Atlantis Lands in California June 22, 2007Posted by jtintle in Planets, Space Fotos.
Tags: Earth, Edwards Air Force Base, Expedition 15, Johnson Space Center, NASA, Space Shuttle Atlantis, Suni Williams
JOHNSON SPACE CENTER PAO: Landing gear is down and locked. Main gear touchdown. Nose gear touchdown. Atlantis rolling out on Runway 22 at Edwards Air Force Base, wrapping up a 5.8-million-mile mission.
Atlantis completing its 28th mission, leaving the International Space Station with more power-generation capability and bringing home Expedition 15 astronaut Suni Williams after 195 days in space.
ATLANTIS: Houston, Atlantis. Wheels stop.
HOUSTON: Atlantis, Houston. Copy wheels stop. Welcome back.
Congratulations on a great mission. Good job installing S3/S4, continuing to expand the space station in preparation for adding modules from more of our international partners and stepping stones for the rest of the NASA exploration plan.
Eta Carinae: New View of Doomed Star June 21, 2007Posted by jtintle in Deep Space, Space Fotos.
Tags: Chandra X-ray Observatory, Eta Carinae, Goddard Space Flight Center, Hubble Space Telescope, M. Corcoran, NASA, Nebula, SN2006gy, STScI, Supernova
X-ray:NASA/CXC/GSFC/M.Corcoran et al.; Optical: NASA/STScI
Eta Carinae is a mysterious, extremely bright and unstable star located a mere stone’s throw – astronomically speaking – from Earth at a distance of only about 7,500 light years. The star is thought to be consuming its nuclear fuel at an incredible rate, while quickly drawing closer to its ultimate explosive demise. When Eta Carinae does explode, it will be a spectacular fireworks display seen from Earth, perhaps rivaling the moon in brilliance. Its fate has been foreshadowed by the recent discovery of SN2006gy, a supernova in a nearby galaxy that was the brightest stellar explosion ever seen. The erratic behavior of the star that later exploded as SN2006gy suggests that Eta Carinae may explode at any time.
Eta Carinae, a star between 100 and 150 times more massive than the Sun, is near a point of unstable equilibrium where the star’s gravity is almost balanced by the outward pressure of the intense radiation generated in the nuclear furnace. This means that slight perturbations of the star might cause enormous ejections of matter from its surface. In the 1840s, Eta Carinae had a massive eruption by ejecting more than 10 times the mass of the sun, to briefly become the second brightest star in the sky. This explosion would have torn most other stars to pieces but somehow Eta Carinae survived.
The latest composite image shows the remnants of that titanic event with new data from NASA’s Chandra X-ray Observatory and the Hubble Space Telescope. The blue regions show the cool optical emission, detected by Hubble, from the dust and gas thrown off the star. This debris forms a bipolar shell around the star, which lies near the brightest point of the optical emission. This bipolar shell is itself surrounded by a ragged cloud of fainter material. An unusual jet points from the star to the upper left.
Chandra’s data, depicted in orange and yellow, shows the X-ray emission produced as material thrown off Eta Carinae rams into nearby gas and dust, heating gas to temperatures in excess of a million degrees. This hot shroud extends far beyond the cooler, optical nebula and represents the outer edge of the interaction region. The X-ray observations show that the ejected outer material is enriched by complex atoms, especially nitrogen, cooked inside the star’s nuclear furnace and dredged up onto the stellar surface. The Chandra observations also show that the inner optical nebula glows faintly due to X-ray reflection. The X-rays reflected by the optical nebula come from very close to the star itself; these X-rays are generated by the high-speed collision of wind flowing from Eta Carinae’s surface (moving at about 1 million miles per hour) with the wind of the companion star (which is about five times faster).
The companion is not directly visible in these images, but variability in X-rays in the regions close to the star signals the star’s presence. Astronomers don’t know exactly what role the companion has played in the evolution of Eta Carinae, or what role it will play in its future.
vdB 152: Reflection Nebula in Cepheus June 14, 2007Posted by jtintle in Deep Space, Space Fotos.
Tags: Astronomy Picture of the Day, Constellation Cepheus, Giovanni Benintende, Milky Way Galaxy, reflection nebula, VdB 152
Described as a “dusty curtain” or “ghostly apparition”, mysterious reflection nebula vdB 152 really is very faint. It lies about 1400 light-years away, along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of cosmic dust in the region block light from background stars or scatter light from the embedded bright star (top) giving parts of the nebula a characteristic blue color. Ultraviolet light from the star is also thought to cause a dim reddish luminescence in the nebular dust. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through interstellar space is very different from the cloud’s velocity. This deep telescopic image spans about 7 light-years at the estimated distance of vdB 152.
