Entries in Stars (2)


Scientists Say 1 in 6 Stars May Have Own Earth-Size Planet

M. Kornmesser /ESA/NASA(NEW YORK) -- The Kepler Space Telescope, an observatory launched by NASA in 2009 to find Earth-like planets, has provided data that suggests there are billions of them -- enough that one in six stars may have at least one orbiting it.

Out of roughly 100 billion stars in the Milky Way galaxy, a new analysis of Kepler data shows that around 17 percent of them have Earth-sized planets orbiting them, meaning there could be as many as 17 billion Earth-sized worlds.

Such planets, trillions of miles or more away, are too small for current technology to see, so Kepler watches thousands of stars -- and if one dims by a tiny amount regularly, that's a sign that perhaps a planet has crossed its face, blocking a little of its light. Researchers at the Harvard-Smithsonian Center for Astrophysics analyzed the entire data set from Kepler and concluded that virtually all sun-like stars have at least one planet.

"This is the first time we've been able to say with any certainty how many stars out there have Earth-like planets," Christine Pulliam of with the Harvard-Smithsonian Center for Astrophysics told ABC News.

Francois Fression of the Harvard-Smithsonian Center presented the statistical study Monday at a meeting of the American Astronomical Society in Long Beach, Calif. A paper detailing the research has been accepted for publication in The Astrophysical Journal.

Contradicting previous findings, researchers also found that the type of star does not make certain sizes of planets more or less common. The team grouped planets into five different sizes and 17 percent of them, roughly 1 in 6, have a planet 0.8-1.25 times the size of Earth in an orbit of 85 days or less.

"As far as planets go, Earth-sized planets are very small," Pulliam said. "Jupiter-like planets are easier to find; however, our study finds that the smaller planets are more common."

Using Kepler data, Christopher Burke, a scientist at the SETI Institute, said that 58 planets found so far are believed to be in their host stars' habitable zones -- where any water on them has a chance of being liquid. Planets orbiting close to their suns are likely to be infernos; planets in distant orbits will probably be too icy.

Kepler's mission is to find and document Earth-sized planets at greater distances. The more planets discovered with Earth-like orbits in the habitable zone, the greater the chances of extraterrestrial life.

Copyright 2013 ABC News Radio


Astronomers Discover Habitable Planet Around Nearby Star

Habitable planet orbits Tau Ceti Image credit: J. Pinfield/RoPACS network at the University of Hertfordshire(NEW YORK) -- Perhaps Earthlings aren’t alone in their celestial neighborhood.

An international team of scientists has discovered at least one new habitable planet – and, considering the vastness of space, this planet is fairly close.

A planet with conditions that can sustain life is one of five orbiting a star neighboring the sun, astronomers from the United Kingdom, USA, Chile and Australia recently revealed in an official statement. The star, called Tau Ceti, is located 12 light years away.

In an interview with ABC News, Steven Vogt, a professor at the University of California, Santa Cruz, said he believed there actually might be two planets in the Tau Ceti system with “conditions conducive to life” – though the official announcement described just one.

“In order for a planet to be inhabitable, it should lie in a zone that is neither too hot nor too cold to allow for liquid surface water and, potentially, life,” said Vogt, who was part of the international team that made the discovery.

A planet with a mass approximately five times that of Earth was the smallest planet found to be orbiting in the habitable zone of any Sun-like star, said a statement issued by the team of researchers.

The findings came after almost 14 years of gathering data from more than 6,000 observations from three different telescopes located in Chile, Australia and Hawaii.

“What is unique about this star is it’s amazingly nearby – that you can actually see it with the naked eye,” said Vogt. “There are nearly 18 stars that are this close to us. This is the 19th closest star, and that is why it is special.”

The results of the study followed the use of a new mathematical computational method that employed noise modelling, allowing the team to detect the new planets and their conditions.

“We chose Tau Ceti for this noise modeling study because we had thought it contained no signals,” said Hugh Jones from the University of Hertfordshire. “And as it is so bright and similar to our Sun, it is an ideal benchmark system to test out our methods for the detection of small planets.”

Jones is one of numerous astronomers on the team that also includes James Jenkins from the Universidad de Chile, a visiting fellow at the University of Hertfordshire; Chris Tinney of the University of New South Wales and Mikko Tuomi from the University of Hertfordshire.

Tuomi was the lead mathematician behind the mathematical noise modeling employed in the research.

Other scientists included Paul Butler of Carnegie Institution for Science, Simon O’Toole of the Australian Astronomical Observatory and Brad Carter from the University of Southern Queensland.

John Barnes and David Pinfield were also involved and supported by the University of Hertfordshire.

“This is an exciting study, and we look forward to many more similar findings – as it seems very common that lots of stars have their own planets which we can look into,” Tinney told ABC News.

“The emerging knowledge from this study is that it is almost certain to us now that almost every star has its own planets orbiting around it,” said Vogt. “This means there might be more planets than there are stars.”

Vogt added that even though there are numerous planets with similar habitable conditions, the team’s future strategy would be to focus on those nearest to Earth.

“This is very interesting because it allows for the possibility of sending robotics, sending signals, and have two-way communication with some life that might be out there,” he said.

Copyright 2012 ABC News Radio

ABC News Radio