1000TH EXOPLANET DISCOVERED AND MORE HABITABLE PLANETS FOUND

FROM:  NASA 
NASA’s Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones

NASA Kepler's Hall of Fame: Of the more than 1,000 verified planets found by NASA's Kepler Space Telescope, eight are less than twice Earth-size and in their stars' habitable zone. All eight orbit stars cooler and smaller than our sun. The search continues for Earth-size habitable zone worlds around sun-like stars.
How many stars like our sun host planets like our Earth? NASA’s Kepler Space Telescope continuously monitored more than 150,000 stars beyond our solar system, and to date has offered scientists an assortment of more than 4,000 candidate planets for further study -- the 1,000th of which was recently verified.
Using Kepler data, scientists reached this millenary milestone after validating that eight more candidates spotted by the planet-hunting telescope are, in fact, planets. The Kepler team also has added another 554 candidates to the roll of potential planets, six of which are near-Earth-size and orbit in the habitable zone of stars similar to our sun.

Three of the newly-validated planets are located in their distant suns’ habitable zone, the range of distances from the host star where liquid water might exist on the surface of an orbiting planet. Of the three, two are likely made of rock, like Earth.

"Each result from the planet-hunting Kepler mission's treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe," said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “The Kepler team and its science community continue to produce impressive results with the data from this venerable explorer."

To determine whether a planet is made of rock, water or gas, scientists must know its size and mass. When its mass can’t be directly determined, scientists can infer what the planet is made of based on its size.

Two of the newly validated planets, Kepler-438b and Kepler-442b, are less than 1.5 times the diameter of Earth. Kepler-438b, 475 light-years away, is 12 percent bigger than Earth and orbits its star once every 35.2 days. Kepler-442b, 1,100 light-years away, is 33 percent bigger than Earth and orbits its star once every 112 days.

Both Kepler-438b and Kepler-442b orbit stars smaller and cooler than our sun, making the habitable zone closer to their parent star, in the direction of the constellation Lyra. The research paper reporting this finding has been accepted for publication in The Astrophysical Journal.

"With each new discovery of these small, possibly rocky worlds, our confidence strengthens in the determination of the true frequency of planets like Earth," said co-author Doug Caldwell, SETI Institute Kepler scientist at NASA's Ames Research Center at Moffett Field, California. "The day is on the horizon when we’ll know how common temperate, rocky planets like Earth are.”

With the detection of 554 more planet candidates from Kepler observations conducted May 2009 to April 2013, the Kepler team has raised the candidate count to 4,175. Eight of these new candidates are between one to two times the size of Earth, and orbit in their sun's habitable zone. Of these eight, six orbit stars that are similar to our sun in size and temperature. All candidates require follow-up observations and analysis to verify they are actual planets.

“Kepler collected data for four years -- long enough that we can now tease out the Earth-size candidates in one Earth-year orbits”, said Fergal Mullally, SETI Institute Kepler scientist at Ames who led the analysis of a new candidate catalog. “We’re closer than we’ve ever been to finding Earth twins around other sun-like stars. These are the planets we’re looking for”.

These findings also have been submitted for publication in The Astrophysical Journal Supplement.

Work is underway to translate these recent discoveries into estimates of how often rocky planets appear in the habitable zones of stars like our sun, a key step toward NASA's goal of understanding our place in the universe.

Scientists also are working on the next catalog release of Kepler’s four-year data set. The analysis will include the final month of data collected by the mission and also will be conducted using sophisticated software that is more sensitive to the tiny telltale signatures of small Earth-size planets than software used in the past.
Ames is responsible for Kepler's mission operations, ground system development and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colorado, developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate in Washington.

THE DEAD EXOPLANET

FROM: NASA
Study of Hubble Data Revives 'Dead' Exoplanet

In 2008, Hubble astronomers announced the detection of a giant planet around the bright star Fomalhaut. Recent studies have questioned this conclusion. Now, a reanalysis of Hubble data has revived the "deceased" exoplanet as a dust-shrouded world with less than twice the mass of Jupiter.

Credit: NASA's Goddard Space Flight Center

NASA OBSERVES ERUPTION OF SUN AND EVAPORATION OF PLANETS ATMOSPHERE

 FROM:  NASA
This artist's rendering illustrates the evaporation of HD 189733b's atmosphere in response to a powerful eruption from its host star. NASA's Hubble Space Telescope detected the escaping gases and NASA's Swift satellite caught the stellar flare. (Credit: NASA's Goddard Space Flight Center) 


HUBBLE, SWIFT DETECT FIRST-EVER CHANGES IN AN EXOPLANET ATMOSPHERE
WASHINGTON -- An international team of astronomers using data from NASA's Hubble Space Telescope has made an unparalleled observation, detecting significant changes in the atmosphere of a planet located 
beyond our solar system. 

