The planets were found by Australian, American and British astronomers using the Anglo-Australian Telescope in New South Wales and the Keck Telescope in Hawai'i. They employed the "Doppler wobble" technique, which measures how stars are tugged around by their planets' gravity.
Three planets with masses ranging from 5.3 to 24.9 Earth masses orbit the star 61 Virginis, which is virtually a twin of the Sun.
"These planets are particularly exciting," said team member Professor Chris Tinney of the University of NSW. "Neptune in our Solar System has a mass 17 times that of the Earth. It looks like there may be many Sun-like stars nearby with planets of that mass or less. They point the way to even smaller planets that could be rocky and suitable for life."
61 Virginis can be seen with the naked eye. It lies 28 light-years from Earth in the constellation of Virgo, which at this time of year can be seen rising a few hours before the Sun. The findings for 61 Virginis are to be published in The Astrophysical Journal.
The fourth planet the research team found is a Jupiter-mass planet orbiting the Sun-like star 23 Librae. 23 Librae lies 84 light-years away in the constellation of Libra. Another planet was found around this star in 2006: this new one is the second.The new planet has a 14-year orbit. This makes it very like Jupiter, which has a 12-year orbit.
"In fact, what we detect from this star system is very like what we'd detect from our own Solar System if we were observing it from a distance, because Jupiter has the strongest gravitational effect of all our Sun's planets," said Dr Simon O'Toole of the Anglo-Australian Observatory, a member of the planet-hunting team.
"We are now in a position to quantify how common planets like Jupiter are around stars like our Sun," said team member Hugh Jones of University of Hertfordshire. "Compared to the Solar System, most extrasolar systems look odd, with planets in very small or very elliptical orbits. In contrast, this new planet has an orbit that is both large, and nearly circular—and for the first time we are beginning to see systems that resemble our own."
"These detections are truly at the current state-of-the-art," said team member Dr Paul Butler of the Carnegie Institute of Washington, "The inner planet of the 61 Vir system is among the two or three lowest-amplitude planetary signals that have been identified with confidence. We've found there's a tremendous advantage to be gained from combining data from two world-class observatories, and it's clear that we'll have an excellent shot at identifying potentially habitable planets around the very nearest stars within just a few years."
Chris Tinney | EurekAlert!
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
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Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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