An international team of scientists, including Carnegie's Paul Butler, has discovered that Tau Ceti, one of the closest and most Sun-like stars, may have five planets. Their work is published by Astronomy & Astrophysics and is available online.
At a distance of twelve light years and visible with a naked eye in the evening sky, Tau Ceti is the closest single star with the same spectral classification as our Sun. Its five planets are estimated to have masses between two and six times the mass of the Earth--making it the lowest-mass planetary system yet detected. One of the planets lies in the habitable zone of the star and has a mass around five times that of Earth, making it the smallest planet found to be orbiting in the habitable zone of a Sun-like star.
The international team of astronomers, led by Mikko Tuomi from the University of Hertfordshire, combined more than six-thousand observations from three different instruments and applied intensive modeling to the data. Using new techniques, the team found a method to find signals half the size previously thought possible, which greatly improves the sensitivity of searches for small planets and suggests that Tau Ceti is not a lone star but has a planetary system.
"We pioneered new data modeling techniques by adding artificial signals to the data and testing our recovery of the signals with a variety of different approaches," Tuomi said. "This significantly improved our noise modeling techniques and increased our sensitivity to find low mass planets."
Tau Ceti was chosen for this noise-modeling study because the team thought it had no signals and would be a good benchmark system to test their methods for planet detection. This is particularly true because it is so bright and similar to our own Sun. It's also one of Earth's nearest cosmic neighbors, so scientists could be able to learn about the atmospheres of these planets in the not-too-distant future.
More than 800 planets have been discovered orbiting other worlds, but planets in orbit the around the nearest Sun-like stars are particularly valuable for research.
"We are now glimpsing for the first time the secrets of our nearest companion stars and their previously hidden reservoirs of potentially habitable planets," Butler said. "This work presages the time when we will be able to directly see these planets, and search them for water, carbon dioxide, methane, and other signposts of life."
Carnegie Institution: http://www.ciw.edu
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Human eyes don't know half of what they're missing. But the Chandra Observatory, with its x-ray vision, gives us a stunning peek.
Astronomers in the US have discovered a distant world with the longest year of any planet outside our Solar System.
The Gaia satellite is being hit by far more micrometeoroids than anticipated, which might spell trouble for spacecraft headed to the same orbital position
On July 20, 1969, Neil Armstrong and Buzz Aldrin became the first two people to land on the lunar surface, while their third crew member, Michael Collins, continued to orbit around the moon. Armstrong and Aldrin arrived in the Lunar Module (LM) Eagle, one of three parts of the Apollo 11 spacecraft which also included…
When scientists looked over the images sent from the Rosetta probe, they found something completely unexpected about its destination
It took 16 years and data from four orbiting spacecraft to assemble, but the U.S. Geological Survey’s new map of Mars is awesome. In beautiful color and excellent detail, the map shows the geology of the Red Planet’s surface today, and reveals a new understanding of its past.
Overcoming two months of delays, a Space Exploration Technologies’ Falcon 9 rocket blasted off from Florida on Monday to put six small commercial communications satellites into orbit for ORBCOMM Inc.
A new study makes it possible for you to hold one of astronomy's great mysteries in your hands—and understand it better too
A future lunar probe could be setting China up for a manned mission next decade.
Deep in the sea or high in the sky? A Russian Soyuz rocket produced this eerie jellyfish-like plume as it climbed up through the thin air of near space