NASA's Hubble Space Telescope has discovered 16 extrasolar planet candidates orbiting a variety of distant stars in the central region of our Milky Way galaxy.
The planet bonanza was uncovered during a Hubble survey, called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Hubble looked farther than has ever successfully been searched for extrasolar planets. Hubble peered at 180,000 stars in the crowded central bulge of our galaxy 26,000 light-years away or one-quarter the diameter of the Milky Way's spiral disk. The results will appear in the Oct. 5 issue of the journal Nature.
Hubble Finds First Organic Molecule on an Exoplanet
NASA's Hubble Space Telescope has made the first detection ever of an organic molecule in the atmosphere of a Jupiter-sized planet orbiting another star. This breakthrough is an important step in eventually identifying signs of life on a planet outside our solar system. The molecule found by Hubble is methane, which under the right circumstances can play a key role in prebiotic chemistry - the chemical reactions considered necessary to form life as we know it. This illustration depicts the extrasolar planet HD 189733b with its parent star peeking above its top edge.
In 19 years of observations, the Hubble Space Telescope has amassed a huge archive of data. That archive may contain the telltale glow of undiscovered extrasolar planets, says David Lafrenière of the University of Toronto, Ontario, Canada. His team found the outermost of three massive planets known to orbit the young star HR 8799, which is 130 light-years away. The planetary trio was originally discovered in images taken with the Keck and Gemini North telescopes in 2007 and 2008. But using a new image processing technique that suppresses the glare of the parent star, Lafrenière found the telltale glow of the outermost planet in the system while studying Hubble archival data taken in 1998. The giant planet is young and hot, but still only 1/100,000th the brightness of its parent star (by comparison, cooler Jupiter is one-billionth the brightness of the sun).
Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has looked at over 200 other stars in coronagraphic mode, where the light of the star is largely blocked out, to search for the feeble glow of planets. Lafrenière plans to look for undiscovered planets in the NICMOS archive dataset and do follow-up observations with ground-based telescopes on any candidates that pop up. As an added bonus, NICMOS made a near-infrared measurement that suggests water vapor is in the atmosphere of the planet. This could not be easily achieved with ground-based telescopes, because water vapor in Earth's atmosphere absorbs some infrared wavelengths. Measuring the water absorption properties on this exoplanet will tell astronomers a great deal about the temperatures and pressures in the atmosphere, and about the prevalence of dust clouds. But don't go looking for beachfront property; the planet is 1,500 degrees Fahrenheit -- too hot even for water vapor clouds.
"The Star That Ate My Planet" may sound like a B-grade science fiction movie title, but this is really happening 600 light-years away. Like a moth in a candle flame, a doomed Jupiter-sized planet has moved so close to its sunlike parent star that it is spilling its atmosphere onto the star. This happens because the planet gets so hot that its atmosphere puffs up to the point where the star's gravity pulls it in. The planet will likely be completely devoured in 10 million years. Observations by Hubble's new Cosmic Origins Spectrograph measured a variety of elements in the planet's bloated atmosphere as the planet passed in front of its star. The planet, called WASP-12b, is the hottest known world ever discovered, with an atmosphere seething at 2,800 degrees Fahrenheit.
Out of Whack Planetary System Offers Clues to a Disturbed Past
For just over a decade, astronomers have known that three Jupiter-type planets orbit the yellow-white star Upsilon Andromedae. But to their surprise it's now been discovered that not all planets orbit this star in the same plane, as the major planets in our solar system orbit the Sun. The orbits of two of the planets are inclined by 30 degrees with respect to each other. Such a strange orientation has never before been seen in any other planetary system. This surprising finding will impact theories of how planetary systems form and evolve, say researchers. It suggests that some violent events can happen to disrupt planets' orbits after a planetary system forms. The discovery was made by joint observations with the Hubble Space Telescope, the giant Hobby-Eberly Telescope, and other ground-based telescopes.
These findings were presented in a press conference today at the 216th meeting of the American Astronomical Society in Miami.
As if the debate over what is and what is not a planet hasn't gotten confusing enough, Hubble Space Telescope astronomers have now confirmed the existence of a tortured, baked object that could be called a "cometary planet." The gas giant planet, dubbed HD 209458b, is orbiting so close to its star that its heated atmosphere is escaping away into space. Now, observations by the new Cosmic Origins Spectrograph (COS) aboard NASA's Hubble suggest that powerful stellar winds are sweeping the castoff material behind the scorched planet and shaping it into a comet-like tail.
This artist's illustration shows a view of HD 209458b, as seen from the surface of a hypothetical nearby companion object.
NASA's Hubble Finds Rare Blue Straggler Stars in the Milky Way's Hub
Peering deep into the star-filled, ancient hub of our Milky Way (left), NASA's Hubble Space Telescope has found a rare class of oddball stars called blue stragglers. This is the first time such objects have been detected within our galaxy's bulge. Blue stragglers are so named because they seem to be lagging behind in their rate of aging compared with nearby older stars.
