ http://www.fourmilab.ch/yoursky/help/precession.html ], and Vega [ http://antwrp.gsfc.nasa.gov/apod/ap980823.html ] was the North Star. Although Polaris [ http://www.seds.org/~spider/spider/Misc/alphaUMi.html ] is not the brightest star [ http://www.astro.wisc.edu/~dolan/constellations/extra/brightest.html ] on the sky, it is easily located because it is nearly aligned with two stars in the cup of the Big Dipper [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Ursa_Major.html ], and is the last star in the handle of the Little Dipper [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Ursa_Minor.html ]. In the above picture, Polaris [ http://www.astro.wisc.edu/~dolan/constellations/hr/0424.html ] is the brightest star on the right, above the fleeting streak of a Perseid meteor [ http://antwrp.gsfc.nasa.gov/apod/ap960809.html ]. The surface of Polaris slowly pulsates [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1994PASP..106..964B ], causing the star to change its brightness by a few percent over the course of a few days. This rare Cepheid variability [ http://antwrp.gsfc.nasa.gov/apod/ap960110.html ] of Polaris is, oddly enough, itself changing [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998AJ....116..936K ]. |
|
Lockheed Vega Air Express
| Title |
Lockheed Vega Air Express |
| Description |
Lockheed Vega Air Express. Frank M. Hawks broke transcontinental speed record in this plane. It was the first production aircraft with the NACA cowling, 1929. |
| Date |
02.14.1929 |
|
Lockheed Y1C-12 (C-12)
| Title |
Lockheed Y1C-12 (C-12) |
| Description |
The Lockheed Y1C-12 was a U. S. Army procured example of the Lockheed Vega. The military used the craft as a high-speed transport. The most famous Vega built was Oklahoman Wiley Post's "Winnie Mae." The Y1C-12, like other Vegas, had a wooden monocoque fuselage and a shoulder mounted wing. |
| Date |
02.13.1931 |
|
Altair
| Title |
Altair |
| Description |
For the first time ever, a star spinning so fast its mid-section is stretched out has been directly measured by an ultra-high-resolution NASA telescope system on Palomar Mountain near San Diego."Measuring the shape of this star, Altair, was as difficult as standing in Los Angeles, looking at a hen's egg in New York, and trying to prove that it's oval-shaped and not circular," said Dr. Charles Beichman, chief scientist for astronomy and physics at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Altair is a well-known member of the Summer Triangle, clearly visible in the summer night sky across the United States. Scientists using the Palomar Testbed Interferometer, which links multiple telescopes, measured the star's radius at different angles on the sky. They noticed the size of the star varied with changing angles, which was the first tip-off that Altair is not perfectly round."This surprising observation led to a bit of challenging detective work to properly interpret the data," said principal investigator Dr. Gerard van Belle of JPL. "We measured the size of another star, Vega, at the same time, which didn't change with angle, so we knew this wasn't just a fluke of the telescope." Previous studies of Altair raised the prospect that the star might have midriff bulge, but never before had the shape been measured directly. Earlier measurements of the star's spectrum, or light-wave pattern, had hinted that Altair was rotating very fast. When a gaseous orb, like a star, spins fast enough, it tends to expand at the middle, like a beach ball that is squeezed at the top and bottom. Altair is a perfect example -- it rotates at least once every 10.4 hours, and the new Palomar observations reveal the diameter at its equator is at least 14 percent greater than at its poles. For a star that spins slowly, this effect is miniscule. For example, our Sun rotates once every 30 days and has an equator only .001 percent greater in diameter than its poles. By measuring Altair's size at separate positions along its edge, van Belle and his colleagues determined that Altair rotates at a speed of at least 210 kilometers per second (470,000 miles per hour) at the equator. Future studies may pin down the speed more precisely."Determining the shape of another star helps us learn about the forces that control the shape and structure of all stars, including our star, the Sun," Beichman said. "This tells us more about the Sun's behavior and ultimate fate." The Palomar Testbed Interferometer has three 50-centimeter (20-inch) telescopes. To study Altair, the telescopes were used two at a time. The combined light from the telescope pairs provided sharpness comparable to a telescope as large as a football field."Altair is the twelfth brightest star in the sky -- you'd think that everything there is to know about this star would have been discovered already," said co-investigator Dr. David Ciardi of the University of Florida, Gainesville. "It's a good example of, the surprises you're going to encounter when you are able to look at even familiar stars with unprecedented resolution." The Palomar Testbed Interferometer is paving the way for the Keck Interferometer, Space Interferometry Mission and Terrestrial Planet Finder, all part of NASA's Origins program. The program will hunt for Earthlike planets that might harbor life around other stars. "In the long run, we'll use these interferometric