New SETI survey focuses on Kepler’s top Earth-like planets
http://www.dearastronomer.com/
With the Kepler mission currently boasting over 1,200 planetary candidates, researchers at UC Berkeley have begun a search for radio signals emanating from any of the candidates.
On May 8th, the team used the Robert C. Byrd Green Bank Telescope for an hour to study eight stars with planetary candidates. The goal is to acquire twenty four hours of data on over 80 planetary candidates – specifically those thought to be in the host star’s habitable zone (where liquid water could exists on a planetary surface). Once the initial research is complete, the research team will perform a rough analysis before enlisting the help of SETI@home users to perform additional analysis.
“It’s not absolutely certain that all of these stars have habitable planetary systems, but they’re very good places to look for ET,” said UC Berkeley graduate student Andrew Siemion. Dan Werthimer, chief scientist for SETI@home adds, “We’ve picked out the planets with nice temperatures – between zero and 100 degrees Celsius – because they are a lot more likely to harbor life…”
Aside from leading a 30 year old SETI project using the Aricebo receiver in Puerto Rico, Werthimer was a researcher involved with a previous project using the previous Green Bank telescope, which collapsed in 1988, and the Allen Telescope Array (ATA) , which went into hibernation mode last month after funding to run the ATA ran out. “With Arecibo, we focus on stars like our sun, hoping that they have planets around them that emit intelligent signals,” Werthimer said. “But we’ve never had a list of planets like this before.”
Since the Arecibo dish cannot view the location of the sky on which Kepler focuses, the Green Bank telescope offers advantages over Arecibo. The SETI UC Berkeley’s SETI observations are “piggybacked” on other operations at Arecibo, and are limited in the frequencies the dish can observe.
Werthimer adds, “Searching for ET around the 21 centimeter line works if civilizations are broadcasting intentionally, but what if planets are leaking signals like ‘I Love Lucy’? With a new data recorder on the Green Bank telescope, we can scan a 800 megaHertz range of frequencies simultaneously, which is 300 times the range we can get at Arecibo.” Given the advantages of the Green Bank telescope, the data collected can, in one day, rival nearly a year’s worth of data collected from Arecibo.
“It’s also great that we will completely span the water hole, a canonical place to look for intentional signals from intelligent civilizations,” Siemion said. What makes the “water hole” significant to researchers is that it is bounded on one end by the 21 cm emissions from neutral hydrogen and on the other by the 18 cm emissions from the hydroxyl ion (OH). Based on our current assumptions that life requires water, and water is made from hydrogen and hydroxyl ( H and OH), the water hole is a favorite of SETI projects. “This is an interesting place, perhaps a beacon frequency, to look for signals from extraterrestrial civilizations,” Siemion added.
Kepler team member and UC Berkeley Astronomy professor Geoffrey March assisted the SETI team with their selection of 86 stars that were chosen from the 1,235 candidate planetary systems. The targets include 54 candidates identified by Kepler as being in the “habitable zone” and range from nearly Earth-sized to larger than Jupiter. The team also included in their list objects with orbits of less than 3 A.U (Distance of Earth’s orbit from our Sun) as well as systems with four or more planetary candidates. Once the Green Bank telescope targets each star, it will also scan the entire Kepler survey area for signals from systems other than the initial 86 targets. Werthimer adds, “If you extrapolate from the Kepler data, there could be 50 billion planets in the galaxy. It’s really exciting to be able to look at this first batch of Earth-like planets.”
The Green Bank telescope is operated by the National Radio Astronomy Observatory, with funds provided by the National Science Foundation (NSF). SETI@home is supported by NSF, NASA and private donations.
Source:EurekAlert/University of California – Berkeley Press Release>
Ray Sanders is a Sci-Fi geek, astronomer and blogger. Currently researching variable stars at Arizona State University, he writes for Universe Today, The Planetary Society blog, and his own blog, Dear Astronomer
2012-12-04 08:06:01
Source: http://www.dearastronomer.com/2011/05/17/new-seti-survey-focuses-on-keplers-top-earth-like-planets/
Source:
