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Orbiting in the Habitable Zone of Two Suns
This diagram
compares our own solar system to Kepler-47, a double-star system
containing two planets, one orbiting in the so-called "habitable zone."
This is the sweet spot in a planetary system where liquid water might
exist on the surface of a planet.
Unlike our own solar system, Kepler-47 is home to two stars. One star is
similar to the sun in size, but only 84 percent as bright. The second
star is diminutive, measuring only one-third the size of the sun and
less than one percent as bright. As the stars are smaller than our sun,
the systems habitable zone is closer in.
The habitable zone of the system is ring-shaped, centered on the larger
star. As the primary star orbits the center of mass of the two stars
every 7.5 days, the ring of the habitable zone moves around.
This artist's rendering shows the planet comfortably orbiting within the habitable zone, similar to where Earth circles the sun. One year, or orbit, on Kepler-47c is 303 days. While not a world hospitable for life, Kepler-47c is thought to be a gaseous giant, slightly larger than Neptune, where an atmosphere of thick bright water-vapor clouds might exist.
The discovery demonstrates the diversity of planetary systems in our galaxy and provides more opportunities to search for life as we know it.
For more, visit: http://www.nasa.gov/mission_pages/kepler/news/kepler-47.html
Credit: NASA/JPL-Caltech/T. Pyle
This artist's rendering shows the planet comfortably orbiting within the habitable zone, similar to where Earth circles the sun. One year, or orbit, on Kepler-47c is 303 days. While not a world hospitable for life, Kepler-47c is thought to be a gaseous giant, slightly larger than Neptune, where an atmosphere of thick bright water-vapor clouds might exist.
The discovery demonstrates the diversity of planetary systems in our galaxy and provides more opportunities to search for life as we know it.
For more, visit: http://www.nasa.gov/mission_pages/kepler/news/kepler-47.html
Credit: NASA/JPL-Caltech/T. Pyle
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Size of Kepler Planet Candidates
Since the last Kepler
catalog was released in February 2012, the number of candidates
discovered in the Kepler data has increased by 20 percent and now totals
2,740 potential planets orbiting 2,036 stars. Based on observations
conducted May 2009 to March 2011, the most dramatic increases are seen
in the number of Earth-size and super Earth-size candidates discovered,
which grew by 43 and 21 percent respectively.
Scientists analyzed more than 13,000 transit-like signals called
'threshold crossing events' to eliminate known spacecraft
instrumentation and astrophysical false positives, phenomena that
masquerade as planetary candidates, to identify the potential new
planets.
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› Full SizeRed Dwarf Planet
The artist's conception shows a hypothetical planet with two moons orbiting in the habitable zone of a red dwarf star. Using publicly available data from NASA’s Kepler space telescope, astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) estimate that six percent of red dwarf stars have an Earth-sized planet in the "habitable zone," the range of distances from a star where the surface temperature of an orbiting planet might be suitable for liquid water.The majority of the sun's closest stellar neighbors are red dwarfs. Researchers now believe that an Earth-size planet with a moderate temperature may be just 13 light-years away.
Astronomers don't know if life could exist on a planet orbiting a red dwarf. However, this finding suggests that the most common type of the star in the galaxy may provide many more cosmic neighborhoods to search for planets that may be like our own.
Image credit: D. Aguilar/Harvard-Smithsonian Center for Astrophysics
Using publicly available data from NASA’s Kepler space telescope,
astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA)
estimate that six percent of red dwarf stars in the galaxy have
Earth-size planets in the "habitable zone," the range of distances from a
star where the surface temperature of an orbiting planet might be
suitable for liquid water.
The majority of the sun's closest stellar neighbors are red dwarfs. Researchers now believe that an Earth-size planet with a moderate temperature may be just 13 light-years away.
"We don't know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined," said Natalie Batalha, Kepler mission scientist, NASA's Ames Research Center in Moffett Field, Calif.
The research team analyzed 95 planet candidates in the Kepler catalog orbiting 64 red dwarf stars. Most of these candidates aren't the right size or temperature to be considered Earth-like, as defined by the size relative to Earth and the distance from the host star. However, three candidates are both temperate and smaller than twice the size of Earth.