capabilities to search for planets around nearby stars. This is an important first step," said Beichman. Van Belle and Ciardi co-authored the Altair paper, scheduled to appear in the October 1 issue of the Astrophysical Journal, with Robert Thompson of JPL and the University of Wyoming, Laramie, Dr. Rachel Akeson of the JPL/Caltech Infrared Processing and Analysis Center, Pasadena, Calif., and Dr. Elizabeth Lada of the University of Florida, Gainesville. Their research was funded by NASA's Office of Space Science, Washington, D.C., along with the National Science Foundation. Palomar Observatory is owned and operated by the California Institute of Technology in Pasadena, which also manages JPL for NASA. The Palomar Testbed Interferometer was designed and built by a team of JPL researchers led by Drs. Mark Colavita and Michael Shao. Funded by NASA and managed by JPL, the interferometer is located at the Palomar Observatory near the historic 200-inch Hale Telescope. Images and animation of Altair are available athttp://www.jpl.nasa.gov/images/stars/index.html [ http://www.jpl.nasa.gov/images/stars/index.html ]. Information on the Palomar Testbed Interferometer is available athttp://huey.jpl.nasa.gov/palomar [ http://huey.jpl.nasa.gov/palomar ]. Information on NASA's Origins Program is available athttp://origins.jpl.nasa.gov [ http://origins.jpl.nasa.gov ]. |
| Date |
12.01.1999 |
|
Scout Project
| Title |
Scout Project |
| Description |
Sunset shots of S-131. S-131 launched August 10, 1965. The flight was a success. Notes on the mission remark that the mission demonstrated the fourth-stage interchangeability and air transport demonstration. It was the first flight of the Castor IIA, FW4-S, 75 KS spin motors, Vega Beacon, Autodestruct Module, Dogleg, Transition "E", Ignition monitor and electrostatic experiment. |
| Date |
08.09.1965 |
|
ECHO Project
| Title |
ECHO Project |
| Description |
Sunset shots of S-131. S-131 launched August 10, 1965. The flight was a success. Notes on the mission remark that the mission demonstrated the fourth-stage interchangeability and air transport demonstration. It was the first flight of the Castor IIA, FW4-S, 75 KS spin motors, Vega Beacon, Autodestruct Module, Dogleg, Transition "E", Ignition monitor and electrostatic experiment. |
| Date |
08.27.1965 |
|
Mato Vega Fire, Colorado: Na
…
nasa, nasanaturalhazards
In the Sangre de Cristo Moun
…
Boulder.TMO2006171
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-06-20 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
Boulder.TMO2006171 |
|
Cuzco, Peru: Image of the Da
…
nasa, nasaimageofthedaygalle
…
In the Andes Mountains of so
…
cuzco_AST2006jul18
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-07-18 |
| creator |
NASA -- NASA image courtesy of GSFC/MITI/ERSDAC/JAROS, and the U.S./Japan asterweb.jpl.nasa.gov/ ASTER Science Team. |
| identifier |
cuzco_AST2006jul18 |
|
Tiny Particles, So Far Away
PIA07218
Multiband Imaging Photometer
| Title |
Tiny Particles, So Far Away |
| Original Caption Released with Image |
NASA's Spitzer Space Telescope recently captured these images of the star Vega, located 25 light years away in the constellation Lyra. Spitzer was able to detect the heat radiation from the cloud of dust around the star and found that the debris disc is much larger than previously thought. This side by side comparison, taken by Spitzer's multiband imaging photometer, shows the warm infrared glows from dust particles orbiting the star at wavelengths of 24 microns (figure 2 in blue) and 70 microns (figure 3 in red). Both images show a very large, circular and smooth debris disc. The disc radius extends to at least 815 astronomical units. (One astronomical unit is the distance from Earth to the Sun, which is 150-million kilometers or 93-million miles). Scientists compared the surface brightness of the disc in the infrared wavelengths to determine the temperature distribution of the disc and then infer the corresponding particle size in the disc. Most of the particles in the disc are only a few microns in size, or 100 times smaller than a grain of Earth sand. These fine dust particles originate from collisions of embryonic planets near the star at a radius of approximately 90 astronomical units, and are then blown away by Vega's intense radiation. The mass and short lifetime of these small particles indicate that the disc detected by Spitzer is the aftermath of a large and relatively recent collision, involving bodies perhaps as big as the planet Pluto. The images are 3 arcminutes on each side. North is oriented upward and east is to the left. |
|
Tiny Particles, So Far Away
PIA07218
Multiband Imaging Photometer
| Title |
Tiny Particles, So Far Away |
| Original Caption Released with Image |
