Earthlike ‘Planet’ Found to Have Orbit Around Nearby Star
European astronomers reported Thursday the discovery of a rocky “super Earthlike object” orbiting a nearby star much like our own sun.
The discovery of the smallest planet yet detected around another star coupled with a report this week that even modest telescopes can be networked to detect “extra-solar” planets – underscores the quickening pace at which new worlds are swimming into view.
NASA and a team of planet-hunters plan to disclose Tuesday the “discovery of a new class of planets beyond the solar system” the agency says will represent a significant advance in the search for other worlds.
The team is headed by University of California, Berkeley, astronomer Geoffrey Marcy, who is credited with the discovery of at least 60 extra-solar planets.
Including the latest discovery, astronomers have now identified at least 125 planets orbiting other stars, and they say the pace is likely to accelerate as detection methods grow more sophisticated and the number of institutions hunting for them increases.
The latest discovery provides a glimpse of what may lie ahead. Astronomers at the European Southern Observatory in La Silla, Chile, say they have found a rocky planet about 14 times the mass of Earth, orbiting the star mu Arae in the constellation Altar. Earlier observations had identified two larger, gaseous planets there.
“But this new planet appears to be the smallest yet discovered around a star other than the sun,” says Francois Bouchy, a member of the European astronomy team. He says the presence of three distinct planets “makes mu Arae a very exciting planetary system.”
The system is particularly interesting because the star, which is visible to the naked eye in the Southern Hemisphere, closely resembles our sun and lies a mere stone’s throw away in astronomical terms – about 50 light-years, or roughly 300 trillion miles. The sun, by comparison is 93 million miles from Earth.
The newly discovered planet – with a surface temperature that probably exceeds 1,000 degrees and an orbit that circles the parent star once every 9.5 days, still isn’t the Earth-like “blue marble” and potential oasis for life that astronomers one day future telescopes will enable them to see.
But it’s closer. Until now, all of the so-called “exoplanets” have been gaseous giants the size of Jupiter or larger – worlds astronomers say are clearly inhospitable to life as we know it.
So far, no one has actually seen an exoplanet. Because distances are so great and planets, relative to the parent star, are small and dark, astronomers must rely on the subtle wobble in the star’s light caused by the gravitational effects of the planet. It requires big telescopes and repeated observation.
But this week, a team of astronomers from the National Center for Atmospheric Research and other institutions reported the first successful direct detection of a new planet using a network of telescopes no bigger than those many amateurs use in their back yards.
By comparing and combining observations with small telescopes in California, Arizona, Massachusetts and the Canary Islands, the team was able to detect the faint, but periodic dimming of brightness caused by the passage of a Jupiter-sized planet across the face of a bright star in the constellation Lyra.
Other techniques that may aid the search for distant planets are also under development. More than 50 astronomical groups or institutions are currently gearing up – or are already at work – for the expected era of planetary discovery that lies ahead.
mtoner@ajc.com