Title: Evidence for 9 planets in the HD 10180 system Authors: Mikko Tuomi
We re-analyse the HARPS radial velocities of HD 10180 and calculate the probabilities of models with differing numbers of periodic signals in the data. We test the significance of the seven signals, corresponding to seven exoplanets orbiting the star, in the Bayesian framework and perform comparisons of models with up to nine periodicities. We use posterior samplings and Bayesian model probabilities in our analyses together with suitable prior probability densities and prior model probabilities to extract all the significant signals from the data and to receive reliable uncertainties for the orbital parameters of the six, possibly seven, known exoplanets in the system. According to our results, there is evidence for up to nine planets orbiting HD 10180, which would make this this star a record holder in having more planets in its orbits than there are in the Solar system. We revise the uncertainties of the previously reported six planets in the system, verify the existence of the seventh signal, and announce the detection of two additional statistically significant signals in the data. If of planetary origin, these two additional signals would correspond to planets with minimum masses of 5.1^{+3.1}_{-3.2} and 1.9^{+1.6}_{-1.8} Earth masses on orbits with 67.55^{+0.68}_{-0.88} and 9.655^{+0.022}_{-0.072} days periods (denoted using the 99% credibility intervals), respectively.
Astronomers using ESO's world-leading HARPS instrument have discovered a planetary system containing at least five planets, orbiting the Sun-like star HD 10180. The researchers also have tantalising evidence that two other planets may be present, one of which would have the lowest mass ever found. This would make the system similar to our Solar System in terms of the number of planets (seven as compared to the Solar System's eight planets). Furthermore, the team also found evidence that the distances of the planets from their star follow a regular pattern, as also seen in our Solar System. The team of astronomers used the HARPS spectrograph, attached to ESO's 3.6-metre telescope at La Silla, Chile, for a six-year-long study of the Sun-like star HD 10180, located 127 light-years away in the southern constellation of Hydrus (the Male Water Snake). HARPS is an instrument with unrivalled measurement stability and great precision and is the world's most successful exoplanet hunter. Read more
Astronomers have discovered a planetary system containing at least five planets that orbit a star called HD 10180, which is much like our own Sun. The star is 127 light years away, in the southern constellation of Hydrus. The researchers used the European Southern Observatory (Eso) to monitor light emitted from the system and identify and characterise the planets. They say this is the "richest" system of exoplanets - planets outside our own Solar System - ever found. Read more
Astronomers using ESO instruments have discovered a remarkable extrasolar planetary system that has some striking similarities to our own Solar System. At least five planets are orbiting the Sun-like star HD 10180, and the regular pattern of their orbits is similar to that observed for our neighbouring planets. One of the new extrasolar worlds could be only 1.4 times the mass of the Earth, making it the least massive exoplanet ever found.
This video podcast explains how these faraway planets were detected and exactly what we know about them.
European astronomers on Tuesday said they had found a distant star orbited by at least five planets in the biggest discovery of so-called exoplanets since the first was logged 15 years ago. The star is similar to our Sun and its planetary lineup has an intriguing parallel with own Solar System, although no clue has so far been found to suggest it could be a home from home, they said. The star they studied, HD 10180, is located 127 light years away in the southern constellation of Hydrus, the male water snake, the European Southern Observatory (ESO) said in a press release. Read more
Discovery of a new planetary system similar to the Solar System
A group of European astronomers has discovered a planetary system with at least five planets, but it could have two more, around a sun-like star, HD 10180. The number of planets and their distances from the star makes this system resembles the Solar System. The new system resembles the Solar System in the amount of planets (though they are seven instead of eight). In addition, the distances of the planets to their stars follow a regular pattern (seem to follow the Titius-Bode law ), which is also observed in our Solar System. Read more (Spanish)