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A research team discovered two Earth-like planets in our cosmic backyard, and they're located in the perfect zone for water to form on their presumably rocky surfaces. The planets orbit a sun known as "Teegarden's star," which is only A light-year is the distance that light travels in a year, or roughly 6 trillion miles or 10 trillion kilometers. The two planets look an awful lot like Earth and our neighboring worlds, the researchers said.

Galaxies, stars and planets

According to that project's observations, the newly found worlds orbit their parent star with periods of roughly five days and 11 days, respectively. That's very quick compared to planets orbiting our own sun even Mercury takes 88 days for a single circuit , but Teegarden's star is an M dwarf — a type of star that produces less light and energy than our own sun.

Any potentially habitable worlds would be found huddled closer to this star than Earth is to the sun, or their water would freeze. Thus, their orbits would be quicker. More planets could be lurking in Teegarden's star's solar system, the research team added, as many stars have more than a couple of planets orbiting them. The research team tried to find more evidence of planets using the "transit" method, which looks for subtle dips of brightness as a world passes in front of its star.

The scientists didn't detect any transits, but they did point out a coincidence of cosmic geometry: Any potential inhabitants on the newfound planets could use the transit method to see Earth. That's because from the vantage point of Teegarden's star, Earth orbits its sun at just the right angle to transit across the face of our star, allowing any astronomers "out there" to spot us as we pass by.

A paper based on the research was published in the journal Astronomy and Astrophysics.

Space Is Full Of Planets, And Most Of Them Don't Even Have Stars

A new study provides the most accurate estimate of the frequency that planets that are similar to Earth in size and in distance from their host star occur around stars similar to our Sun. Knowing the rate that these potentially habitable planets occur will be important for designing future astronomical missions to characterize nearby rocky planets around sun-like stars that could support life.


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A paper describing the model appears August 14, in The Astronomical Journal. Kepler, which was launched in and retired by NASA in when it exhausted its fuel supply, observed hundreds of thousands of stars and identified planets outside of our solar system -- exoplanets -- by documenting transit events. Transits events occur when a planet's orbit passes between its star and the telescope, blocking some of the star's light so that it appears to dim.

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By measuring the amount of dimming and the duration between transits and using information about the star's properties astronomers characterize the size of the planet and the distance between the planet and its host star. Ford, professor of astronomy and astrophysics at Penn State and one of the leaders of the research team.

Planet Earth compared to other planets and stars in size.

However, simply counting exoplanets of a given size or orbital distance is misleading, since it's much harder to find small planets far from their star than to find large planets close to their star. To overcome that hurdle, the researchers designed a new method to infer the occurrence rate of planets across a wide range of sizes and orbital distances. Our novel approach allowed the team to account for several effects that have not been included in previous studies. The results of this study are particularly relevant for planning future space missions to characterize potentially Earth-like planets.

Space Is Full Of Planets, And Most Of Them Don't Even Have Stars

While the Kepler mission discovered thousands of small planets, most are so far away that it is difficult for astronomers to learn details about their composition and atmospheres. Searching for evidence of life on Earth-size planets in the habitable zone of sun-like stars will require a large new space mission.

How large that mission needs to be will depend on the abundance of Earth-size planets. NASA and the National Academies of Science are currently exploring mission concepts that differ substantially in size and their capabilities.

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If Earth-size planets are rare, then the nearest Earth-like planets are farther away and a large, ambitious mission will be required to search for evidence of life on potentially Earth-like planets. On the other hand, if Earth-size planets are common, then there will be Earth-size exoplanets orbiting stars that are close to the sun and a relatively small observatory may be able to study their atmospheres. Based on their simulations, the researchers estimate that planets very close to Earth in size, from three-quarters to one-and-a-half times the size of earth, with orbital periods ranging from to days, occur around approximately one in four stars.

Importantly, their model quantifies the uncertainty in that estimate. They recommend that future planet-finding missions plan for a true rate that ranges from as low about one planet for every 33 stars to as high as nearly one planet for every two stars. The Center for Exoplanets and Habitable Worlds at Penn State includes faculty and students who are involved in the full spectrum of extrasolar planet research.

opinisdevni.cf A Penn State team built the Habitable Zone Planet Finder, an instrument to search for low-mass planets around cool stars, which recently began science operations at the Hobby-Eberly Telescope, of which Penn State is a founding partner.