(Photo courtesy: NASA/JPL-Caltech)

The unique 55 Cancri system, located 41 light-years away in the direction of the constellation Cancer, is notable also because its clutch of four inner planets and one giant outer planet somewhat resembles our own solar system, though without known analogs of Earth or Mars. According to Debra Fischer, lead author and Assistant Professor of Astronomy at San Francisco State University, the fifth planet is within the star’s habitable zone in which water could exist as a liquid.

Finding the five planets circling 55 Cancri took 18 years of continuous research using the Shane telescope at Lick Observatory in northern California and the W. M. Keck Observatory in Hawaii. The critical spectrometers on both telescopes were designed and built by Steve Vogt, Professor of Astronomy at the University of California, Santa Cruz. The finding coincides with the California and Carnegie Planet Search Team’s 20th anniversary of their first attempts to find extrasolar planets by analyzing the wobbles they cause in their host star. Butler and University of California, Berkeley, Professor of Astronomy Geoffrey Marcy began observations of nearby stars at the University of California Lick Observatory in 1987.

Research was funded by NASA and the National Science Foundation, and the paper detailing the work has been accepted for publication in the Astrophysical Journal. For more information click on UC Berkeley News, Science Daily, the Washington Post, and NSF News.

[The photo is an artist's concept of the star 55 Cancri showing the newly discovered planet in the foreground – a gas giant half the mass of Saturn – and three already known inner planets (the planet farthest from the star is not pictured). All the inner planets are the size of Neptune or larger, unlike our solar system's rocky inner planets. The colors of the planets in this illustration were chosen to resemble those of our own solar system. Astronomers do not know what the planets look like.]