Scientists from University of California, Berkeley, and University of Hawaii, Manoa, have statistically determined that twenty percent of Sun-like stars in our galaxy have Earth-sized planets that could host life. The findings, gleaned from data collected from NASA’s Kepler spacecraft and the W. M. Keck Observatory, now satisfy Kepler’s primary mission: to determine how many of the 100 billion stars in our galaxy have potentially habitable planets. The results are being published November 4 in the journal Proceedings of the National Academy of Sciences.
Artist’s rendering of the planetary system HR 8799 at an early stage in its evolution. Credit: Dunlap Institute for Astronomy & Astrophysics“What this means is, when you look up at the thousands of stars in the night sky, the nearest sun-like star with an Earth-size planet in its habitable zone is probably only 12 light years away and can be seen with the naked eye. That is amazing,” said UC Berkeley graduate student Erik Petigura, who led the analysis of the Kepler and Keck Observatory data.
“For NASA, this number – that every fifth star has a planet somewhat like Earth – is really important, because successor missions to Kepler will try to take an actual picture of a planet, and the size of the telescope they have to build depends on how close the nearest Earth-size planets are,” said Andrew Howard, astronomer with the Institute for Astronomy at the University of Hawaii. “An abundance of planets orbiting nearby stars simplifies such follow-up missions.”
A team of astronomers has found the first Earth-sized planet outside the solar system that has a rocky composition like that of Earth. This exoplanet, known as Kepler-78b, orbits its star very closely every 8.5 hours, making it much too hot to support life. The results are being published in the journal Nature.
Artist impression of the planet Kepler-78b and its host star. Credit: Karen Teramura (UH/IfA)This Earth-sized planet was discovered using data from NASA’s Kepler Space Telescope, and confirmed and characterized with the W. M. Keck Observatory.
Every 8.5 hours the planet passes in front of its host star, blocking a small fraction of the starlight. These telltale dimmings were picked up by researchers analyzing the Kepler data.
The team led by Dr. Andrew Howard (Institute for Astronomy, University of Hawaii at Manoa) then measured the mass of the planet with the Keck Observatory on Mauna Kea, in Hawaii. Using the ten-meter Keck I telescope fitted with the HIRES instrument, the team employed the radial velocity method to measure how much an orbiting planet causes its star to wobble, to determine the planet’s mass. This is another excellent example of the synergy between the Kepler survey, which has identified more than 3,000 potential exoplanet candidates, and Keck Observatory, which plays a leading role in conducting precise Doppler measurements of the exoplanet candidates.
Astronomers have found the shattered remains of an asteroid that contained huge amounts of water orbiting an exhausted star, or white dwarf. This suggests that the star GD 61 and its planetary system – located about 150 light years away and at the end of its life – had the potential to contain Earth-like exoplanets.
The new research findings used data collected from NASA’s Hubble Space Telescope, both of W. M. Keck Observatory’s Keck I and Keck II telescopes, as well NASA’s FUSE telescope, and are reported today in the journal Science.
Artist impression of a rocky and water-rich asteroid being torn apart by the strong gravity of the white dwarf star GD 61. Credit: Copyright Mark A. Garlick, space-art.co.uk, University of Warwick and University of Cambridge.This is the first time both water and a rocky surface – two key ingredients for habitable planets – have been found together beyond our solar system.
Earth is essentially a “dry” planet, with only 0.02% of its mass as surface water, meaning oceans came long after it had formed; most likely when water-rich asteroids in the solar system crashed into our planet.
The asteroid analyzed is composed of 26% water mass, very similar to Ceres, the largest asteroid in the main belt of our solar system. Both are vastly more water-rich compared with Earth.
The new discovery shows the same water delivery system could have occurred in this distant, dying star’s solar system – as latest evidence points to it containing a similar type of water-rich asteroid that would have first brought water to Earth.
Astronomers at the Universities of Cambridge and Warwick say this is the first “reliable evidence” for water-rich, rocky planetary material in any extrasolar planetary system.