NASA's Spitzer Space Telescope recently captured these images of the star Vega, located 25 light years away in the constellation Lyra. Spitzer was able to detect the heat radiation from the cloud of dust around the star and found that the debris disc is much larger than previously thought. This side by side comparison, taken by Spitzer's multiband imaging photometer, shows the warm infrared glows from dust particles orbiting the star at wavelengths of 24 microns (figure 2 in blue) and 70 microns (figure 3 in red). Both images show a very large, circular and smooth debris disc. The disc radius extends to at least 815 astronomical units. (One astronomical unit is the distance from Earth to the Sun, which is 150-million kilometers or 93-million miles). Scientists compared the surface brightness of the disc in the infrared wavelengths to determine the temperature distribution of the disc and then infer the corresponding particle size in the disc. Most of the particles in the disc are only a few microns in size, or 100 times smaller than a grain of Earth sand. These fine dust particles originate from collisions of embryonic planets near the star at a radius of approximately 90 astronomical units, and are then blown away by Vega's intense radiation. The mass and short lifetime of these small particles indicate that the disc detected by Spitzer is the aftermath of a large and relatively recent collision, involving bodies perhaps as big as the planet Pluto. The images are 3 arcminutes on each side. North is oriented upward and east is to the left. |
|
Tiny Particles, So Far Away
PIA07218
Multiband Imaging Photometer
| Title |
Tiny Particles, So Far Away |
| Original Caption Released with Image |
NASA's Spitzer Space Telescope recently captured these images of the star Vega, located 25 light years away in the constellation Lyra. Spitzer was able to detect the heat radiation from the cloud of dust around the star and found that the debris disc is much larger than previously thought. This side by side comparison, taken by Spitzer's multiband imaging photometer, shows the warm infrared glows from dust particles orbiting the star at wavelengths of 24 microns (figure 2 in blue) and 70 microns (figure 3 in red). Both images show a very large, circular and smooth debris disc. The disc radius extends to at least 815 astronomical units. (One astronomical unit is the distance from Earth to the Sun, which is 150-million kilometers or 93-million miles). Scientists compared the surface brightness of the disc in the infrared wavelengths to determine the temperature distribution of the disc and then infer the corresponding particle size in the disc. Most of the particles in the disc are only a few microns in size, or 100 times smaller than a grain of Earth sand. These fine dust particles originate from collisions of embryonic planets near the star at a radius of approximately 90 astronomical units, and are then blown away by Vega's intense radiation. The mass and short lifetime of these small particles indicate that the disc detected by Spitzer is the aftermath of a large and relatively recent collision, involving bodies perhaps as big as the planet Pluto. The images are 3 arcminutes on each side. North is oriented upward and east is to the left. |
|
Tiny Particles, So Far Away
PIA07218
Multiband Imaging Photometer
| Title |
Tiny Particles, So Far Away |
| Original Caption Released with Image |
NASA's Spitzer Space Telescope recently captured these images of the star Vega, located 25 light years away in the constellation Lyra. Spitzer was able to detect the heat radiation from the cloud of dust around the star and found that the debris disc is much larger than previously thought. This side by side comparison, taken by Spitzer's multiband imaging photometer, shows the warm infrared glows from dust particles orbiting the star at wavelengths of 24 microns (figure 2 in blue) and 70 microns (figure 3 in red). Both images show a very large, circular and smooth debris disc. The disc radius extends to at least 815 astronomical units. (One astronomical unit is the distance from Earth to the Sun, which is 150-million kilometers or 93-million miles). Scientists compared the surface brightness of the disc in the infrared wavelengths to determine the temperature distribution of the disc and then infer the corresponding particle size in the disc. Most of the particles in the disc are only a few microns in size, or 100 times smaller than a grain of Earth sand. These fine dust particles originate from collisions of embryonic planets near the star at a radius of approximately 90 astronomical units, and are then blown away by Vega's intense radiation. The mass and short lifetime of these small particles indicate that the disc detected by Spitzer is the aftermath of a large and relatively recent collision, involving bodies perhaps as big as the planet Pluto. The images are 3 arcminutes on each side. North is oriented upward and east is to the left. |
|
Massive Smash-up at Vega
PIA07217
| Title |
Massive Smash-up at Vega |
| Original Caption Released with Image |
This artist concept illustrates how a massive collision of objects perhaps as large as the planet Pluto smashed together to create the dust ring around the nearby star Vega. New observations from NASA's Spitzer Space Telescope indicate the collision took place within the last one million years. Astronomers think that embryonic planets smashed together, shattered into pieces, and repeatedly crashed into other fragments to create ever finer debris. In the image, a collision is seen between massive objects that measured up to 2,000 kilometers (about 1,200 miles) in diameter. Scientists say the big collision initiated subsequent collisions that created dust particles around the star that were a few microns in size. Vega's intense light blew these fine particles to larger distances from the star, and also warmed them to emit heat radiation that can be detected by Spitzer's infrared detectors. |
