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Gain Staters, look up: In the faint flicker of a star above you, astronomers have discovered evidence of an alien world.
Researchers say the proposed new planet is unlike anything in our own solar system: larger than the Earth but smaller than Neptune, and far enough away from its dark red sun that any water on its surface is trapped in the ice .
But this frozen "super earth", the second closest exoplanet known to science, is a tantalizing clue to what might be available. And in a not-too-distant day, when telescopes will be able to photograph planets around other stars, it may well be the first new world we see.
"We are moving from science fiction to scientific reality," said Carnegie astronomer Johanna Teske, who contributed to a study of the new planet published last week in the journal Nature. "There are so many possibilities there."
The sun of the exoplanet, a tiny body called Barnard's star, is one of the closest neighbors to our solar system. The only stars closest are the Alpha Centauri triplets, mostly visible in the southern sky. One of these stars, Proxima Centauri, is orbiting a small planet, but the star's tendency to spit out deadly radiation bursts means that its planet will probably not be habitable.
Students from the Department of Physics and Astronomy at the University of New Hampshire are studying planets, just like this so-called super-Earth.
Exoplanets are of interest to college students as there is so much room for cutting-edge research on what exists on these planets and discovered over the past two decades, according to John Gianforte, director of the Observatory of the 39; UNH.
"We learn more every day," said Gianforte. "This is a very exciting new branch of astronomy."
Gianforte said that since the first scientific detection of an exoplanet in the mid-1990s, nearly 4,000 planets have been confirmed in more than 2,800 systems.
"Some of them have seven or eight planets," Gianforte said of the discovered systems. "The Holy Grail is to find planets similar to the Earth."
It means finding a planet with liquid water on it, which could support life as we know it, said Gianforte.
Barnard's star has long been "the great white whale" of the exoplanet hunt, said astronomer Carnegie, Paul Butler, co-author of the document Nature. It's only six light-years away from our sun and maybe twice as much. One of the leading architects of exoplanet research, astronomer Peter van de Kamp, proposed more than 50 years ago that this star could host a planet. In the 1970s, British astronomers studied the possibility of sending an unarmed spacecraft to probe the extraterrestrial system – although it was not proven that there was a planet to explore.
But it was only when the first discovery of exoplanets was confirmed in 1995 that the search for a world around Barnard's Star really began.
This red dwarf is one tenth of the mass of our sun and is too weak to be seen with the naked eye. But its low mass makes it ideal for analysis using the radial velocity exoplanet detection technique, which exploits the way a planet's gravitational pull makes a star wobble when it revolves around the -this.
A series of telescopes on three continents targeted Barnard's Star, allowing researchers to accumulate some 800 observations over a 20-year period. The authors of the study also drew on data collected by amateur astronomers.
It took the combined efforts of more than 50 researchers from nearly twenty institutions, but "slowly, a signal in our data came out of all this noise," said astronomer Ignasi Ribas, director of the Institute of Space Studies of Catalonia, Spain. and the main author of the Nature paper.
Yet the planet surrounding Barnard's star has not yet been determined. Astronomers are not sure whether it's rocks like Earth or gas and ice like Neptune. They know that its size must be at least three times larger than the Earth's, but it could be even bigger.
They are not even 100% sure that the planet is there, noted Ribas. The research has pushed the limits of the radial velocity detection technique, which becomes all the more difficult as a planet is far from its star. Mathematical models suggest that there is still a 0.8% probability that the apparent agitation of Barnard's star is caused by another factor, such as sunspots. For this reason, the exoplanet is considered a "candidate" rather than a confirmed discovery.
Nick Larose is from Derry and is senior at UNH. He is one of the college students doing research on exoplanets.
Aged 22, he plans to pursue a career in astronomy and said he relied on information gathered from space telescopes such as NASA's Kepler equipment to determine whether it was a planet orbiting a star.
"We watch the planet as it passes in front of the star and we witness the star's dimming as it passes in front of it," Larose said of a commonly used technique.
Larose said he is enthusiastic about the research and its results so far.
"I can really see that astronomical events are happening," said Larose.
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Sarah Kaplan, Washington Post reporter, and Kimberley Haas, Union Leader correspondent, contributed to this report.
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