BabuK
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- Jul 30, 2008
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Discovered using the Kepler Telescope, Kepler-186f isn’t exactly an Earth twin. The planet is very similar in size – within 10-percent of the Earth’s size – but it orbits its star, a red dwarf, once every 130 days and only gets a third of the sunlight that we get here on Earth. That means that noon on Kepler-186f is similar to an hour before sunset here. Nonetheless, it is close enough that it could potentially be the right conditions for life to flourish. Other planets in the habitable zone have either been too large or too far from a star to sustain liquid water.
Related: Earth Can Only Sustain Life for Another 1.75 Billion Years
Scientists don’t yet know what the planet is composed of, though research suggests it is likely rocky. The temperature of the planet depends on its atmosphere and we won’t know what that is made up of until scientists can do more research. Regardless, the discovery is incredibly important for science.”We know of just one planet where life exists — Earth. When we search for life outside our solar system, we focus on finding planets with characteristics that mimic that of Earth,” said Elisa Quintana, researcher at the SETI Institute. “Finding a habitable zone planet comparable to Earth in size is a major step forward.” In 2018, the James Webb Space Telescope launches to help us gather more info about this and other planets.
Although the Kepler space telescope has been hobbled by the failure of two of its four reaction wheels, which help stabilize the craft in space, two researchers propose modifying its mission so that the telescope could continue to produce useful data. Since its launch in 2009, Kepler has discovered 132 exoplanets and more than 3000 potential candidates.
7 NASA discoveries that will blow your mind
University of St. Andrews in the UK and Andrew Gould of theOhio State University propose that Kepler could alter its search using microlensing to search for worlds outside the regions of their stars that liquid water could exist known as the "snow line." The study of both extremes is necessary to help scientists better understand the so-called habitable zone where extraterrestrial life may one day be found. Although Earth-based telescopes can also use microlensing, Kepler, whose orbit trails Earth’s, can see things that can’t be seen from the ground.
Astronomers at the Harvard-Smithsonian CEnter for Astrophysiscs have announced after analyzing recent Kepler Mission data, that that the nearest planet in a habitable zone probably lies within fifteen light-years of Earth.
The Kepler mission has revolutionized the study of exoplanet statistics by increasing the number of known extrasolar planets and planet candidates by a factor of five, and by discovering systems with longer orbital periods and smaller planet radii than any of the prior exoplanet surveys. There is of course considerable interest in locating Earth-sized planets residing in the habitable zones of their stars, that is, having orbits producing surface temperatures that allow water to remain liquid - a prerequisite for the development of life.
Recent Kepler data showed that small stars, so-called M-dwarfs whose masses are about half a solar-mass and whose surface temperatures are less than about 4000K, are much more numerous than solar-type stars - about twelve times as common. Hunting for Earth-sized planets around M-dwarfs, therefore, is of particular interest.
Although the idea of finding habitable planets around M-dwarfs had been discussed as early as fifty years ago, the possibilities were considered slight because of two concerns about these smaller stars. The first is that because the star is cooler and less luminous than the Sun, the planet needs to be closer for its surface temperature to be suitable, but then gravity will tidally lock it facing the star (much as the Moon is tidally locked facing the Earth). With one face perpetually toward (and one away from) the star, the planet's surface might be either to hot or too cold. The second difficulty was that small stars tend to flare, perhaps affecting a planet's atmosphere.
New research, however, suggests that suitable habitable regions might develop on a planet in either of these cases. Since there are so many more small stars, and since it is so much easier to study their transiting planets because they are closer in and so have shorter orbital periods, a team of Kepler scientists began a focussed study of exoplanets around small stars.
CfA astronomers Courtney Dressing and David Charbonneau reported their conclusions in the Astrophysical Journal. Using Kepler, they identify 64 dwarf stars with 95 candidate (still awaiting confirmation) planets. This sample is large enough to reach some impressive statistical conclusions: on average every six small stars should host an Earth-sized planet in its habitable zone; and to 95% confidence, because small stars are so common, the nearest planet in a habitable zone probably lies within fifteen light-years of Earth.
The Daily Galaxy via Harvard-Smithsonian Center for Astrophysics and http://blogs.physicstoday.org/newspicks