|
Altair
PIA04204
Palomar Testbed Interferomet
…
| Title |
Altair |
| Original Caption Released with Image |
For the first time ever, a star spinning so fast its mid-section is stretched out has been directly measured by an ultra-high-resolution NASA telescope system on Palomar Mountain near San Diego."Measuring the shape of this star, Altair, was as difficult as standing in Los Angeles, looking at a hen's egg in New York, and trying to prove that it's oval-shaped and not circular," said Dr. Charles Beichman, chief scientist for astronomy and physics at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Altair is a well-known member of the Summer Triangle, clearly visible in the summer night sky across the United States. Scientists using the Palomar Testbed Interferometer, which links multiple telescopes, measured the star's radius at different angles on the sky. They noticed the size of the star varied with changing angles, which was the first tip-off that Altair is not perfectly round. "This surprising observation led to a bit of challenging detective work to properly interpret the data," said principal investigator Dr. Gerard van Belle of JPL. "We measured the size of another star, Vega, at the same time, which didn't change with angle, so we knew this wasn't just a fluke of the telescope." Previous studies of Altair raised the prospect that the star might have midriff bulge, but never before had the shape been measured directly. Earlier measurements of the star's spectrum, or light-wave pattern, had hinted that Altair was rotating very fast. When a gaseous orb, like a star, spins fast enough, it tends to expand at the middle, like a beach ball that is squeezed at the top and bottom. Altair is a perfect example -- it rotates at least once every 10.4 hours, and the new Palomar observations reveal the diameter at its equator is at least 14 percent greater than at its poles. For a star that spins slowly, this effect is miniscule. For example, our Sun rotates once every 30 days and has an equator only .001 percent greater in diameter than its poles. By measuring Altair's size at separate positions along its edge, van Belle and his colleagues determined that Altair rotates at a speed of at least 210 kilometers per second (470,000 miles per hour) at the equator. Future studies may pin down the speed more precisely."Determining the shape of another star helps us learn about the forces that control the shape and structure of all stars, including our star, the Sun," Beichman said. "This tells us more about the Sun's behavior and ultimate fate." The Palomar Testbed Interferometer has three 50-centimeter (20-inch) telescopes. To study Altair, the telescopes were used two at a time. The combined light from the telescope pairs provided sharpness comparable to a telescope as large as a football field."Altair is the twelfth brightest star in the sky -- you'd think that everything there is to know about this star would have been discovered already," said co-investigator Dr. David Ciardi of the University of Florida, Gainesville. "It's a good example of, the surprises you're going to encounter when you are able to look at even familiar stars with unprecedented resolution." The Palomar Testbed Interferometer is paving the way for the Keck Interferometer, Space Interferometry Mission and Terrestrial Planet Finder, all part of NASA's Origins program. The program will hunt for Earthlike planets that might harbor life around other stars. "In the long run, we'll use these interferometric capabilities to search for planets around nearby stars. This is an important first step," said Beichman. Van Belle and Ciardi co-authored the Altair paper, scheduled to appear in the October 1 issue of the Astrophysical Journal, with Robert Thompson of JPL and the University of Wyoming, Laramie, Dr. Rachel Akeson of the JPL/Caltech Infrared Processing and Analysis Center, Pasadena, Calif., and Dr. Elizabeth Lada of the University of Florida, Gainesville. Their research was funded by NASA's Office of Space Science, Washington, D.C., along with the National Science Foundation. Palomar Observatory is owned and operated by the California Institute of Technology in Pasadena, which also manages JPL for NASA. The Palomar Testbed Interferometer was designed and built by a team of JPL researchers led by Drs. Mark Colavita and Michael Shao. Funded by NASA and managed by JPL, the interferometer is located at the Palomar Observatory near the historic 200-inch Hale Telescope. Images and animation of Altair are available at http://www.jpl.nasa.gov/images/stars/index.html [ http://www.jpl.nasa.gov/images/stars/index.html ] . Information on the Palomar Testbed Interferometer is available at http://huey.jpl.nasa.gov/palomar [ http://huey.jpl.nasa.gov/palomar ] . Information on NASA's Origins Program is available at http://origins.jpl.nasa.gov [ http://origins.jpl.nasa.gov ]. |
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![Vega Credit: D. Moffatt (DOA [ http://www.dao.nrc.ca/ ]), ScienceWeb [ http://scienceweb.dao.nrc.ca/ ], Starry Messenger Communications](http://mm04.nasaimages.org/MediaManager/srvr?mediafile=/Size1/NVA2-4-NA/8321/vega_dm.jpg&userid=1&username=admin&resolution=1&servertype=JVA&cid=4&iid=NVA2&vcid=NA&usergroup=NASA_Astronomy_Picture_of_the_Day_Collecti-4-Admin&profileid=16)