Red dwarf stars are smaller, cooler, and fainter than the sun. An average red dwarf is only one-third as large and one-thousandth as bright as the sun. Consequently, the not too hot or not too cold habitable zone would be much closer to a cooler star than it is to the sun.
"This close-in habitable zone around cooler stars makes planets more vulnerable to the effects of stellar flares and gravitational interactions, complicating our understanding of their likely habitability,” said Victoria Meadows, professor at the University of Washington and principal investigator with the NASA Astrobiology Institute. "But, if the planets predicted by this study are indeed found very nearby, then it will make it easier for us to make the challenging observations needed to learn more about them, including whether or not they can or do support life."
The three planetary candidates highlighted in this study are Kepler Object of Interest (KOI) 1422.02, which is 90 percent the size of Earth in a 20-day orbit; KOI-2626.01, 1.4 times the size of Earth in a 38-day orbit; and KOI-854.01, 1.7 times the size of Earth in a 56-day orbit.
Located between 300 to 600 light-years away, the three candidates orbit stars with temperatures ranging from 3,400 to 3,500 degrees Kelvin. By comparison, the temperature of the sun is nearly 5,800 degrees Kelvin.
Kepler is the first NASA mission capable of finding Earth-size planets in or near the habitable zone. Kepler is detecting planets and possible candidates with a wide range of sizes and orbital distances to help scientists better understand our place in the galaxy.
Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace and Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with JPL at 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 the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters.
For more information about the discovery, see the CfA press release or watch the press conference.
For information about the Kepler Mission, click here.
The majority of the sun's closest stellar neighbors are red dwarfs. Researchers now believe that an Earth-size planet with a moderate temperature may be just 13 light-years away.
"We don't know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined," said Natalie Batalha, Kepler mission scientist, NASA's Ames Research Center in Moffett Field, Calif.
The research team analyzed 95 planet candidates in the Kepler catalog orbiting 64 red dwarf stars. Most of these candidates aren't the right size or temperature to be considered Earth-like, as defined by the size relative to Earth and the distance from the host star. However, three candidates are both temperate and smaller than twice the size of Earth.
Red dwarf stars are smaller, cooler, and fainter than the sun. An average red dwarf is only one-third as large and one-thousandth as bright as the sun. Consequently, the not too hot or not too cold habitable zone would be much closer to a cooler star than it is to the sun.
"This close-in habitable zone around cooler stars makes planets more vulnerable to the effects of stellar flares and gravitational interactions, complicating our understanding of their likely habitability,” said Victoria Meadows, professor at the University of Washington and principal investigator with the NASA Astrobiology Institute. "But, if the planets predicted by this study are indeed found very nearby, then it will make it easier for us to make the challenging observations needed to learn more about them, including whether or not they can or do support life."
The three planetary candidates highlighted in this study are Kepler Object of Interest (KOI) 1422.02, which is 90 percent the size of Earth in a 20-day orbit; KOI-2626.01, 1.4 times the size of Earth in a 38-day orbit; and KOI-854.01, 1.7 times the size of Earth in a 56-day orbit.
Located between 300 to 600 light-years away, the three candidates orbit stars with temperatures ranging from 3,400 to 3,500 degrees Kelvin. By comparison, the temperature of the sun is nearly 5,800 degrees Kelvin.
Kepler is the first NASA mission capable of finding Earth-size planets in or near the habitable zone. Kepler is detecting planets and possible candidates with a wide range of sizes and orbital distances to help scientists better understand our place in the galaxy.
Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace and Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with JPL at 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 the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters.
For more information about the discovery, see the CfA press release or watch the press conference.
For information about the Kepler Mission, click here.
Ames Research Center, Moffett Field, Calif.
650-604-6982
michele.johnson@nasa.gov
http://kepler.nasa.gov/news/nasakeplernews/index.cfm?FuseAction=ShowNews&NewsID=214
Kepler Discoveries
Planet Candidates ---|--- Eclipsing Binaries ---|--- Papers ---|--- Data Archives ---|--- Light Curves
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(Click on planet Name to get more information about the planet. Click on KOI number to find discovery article.)NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
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