The discovery is a spin-off from a seven-day-long survey conducted in 2006 called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Hubble peered at and obtained variability information for 180,000 stars in the crowded central bulge of our galaxy, 26,000 light-years away.
NASA's Hubble Makes One Millionth Science Observation
NASA's Hubble Space Telescope crossed another milestone in its 21-year space odyssey of exploration and discovery. On Monday, July 4, the Earth-orbiting observatory logged its one millionth science observation during a search for water in an exoplanet's atmosphere 1,000 light-years away. Although Hubble is best known for its stunning imagery of the cosmos, the millionth exposure is a spectroscopic measurement, where light is divided into its component colors. These color patterns can reveal the chemical composition of cosmic sources. This is an artist's concept of Hubble's millionth exposure, the extrasolar planet HAT-P-7b. It is a gas planet larger than Jupiter orbiting a star hotter than our Sun. HAT-P-7b, also known as Kepler 2b, has been studied by NASA's planet-hunting Kepler observatory after it was discovered by ground-based observations.
Neptune Completes Its First Circuit Around The Sun Since Its Discovery
These four images of Neptune were taken by NASA's Hubble Space Telescope during the planet's 16-hour rotation. The snapshots were taken at roughly four-hour intervals, offering a full view of the blue-green planet. Today marks Neptune's first orbit around the Sun since it was discovered nearly 165 years ago. These images were taken to commemorate the event.
The Hubble images, taken with the Wide Field Camera 3 on June 25-26, reveal high-altitude clouds in the northern and southern hemispheres. The clouds are composed of methane ice crystals. In the Hubble images, absorption of red light by methane in Neptune's atmosphere gives the planet its distinctive aqua color. The clouds look pink because they are reflecting near-infrared light. A faint, dark band near the bottom of the southern hemisphere is probably caused by a decrease in the hazes in the atmosphere that scatter blue light. The band was imaged by NASA's Voyager 2 spacecraft in 1989, and may be tied to circumpolar circulation created by high-velocity winds in that region. Neptune is the most distant major planet in our solar system. German astronomer Johann Galle discovered the planet on September 23, 1846. At the time, the discovery doubled the size of the known solar system. The planet is 2.8 billion miles (4.5 billion kilometers) from the Sun, 30 times farther than Earth. Under the Sun's weak pull at that distance, Neptune plods along in its huge orbit, slowly completing one revolution approximately every 165 years.
The long-term forecast for the Milky Way is cloudy with gaseous rain. A study by Nicolas Lehner and Christopher Howk of the University of Notre Dame concludes that massive clouds of ionized gas are raining down from our galaxy's halo and intergalactic space and will continue to provide fuel for the Milky Way to keep forming stars. Using the Hubble Space Telescope's Cosmic Origins Spectrograph they measured for the first time the distances to huge, fast-moving clouds of ionized gas previously seen covering a large fraction of the sky.
Astronomers Find Elusive Planets in Decade-Old Hubble Data
In a painstaking re-analysis of Hubble Space Telescope images from 1998, astronomers have found visual evidence for two extrasolar planets that went undetected back then.
Finding these hidden gems in the Hubble archive gives astronomers an invaluable time machine for comparing much earlier planet orbital motion data to more recent observations. It also demonstrates a novel approach for planet hunting in archival Hubble data.
The Milky Way Contains at Least 100 Billion Planets According to Survey
Our Milky Way galaxy contains a minimum of 100 billion planets according to a detailed statistical study based on the detection of three extrasolar planets by an observational technique called microlensing.
Kailash Sahu, of the Space Telescope Science Institute in Baltimore, Md., is part of an international team reporting today that our galaxy contains a minimum of one planet for every star on average. This means that there is likely to be a minimum of 1,500 planets within just 50 light-years of Earth.
NASA's Hubble Reveals a New Class of Extrasolar Planet
Observations of the extrasolar planet GJ1214b by NASA's Hubble Space Telescope have come up with a new class of planet, a waterworld enshrouded by a thick, steamy atmosphere. It's smaller than Uranus but larger than Earth. A paper reporting these results has been accepted for publication in The Astrophysical Journal and is available online.
Hubble, Swift Detect First-Ever Changes in an Exoplanet Atmosphere
An international team of astronomers using data from the NASA's Hubble Space Telescope has made an unparalleled observation, detecting significant changes in the atmosphere of a planet located beyond the solar system. The scientists conclude that the atmospheric variations occurred in response to a powerful eruption on the planet's host star, an event observed by NASA's Swift satellite. This artist's rendering illustrates the evaporation of exoplanet HD 189733b's atmosphere in response to the powerful eruption from its host star on Sept. 7, 2011. Hubble detected the escaping gases, and Swift caught the stellar flare.