Adding Power June 13, 2007Posted by jtintle in Planets, Space Fotos.
Tags: Earth, extravehicular activity (EVA), International Space Station, Jim Reilly, John "Danny" Olivas, NASA, Solar Array, STS-117
Astronaut Jim Reilly, an STS-117 mission specialist, participated in the mission’s first planned session of extravehicular activity (EVA), as construction resumes on the International Space Station. Among other tasks, Reilly and fellow mission specialist John “Danny” Olivas connected power, data and cooling cables between S1 and S3. They also released the launch restraints from, and deployed the four solar array blanket boxes on S4, and released the cinches and winches holding the photo voltaic radiator on S4. Earth’s horizon and the blackness of space provided the backdrop for the scene.
Tags: Alice C. Quillen, Coronagraph, Fomalhaut, Hubble Space Telescope, Monthly Notices of the Royal Astronomical Society, NASA, National Institutes of Science, University of Rochester
National Institutes of Science and NASA
A young star’s strange elliptical ring of dust likely heralds the presence of an undiscovered Neptune-sized planet, says a University of Rochester astronomer in the latest Monthly Notices of the Royal Astronomical Society. Stars in the early stages of life are surrounded by dust clouds that thin out and dissipate as the star reaches maturity, becoming rings in their final stages. One star, however, has a dust ring that has long puzzled astronomers because it is not centered around the star as usual. Instead, the ring is elliptical, with the parent star off to one side.
“We wanted to know why this ring was off-center,” says Alice C. Quillen, Associate Professor of Astronomy and author of the study. “People guessed there might be a planet in there, but nobody knew where it might be, or how big it might be. Now we’ve got a very good idea.”
Roughly 250 planets have been discovered so far around stars other than our Sun. Most have been revealed by the way the planets influence their parent stars, but Quillen has been working for years on understanding the delicate interaction between stellar dust disks and the planets that shape them. She is now one of the world’s experts in predicting planet size and position from the features of a star’s dust ring.
Quillen used new images from the Hubble Space Telescope that caught the star, Fomalhaut, and its surrounding ring almost edge-on and in more detail than ever before. Fomalhaut, 25 light-years away, is the brightest star in the autumn sky. Using a device called a coronagraph that blocks out a star’s light so dimmer objects near it can be seen, the Hubble revealed that Fomalhaut was indeed off-center within its ring. The images were also clear enough to show that the ring itself had a surprisingly sharp edge.
That sharp edge was the clue Quillen was looking for. Since ascertaining one of the first extra-solar planets using dust-ring analysis in 2002, Quillen has greatly strengthened her planet-ring interaction models. Treating the ring like a hydrodynamic structure, for instance, is necessary for younger stars whose dust is relatively fine and acts more like a fluid—while the physics of dust collision become dominant in older ring systems where the dust has begun clumping into larger bodies.
The sharp inside edge of Fomalhaut, Quillen calculated, demanded that a relatively small, Neptune-size planet was tucked right up against the inner side of the ring, using its gravity to toss dust in the area out of orbit.
According to Quillen’s calculations, the ring is elliptical because the Neptunian planet’s own orbit around Fomalhaut is elliptical—a curiosity in such a young system. When stars form from a giant cloud of gas and dust, the angular momentum of the cloud carries over to all the objects that form from the cloud, including new planets. Those new planets should, initially at least, orbit in nice, circular paths—not elliptical ones. Fomalhaut’s ring is offset by 1.4 billion miles, more than 15 times the distance from the Earth to the Sun, suggesting the hidden planet’s orbit is also tremendously skewed.
“Something had to skew that planet, and that’s what we’re working on now,” says Quillen. “There may have been fantastic planetary collisions early on that changed their orbits. We’re working on figuring out how many more planets of what size you’d need to account for that elliptical orbit, and to account for why there is no other dust inside that ring.”
Quillen’s model will remain just a theory until a new generation of telescopes can actually see the Formalhaut planets in question. These telescopes will be equipped with sophisticated coronagraphs that can block out Formalhaut’s light enough to let the planets themselves shine through.
Victoria Crater at Meridiani Planum June 13, 2007Posted by jtintle in Planets, Space Fotos.