The scientists conclude the atmospheric variations occurred in response to a powerful eruption on the planet's host star, an event observed by NASA's Swift satellite. "The multiwavelength coverage by Hubble and Swift has given us an unprecedented view of the interaction between a flare on an active star and the atmosphere of a giant planet," said lead researcher Alain Lecavelier des Etangs at the Paris Institute of Astrophysics (IAP), part of the French National Scientific Research Center located at Pierre and Marie Curie University in Paris. 

The exoplanet is HD 189733b, a gas giant similar to Jupiter, but about 14 percent larger and more massive. The planet circles its star at a distance of only 3 million miles, or about 30 times closer than Earth's distance from the sun, and completes an orbit every 2.2 days. Its star, named HD 189733A, is about 80 percent the size and mass of our sun. 

Astronomers classify the planet as a "hot Jupiter." Previous Hubble observations show that the planet's deep atmosphere reaches a temperature of about 1,900 degrees Fahrenheit (1,030 C). HD 189733b periodically passes across, or transits, its parent star, and these events give astronomers an opportunity to probe its atmosphere and environment. In a previous study, a group led by Lecavelier des Etangs used Hubble to show that hydrogen gas was 

escaping from the planet's upper atmosphere. The finding made HD 189733b only the second-known "evaporating" exoplanet at the time.  The system is just 63 light-years away, so close that its star can be seen with binoculars near the famous Dumbbell Nebula. This makes HD 

189733b an ideal target for studying the processes that drive atmospheric escape. 

"Astronomers have been debating the details of atmospheric evaporation for years, and studying HD 189733b is our best opportunity for understanding the process," said Vincent Bourrier, a doctoral student at IAP and a team member on the new study. 

When HD 189733b transits its star, some of the star's light passes through the planet's atmosphere. This interaction imprints information on the composition and motion of the planet's atmosphere into the star's light. 

In April 2010, the researchers observed a single transit using Hubble's Space Telescope Imaging Spectrograph (STIS), but they detected no trace of the planet's atmosphere. Follow-up STIS observations in September 2011 showed a surprising reversal, with 

striking evidence that a plume of gas was streaming away from the 

exoplanet. 

The researchers determined that at least 1,000 tons of gas was leaving the planet's atmosphere every second. The hydrogen atoms were racing away at speeds greater than 300,000 mph. The findings will appear in an upcoming issue of the journal Astronomy & Astrophysics. Because X-rays and extreme ultraviolet starlight heat the planet's 

atmosphere and likely drive its escape, the team also monitored the star with Swift's X-ray Telescope (XRT). On Sept. 7, 2011, just eight hours before Hubble was scheduled to observe the transit, Swift was monitoring the star when it unleashed a powerful flare. It brightened 

by 3.6 times in X-rays, a spike occurring atop emission levels that already were greater than the sun's. 

"The planet's close proximity to the star means it was struck by a blast of X-rays tens of thousands of times stronger than the Earth suffers even during an X-class solar flare, the strongest category," said co-author Peter Wheatley, a physicist at the University of 

Warwick in England. 

After accounting for the planet's enormous size, the team notes that HD 189733b encountered about 3 million times as many X-rays as Earth receives from a solar flare at the threshold of the X class. Hubble is a project of international cooperation between NASA and the European Space Agency. Swift is operated in collaboration with several U.S. institutions and partners in the United Kingdom, Italy, Germany and Japan. NASA's Goddard Space Flight Center in Greenbelt, Md., manages both missions. 

THE THREE LITTLE EXOPLANETS AND THE RED DWARF STAR

FROM:  NASA
Image Credit: NASA/JPL-Caltech
Compact Planetary System
This artist's concept depicts a planetary system so compact that it's more like Jupiter and its moons than a star and its planets. Astronomers using data from NASA's Kepler mission and ground-based telescopes recently confirmed that the system, called KOI-961, hosts the three smallest exoplanets currently known to orbit a star other than our sun. An exoplanet is a planet that resides outside of our solar system.

The star, which is located about 130 light-years away in the Cygnus constellation, is a red dwarf that is one-sixth the size of the sun, or just 70 percent bigger than Jupiter. The star is also cooler than our sun, and gives off more red light than yellow.

The smallest of the three planets, called KOI-961.03, is actually located the farthest from the star, and is pictured in the foreground. This planet is about the size of Mars, with a radius of 0.57 times that of Earth. The next planet to the upper right is KOI-961.01, which is 0.78 times the radius of Earth. The planet closest to the star is KOI-961.02, with a radius 0.73 times the Earth's.

All three planets whip around the star in less than two days, with the closest planet taking less than half a day. Their close proximity to the star also means they are scorching hot, with temperatures ranging from 350 to 836 degrees Fahrenheit (176 to 447 degrees Celsius). The star's habitable zone, or the region where liquid water could exist, is located far beyond the planets.

The ground-based observations contributing to these discoveries were made with the Palomar Observatory, near San Diego, Calif., and the W.M. Keck Observatory atop Mauna Kea in Hawaii.