STScI Astronomers Help Develop and Operate World's Most Powerful Planet Finder
Space Telescope Science Institute astronomers have been involved in nearly a decade of development, construction, and testing of the world's most advanced instrument for directly photographing and analyzing planets around other stars. Called the Gemini Planet Imager (GPI), the instrument will be used to photograph faint planets next to bright stars and probe their atmospheres, and to study dusty disks around young stars. GPI was used to image Beta Pictoris b, a planet orbiting the star Beta Pictoris. The bright star Beta Pictoris is hidden behind a mask in the center of the image that blocks out the glare of the central star.
Astronomers using the Hubble Space Telescope have gone looking for water vapor in the atmospheres of three planets orbiting stars similar to the Sun – and have come up nearly dry. The planets spectroscopically surveyed have only one-tenth to one one-thousandth the amount of water predicted by standard planet-formation theories. The planets are not habitable because they are gaseous and are as big as Jupiter. They lie so much closer to their host star than Jupiter is to our Sun, so their atmospheres are seething between 1,500 and 4,000 degrees Fahrenheit. Nevertheless, this result suggests that some percentage of Earth-size exoplanets may be more deficient in water than predicted. And, water is a necessary prerequisite for life as we know it. The search for water-bearing terrestrial worlds may be more challenging than thought for future space telescopes. And, scientists may have to revisit their theories of planet formation.
NASA Telescopes Find Clear Skies and Water Vapor on Exo-Neptune
The weather forecast for a planet 120 light-years from Earth is clear skies and steamy water vapor. Finding clear skies on a gaseous world the size of Neptune is a good sign that even smaller, Earth-size planets might have similarly good visibility. This would allow earthbound astronomers to measure the underlying atmospheric composition of an exoplanet. Astronomers using the Hubble, Spitzer, and Kepler space telescopes were able to determine that the planet, cataloged HAT-P-11b, has water vapor in its atmosphere. The world is definitely steamy with temperatures over 1,000 degrees Fahrenheit. The planet is so hot because it orbits so close to its star, completing one orbit every five days.
Hubble Maps the Temperature and Water Vapor on an Extreme Exoplanet
Located 260 light-years away, exoplanet WASP-43b is no place to call home. It is a world of extremes, where seething winds howl at the speed of sound from a 3,000-degree-Fahrenheit day side, hot enough to melt steel, to a pitch-black night side with plunging temperatures below 1,000 degrees Fahrenheit. The Hubble Space Telescope has been used to make the most detailed global map yet of the thermal glow from this turbulent world. The astronomers were also able to map temperatures at different layers of the world's atmosphere and traced the amount and distribution of water vapor. The Jupiter-sized planet lies so close to its orange dwarf host star that it completes an orbit in just 19 hours. The planet is also gravitationally locked so that it keeps one hemisphere facing the star.
Hubble Telescope Detects 'Sunscreen' Layer on Distant Planet
Researchers using NASA's Hubble Space Telescope have detected a stratosphere and temperature inversion in the atmosphere of a planet several times the mass of Jupiter, called WASP-33b. Earth's stratosphere sits above the troposphere, the turbulent, active-weather region that reaches from the ground to the altitude where nearly all clouds top out. In the troposphere, the temperature is warmer at the bottom – ground level – and cools down at higher altitudes. The stratosphere is just the opposite: There, the temperature rises at higher altitudes. This is called a temperature inversion, and it happens because ozone in the stratosphere absorbs some of the sun's radiation, preventing it from reaching the surface and warming this layer of the atmosphere. Similar temperature inversions occur in the stratospheres of other planets in our solar system, such as Jupiter and Saturn. But WASP-33b is so close to its star that its atmosphere is a scathing 10,000 degrees Fahrenheit, and its atmosphere is so hot the planet might actually have titanium oxide rain.