Tags: HiRISE, JPL, Mars, Mars Exploration Rover Opportunity, Mars Reconnaissance Orbiter (MRO), Meridiani Planum, NASA, University of Arizona, Victoria Crater
NASA/JPL/University of Arizona
Since January, 2004, the Mars Exploration Rover Opportunity has been operating at Meridiani Planum. Five days before this image was taken, Opportunity arrived at the rim of Victoria Crater, after a drive of more than 9 km (over 5 miles). The rover can be seen in this image, at roughly the “ten o’clock” position along the rim of the crater.
Zoom-in on Venus’ oxygen airglow June 13, 2007Posted by jtintle in Planets, Space Fotos.
Tags: ESA, INAF-IASF, Obs. de Paris-LESIA, Venus, Venus Express, VIRTIS
ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA
This false-colour view was obtained on 26 August 2006 by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) onboard ESA’s Venus Express, at a distance of 65 000 kilometres from Venus’ surface, from the south. The horizon seen at the bottom-right in both panels is about Venus’ equator. The top left of the images is located at about 60 degrees south latitude; the images centre is at 130 degrees west longitude.
Both panels show the oxygen airglow in the night-side atmosphere of Venus, fully detectable only at specific infrared wavelengths. The images are built by a combination of colours: the airglow is blue, corresponding to 1.27 micrometres; yellow corresponds to 1.7 micrometres, and its modulation is due to the different cloud thickness in different areas.
On the right panel the airglow appears in atmospheric structures similar to ‘clouds’. In the left image a slightly different colour scale has been used to emphasize the brightening of the limb (side view of the atmosphere) due to the airglow itself.
The fluorescence of the airglow is produced when oxygen atoms, ‘migrating’ from the day-side to the night-side of the atmosphere of Venus under the push of the so-called sub-solar and anti-solar atmospheric circulation, recombine into molecular oxygen (or ‘O2’) emitting light.
Shuttle Plume June 12, 2007Posted by jtintle in Planets, Space Fotos.
Tags: International Space Station, Ken Thornsley, NASA, Space Shuttle Atlantis, STS-117, Vehicle Assembly Building
NASA, Ken Thornsley
What kind of cloud is that? Not a naturally occurring one. Pictured above is the drifting smoke plume left over from last Friday’s launch of the Space Shuttle Atlantis. The twisted plume was captured shortly after launch high above NASA’s massive Vehicle Assembly Building, the largest single story building in the world. Rockets frequently create picturesque plumes during launch. The Space Shuttle is currently visiting the International Space Station and delivering a new backbone truss segment to the continually developing and occupied spaceport. This trip, officially labeled STS-117, is the 118th space shuttle flight overall and the 28th for the Atlantis Orbiter.
NASA’s Chandra Sees Brightest Supernova Ever June 3, 2007Posted by jtintle in Deep Space, Space Fotos.
Tags: artist's illustration, C. Hansen, Chandra X-ray Observatory, J. Bloom, Lick Observatory, M. Weiss, N. Smith, NASA, NGC 1260, SN 2006gy, Unversity of California - Berkeley, white dwarf star
According to observations by NASA’s Chandra X-ray Observatory and ground-based optical telescopes, the supernova SN 2006gy is the brightest and most energetic stellar explosion ever recorded and may be a long-sought new type of explosion. The top panel of this graphic is an artist’s illustration that shows what SN 2006gy may have looked like if viewed at a close distance. The fireworks-like material in white shows the explosion of an extremely massive star. This debris is pushing back two lobes of cool, red gas that were expelled in a large eruption from the star before it exploded. The green, blue and yellow regions in these lobes shows where gas is being heated in a shock front as the explosion material crashes into it and pushes it backwards. Most of the optical light generated by the supernova is thought to come from debris that has been heated by radioactivity, but some likely comes from the shocked gas.
The bottom left panel is an infrared image, using adaptive optics at the Lick Observatory, of NGC 1260, the galaxy containing SN 2006gy. The dimmer source to the lower left in that panel is the center of NGC 1260, while the much brighter source to the upper right is SN 2006gy. The panel to the right shows Chandra’s X-ray image of the same field of view, again showing the nucleus of NGC 1260 and SN 2006gy. The Chandra observation allowed astronomers to determine that SN 2006gy was indeed caused by the collapse of an extremely massive star, and not the most likely alternative explanation for the explosion, the destruction of a low-mass star. If the supernova was caused by a white dwarf star exploding into a dense, hydrogen-rich environment, SN 2006gy would have been about 1,000 times brighter in X-rays than what Chandra detected.