Galactic center in unprecedented detail.Credit for Hubble image: NASA, ESA, and Q.D. Wang (University of Massachusetts, Amherst)
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Two of the biggest space telescopes have combined forces to create a HUGE panorama of the center of the Milky Way galaxy. This sweeping, composite color panorama is the sharpest infrared picture ever made of the Galactic core. Revealed in the image are a new population of massive stars and new details of complex structures in the hot gas and dust swirling around, created by solar winds and supernova explosions. The image shows an area about 300 light-years across. Click here for options in seeing this image in small, medium or super-sized extra large resolution! Click here for a stunning movie showing the location and more detail of this image in visible light. Astronomers at the American Astronomical Society meeting pointed out the actual galactic center is in the large white region near the lower right side of the image. If you need something to keep you occupied for awhile, try counting the number of stars in this image!
More about this image…
This image provides insight into how massive stars form and influence their environment in the often violent nuclear regions of other galaxies. This view combines the sharp imaging of the Hubble Space Telescope’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) with color imagery from a previous Spitzer Space Telescope survey done with its Infrared Astronomy Camera (IRAC). The Galactic core is obscured in visible light by intervening dust clouds, but infrared light penetrates the dust. The spatial resolution of NICMOS corresponds to 0.025 light-years at the distance of the galactic core of 26,000 light-years. Hubble reveals details in objects as small as 20 times the size of our own solar system. The NICMOS images were taken between February 22 and June 5, 2008.
Ganymede is about to hide behind Jupiter. Credit: NASA, ESA, and E. Karkoschka (University of Arizona)
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NASA’s Hubble Space Telescope has caught Jupiter’s moon Ganymede playing a game of hide-and-seek. In this crisp Hubble image, Ganymede is shown just before it hides behind the giant planet. Images like this one are not only gorgeous and enjoyable to look at, but are also useful for studying Jupiter’s upper atmosphere. As Ganymede passes behind the giant planet, it reflects sunlight, which then passes through Jupiter’s atmosphere. Imprinted on that light is information about the gas giant’s atmosphere, which yields clues about the properties of Jupiter’s high-altitude haze above the cloud tops. And because Hubble’s view is so sharp, we can learn more about Ganymede as well. Visible are several features on the moon’s surface, most notably the white impact crater, Tros, and its system of rays, bright streaks of material blasted from the crater. Tros and its ray system are roughly the width of Arizona. Hubble has amazing eyesight!
Composed of rock and ice, Ganymede is the largest moon in our solar system. It is even larger than the planet Mercury. But Ganymede looks like a dirty snowball next to Jupiter, the largest planet in our solar system. Jupiter is so big that only part of its Southern Hemisphere can be seen in this image.
Ganymede completes an orbit around Jupiter every seven days. Because Ganymede’s orbit is tilted nearly edge-on to Earth, it routinely can be seen passing in front of and disappearing behind its giant host, only to reemerge later.
The image also shows Jupiter’s Great Red Spot, the large eye-shaped feature at upper left. A storm the size of two Earths, the Great Red Spot has been raging for more than 300 years. Hubble’s sharp view of the gas giant planet also reveals the texture of the clouds in the Jovian atmosphere as well as various other storms and vortices.
This color image was made from three images taken on April 9, 2007, with the Wide Field Planetary Camera 2 in red, green, and blue filters. The image shows Jupiter and Ganymede in close to natural colors.
Artist's impression of a transiting exoplanet (ESA - C.Carreau)
[/caption]The Hubble Space Telescope has detected carbon dioxide on a planet orbiting another star. The star in question is HD 189733 (also known as V452 Vulpeculae, a variable star designation), a binary system over 60 light years away, and the planet is approximately the size of Jupiter (called HD 189733b). The exoplanet is already known to contain water and methane molecules from previous Hubble and Spitzer campaigns, but this is the first time CO2 has been discovered.