Hubble Sees a 'Behemoth' Bleeding Atmosphere Around a Warm Neptune-Sized Exoplanet
Astronomers using NASA's Hubble Space Telescope have discovered an immense cloud of hydrogen dubbed "The Behemoth" bleeding off a planet orbiting a nearby star. The enormous, comet-like feature is about 50 times the size of the parent star. The hydrogen is evaporating from a warm, Neptune-sized planet, due to extreme radiation from the star. A phenomenon this large has never before been seen around any exoplanet. It may offer clues to how Super-Earths – massive, rocky, versions of Earth – are born around other stars through the evaporation of their outer layers of hydrogen. Finding "The Behemoth" could be a game-changer for characterizing atmospheres of the whole population of Neptune-sized planets and Super-Earths in ultraviolet observations.
Telescopes Team Up to Find Distant Uranus-Sized Planet Through Microlensing
The majority of planets discovered outside our solar system orbit close to their parent stars because these planets are the easiest to find. But to fully understand how distant planetary systems are put together, astronomers must conduct a census of all the planets around a star. So they need to look farther away from the star-from about the distance of Jupiter is from our sun, and beyond.
Now, astronomers using NASA's Hubble Space Telescope and the W. M. Keck Observatory in Hawaii have confirmed the existence of a Uranus-sized exoplanet orbiting far from its central star, discovered through a technique called gravitational microlensing. Microlensing occurs when a foreground star magnifies the light of a background star that momentarily aligns with it. The unique signature of the event, which is influenced by the relative motion of the stars across space, can reveal clues to the nature of the foreground star and any associated planets. Gravitational microlensing can find cold planets in long-period orbits that other methods cannot detect. This finding opens a new piece of discovery space in the extrasolar planet hunt: to uncover planets as far from their central stars as Jupiter and Saturn are from our sun.
A team of astronomers, including half a dozen from the Space Telescope Science Institute (STScI) in Baltimore, Maryland, have used the Gemini Observatory's new Gemini Planet Imager to find the most solar system-like planet ever directly imaged around another star. The planet, known as 51 Eridani b, is about two times the mass of Jupiter and orbits its host star at about 13 times the Earth-sun distance (equivalent to being between Saturn and Uranus in our solar system). The planet is located about 100 light-years away from Earth. The Gemini data provide scientists with the strongest-ever spectroscopic detection of methane in the atmosphere of an extrasolar planet, adding to its similarities to giant planets in our solar system. "This planet looks like a younger, slightly bigger version of Jupiter," said Dr. Laurent Pueyo of STScI, one of the astronomers who carefully measured the planet's light against the background glare of starlight. "That we can see so clearly the presence of methane for a planet a million times fainter than its star, even through the atmosphere, bodes very well for the future characterization of even fainter planets from space using the James Webb Space Telescope and the Wide-Field Infrared Survey Telescope."
Most Earth-Like Worlds Have Yet to Be Born, According to Theoretical Study
Astronomers are conducting extensive observations to estimate how many planets in our Milky Way galaxy might be potential abodes for life. These are collectively called "Earth-like" – in other words, Earth-sized worlds that are at the right distances from their stars for moderate temperatures to nurture the origin of life. The search for extraterrestrial intelligent life in the universe (SETI) is based on the hypothesis that some fraction of worlds, where life originates, go on to evolve intelligent technological civilizations. Until we ever find such evidence, Earth is the only known abode of life in the universe. But the universe is not only vastly big, it has a vast future. There is so much leftover gas from galaxy evolution available that the universe will keep cooking up stars and planets for a very long time to come. In fact, most of the potentially habitable Earth-like planets have yet to be born. This theoretical conclusion is based on an assessment of star-birth data collected by the Hubble Space Telescope and exoplanet surveys made by the planet-hunting Kepler space observatory.
Spirals in Dust Around Young Stars May Betray Presence of Massive Planets
A team of astronomers is proposing that huge spiral patterns seen around some newborn stars, merely a few million years old (about one percent our sun's age), may be evidence for the presence of giant, unseen planets. This idea not only opens the door to a new method of planet detection, but also could offer a look into the early formative years of planet birth. Though astronomers have cataloged thousands of planets orbiting other stars, the very earliest stages of planet formation are elusive because nascent planets are born and embedded inside vast, pancake-shaped disks of dust and gas encircling newborn stars. The conclusion that planets may betray their presence by modifying circumstellar disks on large scales is based on detailed computer modeling of how gas-and-dust disks evolve around newborn stars.
