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Billions of habitable planets 'may exist within our galaxy' BILLIONS of potentially habitable planets may exist in our galaxy, the Milky Way, according to a new study. Around 100 'super-Earths' may be found on our galactic doorstep, at distances less than 30 light years from the sun. Astronomers came up with the prediction after conducting a survey of red dwarf stars, which account for 80pc of stars in the Milky Way. They calculate that around 40pc of red dwarfs have a rocky planet not much bigger than Earth orbiting the "habitable zone" where liquid surface water can exist. Where there is water, there could be life -- although being in the habitable zone is no guarantee that life has evolved on a planet. Astonishing Dr Xavier Bonfils, from Grenoble University in France, who led the international team, said: "Because red dwarfs are so common -- there are about 160 billion of them in the Milky Way -- this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone." The astronomers surveyed a carefully chosen sample of 102 red dwarfs using the European Southern Observatory's 3.6-metre telescope at La Silla, Chile. A total of nine super-Earths -- planets with masses between one and 10 times that of Earth -- were found. Two were within the habitable zones of the stars Gliese 581 and Gliese 667 C. The astronomers found that habitable zone super-Earths orbiting red dwarfs occurred with a frequency of around 41pc. On the other hand, massive planets similar to Jupiter and Saturn were rare around red dwarfs. Because red dwarfs are common near the sun, many "super-Earths" may not be far away in astronomical terms. The scientists estimate there could be around 100 habitable zone planets within 30 light years. Red dwarfs are cooler than the sun, which means that planets must orbit close to their parent stars to be warm enough to sustain life. This might not be good news for life. "The habitable zone around a red dwarf, where the temperature is suitable for liquid water to exist on the surface, is much closer to the star than the Earth is to the sun," said team member Dr Stephane Udry, from Geneva Observatory. The research is reported in the journal Astronomy & Astrophysics. Irish IndependentFollow @Independent_ie
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Novi rezultati istraživanja Europske svemirske promatračnice (ESO) pokazali su da su stjenoviti planeti ne mnogo veći od Zemlje u nastanjivim zonama crvenih zvijezda vrlo uobičajeni te da bi ih mnogo moglo biti čak i u našem neposrednom susjedstvu Međunarodni tim znanstvenika procjenjuje da samo u Mliječnoj stazi postoje deseci milijardi takvih planeta te stotinjak njih na manje od 30 svjetlosnih godina od Zemlje. Ova studija predstavlja prvo izravno mjerenje učestalosti super-Zemalja u orbitama crvenih patuljaka čiji je udio u ukupnom broju zvijezda u našoj galaksiji oko 80 posto. Rezultati se temelje na podacima koje je prikupio spektrograf HARPS Europske svemirske promatračnice (ESO) u Čileu: 'Naša nova promatranja uz pomoć HARPS-a pokazuju da oko 40 posto svih crvenih patuljaka ima super-Zemlje u nastanjivoj zoni u kojoj na površini planeta može postojati tekuća voda', rekao je voditelj tima Xavier Bonfils i pojasnio: 'Budući da su crveni patuljci toliko česti – u Mliječnoj stazi ih ima oko 160 milijardi – možemo zaključiti da samo u našoj galaksiji ima na desetke milijardi nastanjivih planeta.' HARPS-ov je tim tijekom šest godina detaljno proučio 102 crvena patuljka na južnom dijelu neba. U istraživanju je otkriveno ukupno devet super-Zemalja (planeta mase od jedan do 10 puta veće od Zemljine), među kojima i dva u nastanjivim zonama - Gliese 581 i Gliese 667 C. Na temelju rezultata astronomi su utvrdili da je učestalost super-Zemalja u nastanjivim zonama negdje oko 41 posto. Istraživanje je istovremeno pokazalo da su golemi planeti poput Jupitera i Saturna u orbitama crvenih patuljaka rijetki – ima ih manje od 12 posto. Budući da su crveni patuljci prilično česti u našem susjedstvu, procjenjuje se da bi na udaljenosti manjoj od 30 svjetlosnih godina moglo biti stotinjak super-Zemalja. 'Sada kada znamo da u orbitama obližnjih crvenih patuljaka ima mnogo super-Zemalja, uz pomoć HARPS-a i drugih instrumenata trebali bismo ih otkriti više. Neki od njih na svojim će orbitama proći ispred svojih zvijezda, što će otvoriti mogućnost da istražimo njihove atmosfere i potražimo znakove života', rekao je član tima Xavier Delfosse. - Sviđa vam se članak? Preporučite ga prijateljima putem ovih servisa: Pošaljite mailom