But why all the fuss? CO2 is another chemical marker for the existance of life. But HD 189733b isn’t a candidate planet for the search for life. After all, this “hot Jupiter” will not be hospitable to the development of even the most basic lifeforms (life as we know it in any case). This discovery is ground-breaking in that CO2can be sensed on a planet many light years from Earth…
“The carbon dioxide is kind of the main focus of the excitement, because that is a molecule that under the right circumstances could have a connection to biological activity as it does on Earth,” said Mark Swain of NASA’s Jet Propulsion Laboratory. “The very fact that we’re able to detect it, and estimate its abundance, is significant for the long-term effort of characterizing planets both to find out what they’re made of and to find out if they could be a possible host for life.”
Indeed, it wasn’t only carbon dioxide that was found; carbon monoxide was also detected in the exoplanet’s atmosphere. But the fact that CO2 is a “tracer” for life and it has been detected on a planet other than a planet known to contain life (Earth) is incredibly significant. As time goes on, observation techniques advance, it is hoped small rocky bodies will be observed. If this can be done, an Earth-like planetary survey can be carried out.
Earth atmospheric molecules detected by Venus Express (ESA)In fact, ESA’s Venus Express was recently used to characterize what Earth looks like from a distant vantage point, providing astronomers and future extraterrestrial hunters with a model that can be used when observing distant star systems. If a planet, with a similar chemical composition to that of the Earth is discovered, it would become a prime candidate for harbouring alien life.
So how did Hubble detect CO2 on HD 189733b? Through a spectroscopic analysis of the infrared radiation being emitted by the hot planet, Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) spotted an abundance of CO and CO2. Certain molecules in the exoplanet’s atmosphere absorb certain wavelengths of infrared light, leaving a spectroscopic “fingerprint” in the light detected by Hubble.
This kind of campaign is best carried out on star systems with their ecliptic plane seen edge-on to the Earth. This means the orbit of the exoplanet carries it behind the parent star and then infront of it. HD 189733b transits (or eclipses) its parent star every 2.2 days and then orbits behind the star. This is an ideal situation as astronomers are able to measure the emission from the star (when the line of sight to the exoplanet is blocked by the star) and use those measurements to subtract from spectroscopic analysis of the exoplanet. This technique isolates the exoplanet emission making it possible to analyse the chemical composition of its “day-side” atmosphere.
“We’re starting to find the molecules and to figure out how many of them there are to see the changes between the day side and the night side,” Swain said.
All these developments by Hubble will aid the future of exoplanet studies. In 2013, NASA’s James Webb Space Telescope will be launched to look out for “super-Earth” exoplanets (i.e. rocky planets larger than Earth), observing in near-infrared wavelengths. Therefore, the carbon dioxide discovery in the atmosphere of HD 189733b helps astronomers refine techniques to detect yet another tracer for life…
The hundreds of thousands of stars orbiting inside the globular cluster M13 (HST/NASA)
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This image is one of the latest views from the Hubble Space Telescope, closely resembling a toy snow globe. In this case, over a hundred thousand glittering stars are the little faux snow flakes and the cluster’s globular structure is the glass sides. The cluster of interest is M13, located over 25,000 light years away, measuring 150 light years across (that’s 0.15% the diameter of our galaxy). Although very pretty (and very festive), there are some interesting things going on inside this little cluster of stars…
Yoda imparts his wisdom to Luke in Star Wars: The Empire Strikes Back. Globular clusters impart their wisdom to astronomers. Well, the connection was there for me anyway...Globular clusters are very common, and many are known to surround our Milky Way galaxy. Over 150 ‘small’ clusters have been observed in our galaxy’s halo acting like cosmic artefacts; the stars contained within clusters like M13 are thought to be amongst the oldest known in the Universe. These clusters in the Milky Way halo are thought to have formed well before any stars existed in today’s Milky Way spiral disk. So these small, old clusters have some wisdom to impart on today’s astronomers as to the ancient history of our galaxy (why does Yoda from Star Wars spring to mind?).
The stars within M13 are predominantly old red giants that have expanded well beyond their original diameters and cooled significantly. These stars are stuck, gravitationally bound, orbiting a common point in the centre of the cluster’s mass. However, occasionally, as the centre of M13 is so densely packed, the old stars can stray too close, colliding, and creating a new type of star known as a “blue straggler”.