NASA Space Telescopes Solve Missing Water Mystery in Comprehensive Survey of Exoplanets
A survey of Jupiter-sized exoplanets conducted with the Hubble and Spitzer space telescopes has solved a long-standing mystery – why some of these worlds seem to have less water than expected. Astronomers have found that planets called hot Jupiters (which orbit very close to their stars) that are apparently cloud-free show strong signs of water. However, atmospheres of other planets with faint water signals also contained clouds and haze – both of which are known to hide water from view. The findings show that planetary atmospheres are much more diverse than expected. Also, the results offer insights into the wide range of planetary atmospheres in our galaxy and how planets are assembled.
Hubble Directly Measures Rotation of Cloudy 'Super-Jupiter'
Though nearly 2,000 planets have been found around other stars, the light from only a handful of them has ever been collected by the world's most powerful telescopes. Ironically, a lot of them are detected by the shadows they cast, as they pass in front of their parent stars. Follow-up observations measure the planet's feeble, but telltale, gravitational tug on its parent star. Now, Hubble Space Telescope astronomers have been able to pick up the faint infrared glow of a giant planet located 170 light-years away from Earth. Not only is it glowing, but also rhythmically flickering as the planet spins on its axis like a top. The interpretation is that the subtle changes in the planet's brightness are due to a variegated cloud cover of comparatively bright and dark patches coming and going. These measurements have led to an estimate of how fast the planet is spinning through direct observation – a first for exoplanet astronomers. The gaseous world completes one rotation approximately every 10 hours, which, coincidentally, is the same rotation rate as Jupiter.
The planet is dubbed a "super-Jupiter" because it is four times the mass of Jupiter, the largest known planet in our solar system. Because the planet is a comparative newborn, it is still hot as it contracts under gravity. These characteristics allow for infrared observations. The planet orbits a faint brown dwarf, designated 2M1207. The dwarf is too small to shine as stars do through nuclear fusion. The dwarf is so dim and far from the planet astronomers were able to isolate the planet's glow.
NASA's Hubble Telescope Makes First Atmospheric Study of Earth-Sized Exoplanets
The possibility of life on other worlds has fueled humankind's imagination for centuries. Over the past 20 years, the explosion of discoveries of planets orbiting other stars has sparked the search for worlds like Earth that could sustain life. Most of those candidates were found with other telescopes, including NASA's Kepler space observatory. NASA's Hubble Space Telescope has also made some unique contributions to the planet hunt. Astronomers used Hubble, for example, to make the first measurements of the atmospheric composition of extrasolar planets.
Now, astronomers have used Hubble to conduct the first search for atmospheres around temperate, Earth-sized planets beyond our solar system, uncovering clues that increase the chances of habitability on two exoplanets. They discovered that the exoplanets TRAPPIST-1b and TRAPPIST-1c, approximately 40 light-years away, are unlikely to have puffy, hydrogen-dominated atmospheres usually found on gaseous worlds. Those dense atmospheres act like a greenhouse, smothering any potential life. Observations from NASA's upcoming James Webb Space Telescope will help determine the full composition of these atmospheres and hunt for potential biosignatures, such as carbon dioxide and ozone, and methane.
Hubble Makes Precise Measure of Extrasolar World's True Mass
An international team of astronomers used the Hubble Space Telescope to help make a precise measurement of the mass of a planet outside our solar system. The Hubble results show that the planet is 1.89 to 2.4 times as massive as Jupiter, our solar system's largest orbiting body. Previous estimates, about which there are some uncertainties, place the planet's mass at a much wider range: between 1.9 and 100 times that of Jupiter's. The planet, called Gliese 876b, orbits the star Gliese 876. It is only the second planet outside our solar system for which astronomers have determined a precise mass.