A team of scientists recently confirmed six, and possibly seven, planets orbiting a star system a mere 22 light-years from Earth. More importantly, three of those planets are super-Earths, lying in the Goldilocks Zone where liquid water could exist, making them possible candidates for the presence of life. This is the first system found with a fully-packed habitable zone. The findings will be published in the journal Astronomy & Astrophysics on June 26.
Previous studies of the triple star system called Gliese 667C showed the star hosts three planets with one of them in the habitable zone. Now, a team of astronomers has reexamined the system by re-mining existing European Southern Observatory’s HARPS data and combining it with data collected from the W. M. Keck Observatory and the Magellan Telescope to find evidence for up to seven planets around the star. These planets orbit the third faintest star of a triple star system. The two other suns would look like a pair of very bright stars visible in the daytime and at night they would provide as much illumination as the full Moon. Continue reading “Scientists Discover System with Three Planets in Habitable Zone”
Bad news today, the Kepler Spacecraft has suffered a mechanical failure. As feared, one more of the reaction wheels that keep the spacecraft stabilized has failed. Of the set of four reaction wheels two have now failed, at least three are required to continue the mission.
Artist’s rendition of the Kepler Spacecraft in orbit around the Sun peering at a distant solar system, press release image from the NASA Kepler websiteKeck and Kepler have been a potent team in finding and confirming hundreds of exoplanets. Kepler detects alien world through the transit technique, the very slight dimming of a star as a planet passes in front. Data from an instrument such as Keck’s HIRES spectrograph is required to confirm the find through the use of radial velocity data. Using the technique Kepler has discovered 130 extrasolar planets that are now confirmed. An amazing 2,700 possible planets are awaiting confirmation. Besides the discovery of exoplanets the Kepler data set has been a bonanza to astronomers looking for other phenomena. Magnitude data on more than 100,000 stars with unprecedented precision has allowed the discovery and study of a widerange of stellarphenomena.
Engineers will continue to see if the reaction wheel can be nursed back to some level of function in an effort to salvage the mission. The prognosis is not good, it is likely the Kepler mission has ended. In any case it will take astronomers years to learn what the massive haul of Kepler data can teach us and to work through the backlog of candidate planets. In a few years the spectacular success of Kepler will be followed up by TESS, the Transiting Exoplanet Survey Satellite, due for launch in 2017.
Three exoplanets orbiting a young star 140 light years away are captured using Keck Observatory’s near-infrared adaptive optics. Image credit Christian Marois, NRC and Bruce Macintosh, LLNL
Gone are the days of being able to count the number of known planets on your fingers. Today, there are more than 800 confirmed exoplanets — planets that orbit stars beyond our sun — and more than 2,700 other candidates. What are these exotic planets made of? Unfortunately, you cannot stack them in a jar like marbles and take a closer look. Instead, researchers are coming up with advanced techniques for probing the planets’ makeup.
One breakthrough to come in recent years is direct imaging of exoplanets. Ground-based telescopes have begun taking infrared pictures of the planets posing near their stars in family portraits. But to astronomers, a picture is worth even more than a thousand words if its light can be broken apart into a rainbow of different wavelengths.
Those wishes are coming true as researchers are beginning to install infrared cameras on ground-based telescopes equipped with spectrographs. Spectrographs are instruments that spread an object’s light apart, revealing signatures of molecules. Project 1640, partly funded by NASA’s Jet Propulsion Laboratory, Pasadena, Calif., recently accomplished this goal using the Palomar Observatory near San Diego.
A nice short video on Keck and the hunt to find and confirm extrasolar planets. It features regular Keck observer Nader Haghighipour from the Institute for Astronomy, University of Hawaii talking about his research into exoplanets.
I had a chance to help out with some of the interior shots. We had to hurry as the film crew was running late and they were up against the schedule, it was time to release the telescopes to the astronomers for the night. It is nice to see the crew got the needed shots and to see the final result a few months later.
A team of international scientists using the W. M. Keck Observatory has made the most detailed examination yet of the atmosphere of a Jupiter-size planet beyond our Solar System.