Blue stragglers appear off the main sequence of the Hertzsprung-Russell diagram (source)Blue stragglers are formed when the gas from one star is siphoned off by another. This rejuvenates one of the stars, heating it up significantly. This phenomenon has mystified astronomers for a long time as young, blue stars were observed hiding inside clusters of old, red stars. Only recently has this collision mechanism been put forward as a possible explanation to the appearance of “young”, hot stars inside globular clusters like M13.
Putting snow globes, Yoda and blue stragglers to one side, the stunning image at the top of this post comprises of several archival observations from Hubble’s Wide Field Planetary Camera 2 and Advanced Camera for Surveys. Four separate campaigns from November 1999, April 2000, August 2005 and April 2006 were used.
What a great picture to start getting into the Christmas holiday spirit with…
NASA announced Thursday that space shuttle Atlantis’ STS-125 mission to repair the Hubble Space Telescope is targeted to launch May 12, 2009. The mission, which was previously scheduled for October of this year was delayed when a data handling unit on the telescope failed. Since then, engineers have been working to prepare a 1970’s era spare unit for flight. They expect to be able to ship the spare, known as the Science Instrument Command and Data Handling System, to NASA’s Kennedy Space Center in Florida in spring 2009.
STS-125 is an 11-day flight featuring five spacewalks to extend Hubble’s life into the next decade by refurbishing and upgrading the telescope with state-of-the-art science instruments and swapping failed hardware. The crew consists of Scott Altman, commander; Greg Johnson, pilot; and mission specialists are veteran spacewalkers John Grunsfeld and Mike Massimino, and first-time space fliers Andrew Feustel, Michael Good and Megan McArthur.
The next space shuttle mission, STS-119, is scheduled for launch on Feb. 12, 2009, which will go to the International Space Station and bring up the S6 starboard truss segment and the final set of solar arrays. Another shuttle mission, STS-127 mission, is also targeted for launch in May 2009, but it’s possible that flight could slip. The Hubble mission will need another shuttle on standby for a rescue mission, should STS-125 encounter any problems (since its not going to the ISS, which would serve as a safe haven if a shuttle had any damage where it could not land safely).
Beyond that, STS-128 is targeted for August 2009, and STS-129 is targeted for November 2009. As always, all target launch dates are subject to change.
WR 25 and Tr16-244 Credits: NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain)
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The Carina Nebula contains the famous blue star Eta Carinae, which has the highest luminosity of any star we know. And in the same nebula live two other life-in-the-fastlane stars, and the Hubble Space Telescope has provided this gorgeous, gorgeous image of them. Until recently these colossal stars — two of our galaxy’s most massive luminaries — have been shrouded in mystery, (avoiding the paparazzi, no doubt). But Hubble’s Wide Field Camera has done what only HST’s investigative reporting could unveil, revealing these stars greater detail than ever before. These stars are so bright and powerful that they burn through their hydrogen fuel source faster than other types of stars, leading to a ‘live fast, die young’ stellar lifestyle. And (gasp!) one of the stars has been hiding a secret companion, and (double gasp!) the other star is part of a three-some! Is that why this nebula is giving these stars “the finger?”
The two stars WR 25 and Tr16-244, located within the open cluster Trumpler 16, is embedded within an immense cauldron of gas and dust that lies approximately 7,500 light-years from Earth. They produce incredible amounts of heat, emitting most of their radiation in the ultraviolet and appearing blue in color.
WR 25 is the brightest, situated near the centre of the image. The neighboring Tr16-244 is the third brightest, just to the upper left of WR 25. The second brightest, to the left of WR 25, is a low-mass star located much closer to Earth than the Carina Nebula.
WR 25 is likely to be the most massive and interesting of the two. Its true nature was revealed two years ago when an international group of astronomers led by Roberto Gamen, then at the Universidad de La Serena in Chile, discovered that it is composed of at least two stars.