Too Close for Comfort: Hubble Discovers an Evaporating Planet
Astronomers using NASA's Hubble Space Telescope have observed for the first time the atmosphere of a planet beyond our solar system evaporating into space. Most of the planet may eventually disappear, leaving only a dense core. The evaporating planet is a member of a type of planet called a "hot Jupiter," a giant gaseous planet that orbits very closely around its parent star, drawn to it like a moth to a flame. The scorched planet, called HD 209458b, orbits only 4 million miles (7 million kilometers) from its yellow, Sun-like star. The planet circles the parent star in a tight 3.5-day orbit. The Hubble observations reveal a hot and bloated hydrogen atmosphere, which is evaporating off the planet. This huge envelope of hydrogen resembles a comet with a tail trailing behind the planet.
NASA's Hubble Space Telescope precisely measured the mass of the oldest known planet in our Milky Way galaxy. At an estimated age of 13 billion years, the planet is more than twice as old as Earth's 4.5 billion years. It's about as old as a planet can be. It formed around a young, sun-like star barely 1 billion years after our universe's birth in the Big Bang. The ancient planet has had a remarkable history because it resides in an unlikely, rough neighborhood. It orbits a peculiar pair of burned-out stars in the crowded core of a cluster of more than 100,000 stars. The new Hubble findings close a decade of speculation and debate about the identity of this ancient world. Until Hubble's measurement, astronomers had debated the identity of this object. Was it a planet or a brown dwarf? Hubble's analysis shows that the object is 2.5 times the mass of Jupiter, confirming that it is a planet. Its very existence provides tantalizing evidence that the first planets formed rapidly, within a billion years of the Big Bang, leading astronomers to conclude that planets may be very abundant in our galaxy.
Oxygen and Carbon Found in Atmosphere of an Extrasolar Planet
NASA's Hubble Space Telescope has detected, for the first time ever, the presence of oxygen and carbon in the atmosphere of a planet outside our solar system.
Resembling a diamond-encrusted bracelet, a ring of brilliant blue star clusters wraps around the yellowish nucleus of what was once a normal spiral galaxy in this new image from NASA's Hubble Space Telescope (HST). This image is being released to commemorate the 14th anniversary of Hubble's launch on April 24, 1990 and its deployment from the space shuttle Discovery on April 25, 1990. The galaxy, cataloged as AM 0644-741, is a member of the class of so-called "ring galaxies." It lies 300 million light-years away in the direction of the southern constellation Volans.
Hubble Celebrates 15th Anniversary with Spectacular New Images
During the 15 years NASA's Hubble Space Telescope has orbited the Earth, it has taken more than 700,000 photos of the cosmos; images that have awed, astounded and even confounded astronomers and the public.
NASA released new views today of two of the most well-known objects Hubble has ever observed: the Whirlpool Galaxy (spiral galaxy M51)
and the Eagle Nebula
. These new images are among the largest and sharpest Hubble has ever taken. They were made with Hubble's newest camera, the Advanced Camera for Surveys (ACS). The images are so incredibly sharp, they could be enlarged to billboard size and still retain stunning details.
For the 15th anniversary, scientists used the ACS to record a new region of the eerie-looking Eagle Nebula. The Eagle Nebula image reveals a tall, dense tower of gas being sculpted by ultraviolet light from a group of massive, hot stars. The new Whirlpool Galaxy image showcases the spiral galaxy's classic features, from its curving arms, where newborn stars reside, to its yellowish central core that serves as home for older stars. A feature of considerable interest is the companion galaxy located at the end of one of the spiral arms.
Astronomers Find Smallest Extrasolar Planet Yet Around Normal Star
Using an armada of telescopes, an international team of astronomers has found the smallest planet ever detected around a normal star outside our solar system. The extrasolar planet is five times as massive as Earth and orbits a red dwarf, a relatively cool star, every 10 years. This artist's illustration shows an icy/rocky planet orbiting a dim star. The distance between the planet, designated OGLE-2005-BLG-390Lb, and its host is about three times greater than that between the Earth and the Sun. The planet's large orbit and its dim parent star make its likely surface temperature a frigid minus 364 degrees Fahrenheit (minus 220 degrees Celsius).
