University of Texas at Austin astronomers William Cochran and Michael Endl, working with graduate students Robert Wittenmyer and Jacob Bean, have used the 9.2-meter Hobby-Eberly Telescope (HET) at McDonald Observatory to discover a system of two Jupiter-like planets orbiting a star whose composition might seem to rule out planet formation. This NASA-funded study has implications for theories of planet formation.
Cochran and Endl have been monitoring the star, HD 155358, since 2001 using the High Resolution Spectrograph on HET. Their measurements of its radial velocity, or motion toward and away from Earth, show that the star has a wobble in its motion, which is caused by unseen companions tugging on the star. HD 155358 is slightly hotter than the Sun, but a bit less massive. Most important, it only contains 20 percent as much of the chemical elements called metals elements heavier than hydrogen or helium as the Sun. Along with one other star (called HD 47536), it contains the fewest metals of any star found to harbor planets. Full article at <http://www.astronomy.com/asy/default.aspx?c=a&id=5575>. -- Ronn! :) _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