It’s not usual for massive stars to form in compact clusters, and often, the individual stars are physically so close to each other that it is very difficult to resolve them in telescopes as separate objects. And now, these Hubble observations have revealed that the Tr16-244 system is actually a triple star. (see image below).
WR 25 and Tr16-244 are the likely sources of radiation that is causing a giant gas globule within the Carina Nebula to slowly evaporate away into space, while possibly inducing the formation of new stars within it (see separate image). The radiation is also thought to be responsible for the globule’s interesting shape, prominently featured in earlier Hubble images, which looks like a hand with a ‘defiant’ finger pointing towards WR 25 and Tr16-244.
And if you can’t see it, here’s more detail of “the finger.” Carina nebula detail from HST.
NCG 1569. Image Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and A. Aloisi (STScI/ESA)
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Astronomers have long wondered why a small, nearby, isolated galaxy is pumping out new stars faster than any galaxy in our local neighborhood. Usually, galaxies need some sort of gravitational interaction with other galaxies to trigger star formation, and galaxy NGC 1569 appeared to be a loner, far away from other galaxies, but churning out new stars like crazy. Now, a new look at the galaxy with the Hubble Space Telescope shows the galaxy is farther away than originally thought, which places NCG 1569 in the middle of a group of about 10 galaxies. Gravitational interactions among the group’s galaxies may be compressing gas in NGC 1569 and igniting the star-birthing frenzy.
“Now the starburst activity seen in NGC 1569 makes sense, because the galaxy is probably interacting with other galaxies in the group,” said the study’s leader, Alessandra Aloisi of the Space Telescope Science Institute in Baltimore, Md., and the European Space Agency. “Those interactions are probably fueling the star birth.”
The farther distance not only means that the galaxy is intrinsically brighter, but also that it is producing stars two times faster than first thought. The galaxy is forming stars at a rate more than 100 times higher than the rate in the Milky Way. This high star-formation rate has been almost continuous for the past 100 million years.
Discovered by William Herschel in 1788, NGC 1569 is home to three of the most massive star clusters ever discovered in the local universe. Each cluster contains more than a million stars.
“This is a prime example of the type of massive starbursts that drive the evolution of galaxies in the distant and young universe,” said team member Roeland van der Marel of the Space Telescope Science Institute. “Starburst galaxies can only be studied in detail in the nearby universe, where they are much rarer. Hubble observations of our galactic neighborhood, including this study, are helping astronomers put together a complete picture of the galaxies in our local universe. Put the puzzle pieces in the right place, as for NGC 1569, and the picture makes much more sense.”
And besides all that, it’s just a pretty picture, too!
Hubble and its most recent science image. Credit: NASA
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The space shuttle mission to repair and update the Hubble Space Telescope has been delayed. Mission managers were aiming for a February 2009 launch for STS-125 flight for the fifth and final shuttle mission to the Hubble Space Telescope. The replacement component for the data handling system that recently caused problems for the telescope not be ready by February, and now NASA is looking for a May 2009 launch. On a positive note, the “other” shuttle mission waiting in the wings, STS-126 to the International Space Station, is looking good and is go for launch. Current launch date is set for November 14 at 7:55 p.m. EST.
“We now have done enough analysis of all the things that need to happen with the flight spare unit to know that we cannot be ready for a February launch,” said NASA’s Astrophysics Division Director Jon Morse at NASA Headquarters in Washington. The spare Science Instrument Command and Data Handling system unit will replace one that failed on Hubble in late September, causing the agency to postpone the servicing mission, which had been targeted for Oct. 14.
A significant anomaly occurred during testing of the unit and NASA says six and a half months of further testing is needed before the it can be certified to fly. NASA’s plan is to have the spare unit ready to ship in the April 2009 timeframe so as to support a May 2009 launch. sts-126 mission. Credit: NASA
Endeavour’s STS-126 flight, set to launch on November 14 will feature important repair work to the station and prepare it for housing six crew members during long-duration missions. The primary focus of the 15-day flight and its four planned spacewalks is to service the station’s two Solar Alpha Rotary Joints, which have not been working correctly. They allow the station’s solar arrays to track the sun. Endeavour will carry about 32,000 pounds to orbit, including supplies and equipment necessary to double the crew size from three to six members in spring 2009. The new station cargo includes additional sleeping quarters, a second toilet and a resistance exercise device.
