The astronomers made their announcement on Monday, June 16, 2008, at the international “Extra Solar Super-Earths” conference, between June 16-18, 2008, at Nantes, France.

Team member Michel Mayor, Geneva Obseratory (Switzerland), stated, "We have made very precise measurements of the velocity of the star HD 40307 over the last five years, which clearly reveal the presence of three planets.” LiveScience.com: “Three Super-Earths Found Orbiting One Star”]

Another team member, Stephane Udry (Geneva Observatory), added comments about the overall abundance of other planets, "It is most probable that there are many other planets present: not only super-Earth and Neptune-like planets with longer periods, but also Earth-like planets that we cannot detect yet. Add to it the Jupiter-like planets already known, and you may well arrive at the conclusion that planets are ubiquitous." [LiveScience.com]

The star HD 40307, which is about 80% the mass of the Sun, is located about 41.75 light-years away (12.8 +/- 0.1 parsecs), near the southern constellatons of Doradus and Pictor.

The astrophysics team located the three planets with a technique called radial velocity. The technique looks for miniscule wobbles in the motion of a star. Such a motion reveals that a planet is present because the gravitational force of the planet is pulling at the much larger star.

With the three planets, each, about one hundred thousandth the size of its parent star, the pull is very, very small indeed—and, thus, very difficult to detect by astronomers.

The wobble is a “back-and-forth” motion with a magnitude of about two meters per second. Thus, as the planet orbits the star, it moves the star abnormally within its own orbit.

In fact, David Charboneau (Harvard-Smithsonian Center for Astrophysics), states, “The detection of a triple-SuperEarth system is monumental. First, it demonstrates the remarkable advances in the measurement precision achieved by these cutting-edge instruments. Second, the detection of three presumably rocky planets orbiting a single star is historic since that system really is reminiscent of our own solar system.” [Science News (subscription required): “Otherworldly triple play”]

Mayor comments, "Does every single star harbour planets and, if yes, how many? We may not yet know the answer but we are making huge progress towards it." [ESO: "A Trio of Super-Earths“]

Tags See All Tags

Astronomy  Earth  Exoplanet  Planet  Research  Science  Superearth  William Atkins