According to lead author Quinn Konopacky, an astronomer with the Dunlap Institute for Astronomy & Astrophysics, University of Toronto and a former Lawrence Livermore National Laboratory (LLNL) postdoc, “We have been able to observe this planet in unprecedented detail because of Keck Observatory’s advanced instrumentation, our ground-breaking observing and data processing techniques, and because of the nature of the planetary system.” The paper appears online March 14th in Science Express, and March 22nd in the journal Science.
“This is the sharpest spectrum ever obtained of an extrasolar planet,” said co-author Bruce Macintosh, an astronomer at LLNL. “This shows the power of directly imaging a planetary system—the exquisite resolution afforded by these new observations has allowed us to really begin to probe planet formation.”
Artist’s rendering of the planetary system HR 8799 at an early stage in its evolution. Credit: Dunlap Institute for Astronomy & Astrophysics
The team, using the OSIRIS instrument fitted on the mighty Keck II telescope on the summit of Mauna Kea, Hawaii, has uncovered the chemical fingerprints of specific molecules, revealing a cloudy atmosphere containing water vapor and carbon monoxide. “With this level of detail,” says coauthor Travis Barman, an astronomer at the Lowell Observatory, “we can compare the amount of carbon to the amount of oxygen present in the atmosphere, and this chemical mix provides clues as to how the planetary system formed.”
There has been uncertainty about how planets in other solar systems formed, with two leading models, called core accretion and gravitational instability. When stars form, they are surrounded by a planet-forming disk. In the first scenario, planets form gradually as solid cores slowly grow big enough to start absorbing gas from the disk. In the latter, planets form almost instantly as parts of the disk collapse on themselves. Planetary properties, like the composition of a planet’s atmosphere, are clues as to whether a system formed according to one model or the other.
A team of astronomers from the University of California, Berkeley and the University of Hawaii at Manoa has found that 17 percent of all sun-like stars have planets one to two times the diameter of Earth in close orbits. The finding, based on an analysis of the first three years of data from NASA’s Kepler mission and the W. W. Keck Observatory on the summit of Mauna Kea, Hawaii, was announced at the American Astronomical Society meeting in Long Beach, California this week.
While other studies had shown that planets around stars are common in our galaxy, until this study, it remained unclear if this is true for Earth-size planets.
The fraction of sun-like stars having planets of different sizes, orbiting within one-fourth of the Earth-sun distance (0.25 AU) of the host star. Image credit: Erik Petigura, Geoff Marcy, Andrew Howard,The team consists of UC Berkeley graduate student Erik Petigura, former UC Berkeley postdoctoral fellow Andrew Howard, now on the faculty of the UH Manoa Institute for Astronomy, and UC Berkeley professor Geoff Marcy.
To find planets, the Kepler space telescope repeatedly images 150,000 stars in a small region of the sky. It looks for a tiny dip in each star’s brightness that indicates a planet is passing in front of it, much like Venus passed between Earth and the sun last summer.
We took a census of the planets detected by the Kepler Space Telescope,” said Howard. “Erik Petigura wrote a new pipeline to detect the shallow dimmings of Earth-size planets in Kepler photometry. With his efficient and well-calibrated pipeline we could confidently report the size distribution of close-in planets down to Earth-size. The result is that Earth-size planets are just a common as planets twice Earth size. Remarkable.”
Kepler’s follow-up observers confirm new discoveries
More than 2,300 exoplanet candidate discoveries have made it the most prolific planet hunter in history. But even NASA’s Kepler mission needs a little help from its friends.
An artist’s illustration of an exoplanet system. Credit: Haven Giguere/YaleEnter the Kepler follow-up observation program, a consortium of astronomers dedicated to getting in-depth with the mission’s findings and verifying them to an extremely high degree of confidence.
A single Kepler observation alone is often not enough to prove that the telescope has found an exoplanet, said Nick Gautier, the mission’s deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who coordinated and continues to help run Kepler’s robust follow-up program.
Kepler finds exoplanets by watching for worlds that move directly between the telescope and their host stars. As they do this, they block a tiny fraction of the star’s light, an event astronomers call a “transit.”
