Hubble Photographs Another World

First Snap shots of a planet circling another star!!

Image above: Artist's concept of the star Fomalhaut and the Jupiter-type planet that the Hubble Space Telescope observed. A ring of debris appears to surround Fomalhaut as well. The planet, called Fomalhaut b, orbits the 200-million-year-old star every 872 years. Credit: ESA, NASA, and L. Calcada (ESO for STScI)

NASA's Hubble Space Telescope has taken the first visible-light snapshot of a planet circling another star.Estimated to be no more than three times Jupiter's mass, the planet, called Fomalhaut b, orbits the bright southern star Fomalhaut, located 25 light-years away in the constellation Piscis Australis, or the "Southern Fish."

Fomalhaut has been a candidate for planet hunting ever since an excess of dust was discovered around the star in the early 1980s by NASA's Infrared Astronomy Satellite, IRAS.

In 2004, the coronagraph in the High Resolution Camera on Hubble's Advanced Camera for Surveys produced the first-ever resolved visible-light image of the region around Fomalhaut. It clearly showed a ring of protoplanetary debris approximately 21.5 billion miles across and having a sharp inner edge.

This large debris disk is similar to the Kuiper Belt, which encircles the solar system and contains a range of icy bodies from dust grains to objects the size of dwarf planets, such as Pluto.

Hubble astronomer Paul Kalas, of the University of California at Berkeley, and team members proposed in 2005 that the ring was being gravitationally modified by a planet lying between the star and the ring's inner edge.

Circumstantial evidence came from Hubble's confirmation that the ring is offset from the center of the star. The sharp inner edge of the ring is also consistent with the presence of a planet that gravitationally "shepherds" ring particles. Independent researchers have subsequently reached similar conclusions.

Now, Hubble has actually photographed a point source of light lying 1.8 billion miles inside the ring's inner edge. The results are being reported in the November 14 issue of Science magazine."Our Hubble observations were incredibly demanding. Fomalhaut b is 1 billion times fainter than the star. We began this program in 2001, and our persistence finally paid off," Kalas says."

Fomalhaut is the gift that keeps on giving. Following the unexpected discovery of its dust ring, we have now found an exoplanet at a location suggested by analysis of the dust ring's shape. The lesson for exoplanet hunters is 'follow the dust,'" said team member Mark Clampin of NASA's Goddard Space Flight Center in Greenbelt, Md.

Observations taken 21 months apart by Hubble's Advanced Camera for Surveys' coronagraph show that the object is moving along a path around the star, and is therefore gravitationally bound to it. The planet is 10.7 billion miles from the star, or about 10 times the distance of the planet Saturn from our sun.

The planet is brighter than expected for an object of three Jupiter masses. One possibility is that it has a Saturn-like ring of ice and dust reflecting starlight. The ring might eventually coalesce to form moons. The ring's estimated size is comparable to the region around Jupiter and its four largest orbiting satellites.

Kalas and his team first used Hubble to photograph Fomalhaut in 2004, and made the unexpected discovery of its debris disk, which scatters Fomalhaut's starlight. At the time they noted a few bright sources in the image as planet candidates. A follow-up image in 2006 showed that one of the objects is moving through space with Fomalhaut but changed position relative to the ring since the 2004 exposure. The amount of displacement between the two exposures corresponds to an 872-year-long orbit as calculated from Kepler's laws of planetary motion.

Future observations will attempt to see the planet in infrared light and will look for evidence of water vapor clouds in the atmosphere. This would yield clues to the evolution of a comparatively newborn 100-million-year-old planet. Astrometric measurements of the planet's orbit will provide enough precision to yield an accurate mass.

NASA's James Webb Space Telescope, scheduled to launch in 2013 will be able to make coronagraphic observations of Fomalhaut in the near- and mid-infrared. Webb will be able to hunt for other planets in the system and probe the region interior to the dust ring for structures such as an inner asteroid belt.

J.D. Harrington NASA Headquarters

Ray Villard Space Telescope Science Institute

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STS-125: The Final Visit

STS-125: The Final Visit to the Hubble Space Telescope (HST)



It's a mission to once more push the boundaries of how deep in space and far back in time humanity can see. It's a flight to again upgrade what already may be the most significant satellite ever launched.



And, for the space shuttle, it's a final visit to a dear, old friend.



The STS-125 mission will return the space shuttle to the Hubble Space Telescope for one last visit before the shuttle fleet retires in 2010. Over 12 days and five spacewalks, the shuttle Atlantis’ crew will make repairs and upgrades to the telescope, leaving it better than ever and ready for another five years – or more – of research.



The shuttle Discovery launched Hubble in 1990, and released it into an orbit 350 miles above the Earth. Since then it’s circled Earth more than 97,000 times and provided more than 4,000 astronomers access to the stars not possible from inside Earth’s atmosphere. Hubble has helped answer some of science’s key questions and provided images that have awed and inspired the world.

The Hubble Space Telescope is in the grip of space shuttle Columbia's robotic arm in March 2002 at the beginning of STS-109, the third Hubble servicing mission. Image: NASA



“We’ve actually seen an object that emitted its light about 13 billion years ago,” said Hubble senior scientist Dave Leckrone. “Since the universe is 13.7 billion years old, that’s its infancy, the nursery. From the nearest parts of our solar system to further back in time than anyone has ever looked before, we’ve taken ordinary citizens on a voyage through the universe.”



