An international team of astronomers, including five Carnegie scientists, reports the discovery of two new planets orbiting a very old star that is near to our own Sun. One of these planets orbits the star at the right distance to allow liquid water to exist on its surface, a key ingredient to support life.
Monthly Notices of the Royal Astronomical Society
Kapteyn’s Star, named after the Dutch astronomer, Jacobus Kapteyn, who discovered it at the end of the 19th century, is the second fastest-moving star in the sky and belongs to the Galactic halo, an extended group of stars orbiting our Galaxy on very elliptical orbits. With a third of the mass of the Sun, this red-dwarf can be seen with an amateur telescope in the southern constellation of Pictor.
The astronomers–including Carnegie’s Pamela Arriagada, Paul Butler, Steve Shectman, Jeff Crane, and Ian Thompson–used new data from the HARPS spectrometer at the European Southern Observatory’s La Silla observatory, the Planet Finding Spectrometer at the Magellan/Las Campanas Observatory in Chile, and the HIRES spectrometer at the W.M. Keck Observatory in Hawaii to measure tiny periodic changes in the motion of the star. The Doppler Effect enabled the scientists to deduce some properties of these planets, including their masses and orbital periods. Continue reading