Interacting Galaxies Arp 147. Credit: NASA, ESA, and M. Livio (STScI)
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Yes! (*Fist pump*) The Hubble Space Telescope is back in business.
After overcoming a few glitches in bringing the orbiting Hubble back online, engineers and scientists aimed the telescope’s prime camera, the Wide Field Planetary Camera 2 (WFPC2), at a pair of gorgeous-looking interacting galaxies called Arp 147. Scientists say the image demonstrates the camera is working exactly as it was before going offline, thereby scoring a “perfect 10” both for performance and beauty. And the two galaxies are oriented so they look like the number 10! How cool is that!
Two anomalies in Hubble’s restart caused the B-side of the Science Instrument Control and Data Handling System (SI C&DH-B) and the Advanced Camera for Surveys (ACS) Solar Blind Channel (SBC) to return to a ‘safe hold’ status on October 16. Engineers worked through the problem, and on Oct. 25, the telescope’s science computer began to send commands to the WFPC2. What a relief!
Additional commanding allowed engineers on the ground to assess the instrument’s state of health and verify the contents of the camera’s microprocessor memory.
And so, this first “post-recovery” image shows the two interacting galaxies. The left-most galaxy, or the “one” in this image, is relatively undisturbed apart from a smooth ring of starlight. It appears nearly on edge to our line of sight. The right-most galaxy, resembling a zero, exhibits a clumpy, blue ring of intense star formation.
The blue ring was most probably formed after the galaxy on the left passed through the galaxy on the right. Just as a pebble thrown into a pond creates an outwardly moving circular wave, a propagating density wave was generated at the point of impact and spread outward. As this density wave collided with material in the target galaxy that was moving inward due to the gravitational pull of the two galaxies, shocks and dense gas were produced, stimulating star formation.
The dusty reddish knot at the lower left of the blue ring probably marks the location of the original nucleus of the galaxy that was hit.
Arp 147 appears in the Arp Atlas of Peculiar Galaxies, compiled by Halton Arp in the 1960s and published in 1966. This picture was assembled from WFPC2 images taken with three separate filters. The blue, visible-light, and infrared filters are represented by the colors blue, green, and red, respectively.
The galaxy pair was photographed on October 27-28, 2008. Arp 147 lies in the constellation Cetus, and it is more than 400 million light-years away from Earth.
Engineers look on in the Space Telescope Operations Control Center as commands are sent to the SIC and DH. Credit: NASA
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So far, everything is going well and as planned for the Hubble Space Telescope’s long-distance ‘brain surgery.’ During the night of Oct. 15, Space Telescope Operations Control Center engineers at NASA’s Goddard Space Flight Center successfully turned on and checked out Side B of Hubble’s Science Instrument Control and Data Handling (SIC&DH) system. Engineers were then able to retrieve the Advanced Camera for Surveys (ACS), Wide Field Planetary Camera 2 (WFPC2) and Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instruments. They were being held in safe mode, and were turned on, each showing they had a working interface to the Side B of SIC&DH. The instruments were then commanded back into safe mode, and then at noon today commands will be sent from Side B to each of the instruments. Engineers will then begin calibrations of the telescope’s science instruments, which they hope to finish before midnight Thursday. So this is good news…
The primary data handling system, Side A, had been used exclusively since HST launched in 1991. It failed two weeks ago. While engineers believed the redundant Side B – which hadn’t been turned on for over 18 years – would work, nothing was certain.
Scientists at the Space Telescope Science Institute in Baltimore should complete the check-out of all the instruments by noon on Friday, October 17. They will collecting and compare baseline exposures previously taken using Side A to new exposures, using by Side B. If everything looks good, everyone is hoping normal science observations will resume early Friday morning.