But Hubble has not done it alone.



Atlantis’ crew – Commander Scott Altman, Pilot Gregory C. Johnson and Mission Specialists Andrew Feustel, Michael Good, John Grunsfeld, Mike Massimino and Megan McArthur – will be the fifth shuttle crew to fly to the telescope. Their predecessors have replaced and repaired failed and faulty components and added new and improved cameras and scientific equipment, and the STS-125 crew will be no different.



Most exciting are the new scientific instruments Atlantis’ spacewalkers will install. The Cosmic Origins Spectrograph, for instance, will observe the light put out by extremely faint, far-away quasars and see how that light changes as it passes through the intervening gas between distant galaxies. In this way scientists will learn what that gas is made of, how it’s changed over time and how it affects the galaxies around it.



“It’s an important player in the story of how galaxies are formed and how the chemical makeup of the universe has changed over time,” Leckrone said.



And the new Wide Field Camera 3 will allow Hubble to take large-scale, extremely clear and detailed pictures over a very wide range of colors. At ultraviolet and infrared wavelengths the WFC3 represents a dramatic improvement in capability over all previous Hubble cameras. It is also a very capable visible light camera, though by design not quite as capable at visible wavelengths as Hubble’s Advanced Camera for Surveys. The WFC3 and ACS are designed to work together in a complementary fashion.



“If I want a complete family album of the universe, I need to look at it in all these different wavelengths,” Leckrone said. “This will be the first time we’ve had an opportunity to take all these different images together, to have a comparable quality of pictures across this whole wavelength band.”



Before those much anticipated views are seen, though, the equipment has to be installed – a process that will be exciting in its own right. The spacewalks necessary to outfit Hubble will be very different from the spacewalks conducted at the International Space Station.



“It’s more like brain surgery than construction,” Lead Flight Director Tony Ceccacci said. “On station spacewalks, you’re installing large pieces of equipment – trusses, modules, etc. – and putting it together like an erector set. You can’t do that with Hubble. Hubble spacewalks are comparable to standing at an operating table, doing very dexterous work.”



Although the installation of the new equipment and the replacement of some old items – gyroscopes, batteries and a fine guidance sensor – will be challenging, it’s the repairs the astronauts plan that will be the most complicated.



The new camera and spectrograph are designed to complement the scientific instruments already on the telescope – specifically the Advanced Camera for Surveys and the Space Telescope Imaging Spectrograph. But pieces of those instruments have failed in past years – not the entire instrument, but specific pieces inside of them.



The crew will replace only the pieces that have failed. But those instruments were never designed to be repaired in space. In fact, they were specifically designed not to come apart.



“When we first looked at it, we were going ‘well, maybe, maybe not,’” Ceccacci said.



Since then, the team has come up with a plan for the work that Ceccacci believes will be very successful. But it won’t be easy – the repair of the spectrograph, for instance, requires the spacewalkers to remove more than 100 screws to access a computer card they will pull out and replace.



Still, the mission’s commander pointed out that it’s good practice for the future. “I think it’s a step that we need to take to make us better able to go to places like Mars,” Altman said. “You don’t want to drag a whole spare giant box along – you’d like to be able to have the one little transistor you need to plug in when that fails. Being able to demonstrate this in space is a key element of us growing as a space-faring people.”



The Hubble spacewalks won’t be the only things that differ from missions to the space station. Confined to just the shuttle, the quarters will be tighter; with five back-to-back spacewalks, the pace will be faster.



Without the station crew to give the shuttle a once over and photograph its heat shield , the customary survey of the heat shield done the day after launch will be much more intensive. The crew will use the shuttle robotic arm and its 50-foot boom extension and sensor systems to perform not only the standard nose cap and wing leading edges inspection, but also a survey of the upper crew cabin and the entire underside.



In the unlikely event that irreparable damage is found, the crew also won’t be able to get to the space station to wait for a ride home – Atlantis can't reach the station from Hubble’s orbit. Because the crew won't have access to the station and the support it could provide in an emergency, the mission to Hubble requires some changes on the ground.



For every shuttle mission since Columbia, there has been a contingency plan in place to allow another shuttle to be launched if needed to rescue a stranded shuttle crew. On station missions, that stranded crew can wait longer at the station than would be the case for Atlantis. So, for 125, another shuttle will be standing ready on Kennedy Space Center’s Launch Pad 39-B. If needed, space shuttle Endeavour, manned by the flight deck crew of mission STS-123 which flew in March, will be ready to fly to Hubble and retrieve Atlantis’ crew within days.



What puts Altman’s mind at ease, however, are the changes NASA has made to keep damage from occurring in the first place.



“I feel pretty good that we’ve made incredible improvement in the external tank,” he said. “That’s the root cause. But if something does happen, I think we have the tools to find it, see where it is, evaluate how serious it is and fix it. And then on that one-way-down-at-the-edge-of-the-probability-level chance that you could have damage such that you wouldn’t want to come home on it, we have the capability to stay up there – extend our time and have another shuttle come get us.”



The risks, he believes, are relatively small, and the payoff is huge.



“Hubble puts cutting edge science together with a visual image that grabs the public’s imagination,” Altman said. “I think that’s the first step in exploration. Because Hubble takes light that’s been traveling for billions of years, sucks it in and shows it to us. It’s like taking you on a journey 13 and a half billion light years away while you sit there at home and look out at the universe.”



Nick

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