Hubble Reveals Rogue Planetary Orbit for Fomalhaut b
Newly released Hubble Space Telescope images of a vast debris disk encircling the nearby star Fomalhaut, and of a mysterious planet circling it, may provide forensic evidence of a titanic planetary disruption in the system. Astronomers are surprised to find that the debris belt is wider than previously known, spanning a gulf of space from 14 billion miles to nearly 20 billion miles from the star. Even more surprisingly, the latest Hubble images have allowed a team of astronomers to calculate that the planet follows an unusual elliptical orbit that carries it on a potentially destructive path through the vast dust ring.
The planet, called Fomalhaut b, swings as close to its star as 4.6 billion miles, and the outermost point of its orbit is 27 billion miles away from the star. The orbit was re-calculated from the newest Hubble observation made in 2012. The Fomalhaut team led by Paul Kalas (University of California, Berkeley) considers this circumstantial evidence that there may be other planet-like bodies in the system that gravitationally disrupted Fomalhaut b to place it in such a highly eccentric orbit. His team is presenting their finding today at the 221st meeting of the American Astronomical Society in Long Beach, Calif.
Rare Stellar Alignment Offers Opportunity to Hunt for Planets
The ancients thought that stars were fixed pinpoints of light on the sky. Today we know that they are all moving, like fish in a pond. This so-called proper motion is so small that it is not noticeable to the human eye over a single lifetime. But Hubble can precisely track stellar motions to razor-sharp precision. Not surprisingly the nearest star to our Sun, Proxima Centauri, is one of the fastest moving across the sky. Hubble astronomers have found that it will pass in front of two far-more distant background stars, once in 2014 and again in 2016. This will afford a very rare opportunity to see how Proxima's gravity warps the image of the background stars by bending their light. This effect, called gravitational lensing, can be used to estimate Proxima Centauri's mass and establish the presence of any planets orbiting the star.
Hubble has identified the true visible-light color of a giant Jupiter-sized planet located 63 light-years away. The planet has a cobalt blue color. It has torrential 4,500-mile-per-hour winds that are so hot they melt silicates into raindrops of molten glass. And that's where the cobalt-blue hue comes from, not oceans. The glass droplets scatter blue light more readily than green or red light.
The planet's color provides unique clues to the atmosphere and weather on a truly alien world that orbits much closer to its star than the innermost planet Mercury is to our Sun.
Water-rich Planetary Building Blocks Found Around White Dwarf
If you go walking along the beach or take an ocean cruise, it's hard to believe that Earth is essentially a "dry" planet. Barely 0.02 percent of our home planet's mass is surface water. In fact, our oceans came along a few hundred million years after Earth formed 4.6 billion years ago. Though still debated, astronomers think that the primeval Earth was most likely irrigated when water-rich asteroids in the solar system crashed into our planet.
Now astronomers have found that the same water "delivery system" could have occurred in a dying star's planetary system. Hubble Space Telescope spectroscopic observations have found forensic evidence for the same kind of water-rich asteroids that may have once brought water to Earth. Observations made with Hubble's Cosmic Origins Spectrograph (COS) allowed the team of astronomers to do a robust chemical analysis of debris falling into the white dwarf star GD 61, located 150 light-years from Earth. They didn't detect planets but the building blocks of planets. The asteroids are plummeting deep into the gravitational field of the white dwarf, presumably due to gravitational perturbations from a surviving Jupiter-sized planet in the system. This is circumstantial evidence that potentially habitable planets once existed in this star system. However, the star burned out 200 million years ago.
Hubble Traces Subtle Signals of Water on Hazy Worlds
Astronomers continue to tally up how many planets are orbiting other stars. But finding out what their atmospheres are made of is another story. Two teams of scientists using the Hubble Space Telescope have found faint signatures of water in the atmospheres of five distant exoplanets. The planets are not the size of Earth, but rather massive worlds known as hot Jupiters because they orbit so close to their stars. Hubble's instruments can deduce the types of gases in the atmospheres of these monsters by determining which colors of a star's light are transmitted and which are partially absorbed as the planet passes in front of its star. The observations demonstrate Hubble's continuing exemplary performance in exoplanet research.
Hubble Sees Cloudy Super-Worlds with Chance for More Clouds
Weather forecasters on a pair of exoplanets would have an easy job. Today's forecast: cloudy. Tomorrow: overcast. Extended outlook: more clouds. Scientists using the Hubble Space Telescope have characterized the atmospheres of two of the most common type of planets in the Milky Way galaxy and found both may be blanketed with clouds. The best guess is that the clouds are not like anything found on Earth. Their scorching atmospheres are predicted to be hundreds of degrees Fahrenheit – too hot for a rainy day.
