Exoplanet preview from Santorini

Posted by Daniel Pendick
on Tuesday, July 03, 2007

I just caught some hot news about exoplanets on the "Centauri Dreams" blog by Paul Gilster, a veteran science and technology writer and author of Centauri Dreams: Imagining and Planning Interstellar Exploration. If you have never seen Paul's blog, try it. In his own words, it's "a review of research issues in deep space exploration, with an eye toward interstellar possibilities."

On Friday, June 29, Paul reported on some blog postings from astronomer Steinn Sigurðsson (Pennsylvania State University), who attended the "Extreme Solar System" conference June 25 to 29 in Santorini, Greece. The international conference coincided with the 15th anniversary of the discovery of extrasolar Earth-mass planets around a pulsar, PSR 1257+12.

If you want to get the skinny on exoplanets straight from the scientist's mouth, go to Sigurðsson's witty and informative blog, "The Dynamics of Cats." Otherwise, here are some highlights I abstracted from his and Paul's blog postings. You will likely see some of these discoveries and observations covered in future issues of Astronomy:

  • The California and Carnegie Planet Search team has found an exoplanet highly similar to our Jupiter. It orbits a main-sequence dwarf star at a distance of about 4.4 AU, or 4.4 times the distance from Earth to the Sun. Sigurðsson says this system would be an excellent candidate to have rocky, earthlike planets orbiting near their parent stars.
  • Detections of exoplanets around giant stars are increasing rapidly. A Pennsylvania State University survey team announced 30 detections of exoplanets around K stars. (K stars are orangey and cooler than our Sun. Sometimes they are giants, like Arcturus in the constellation Bootes.)
  • An unidentified group of Swiss planet-hunters announced detection of 12 new exoplanets.
  • Discovery of "a couple of more transiting planets," Sigurðsson reports. Transiting planets — where the exoplanet crosses in front of its host star in our line of sight — are uncommon (so far) but very valuable to the study of exoplanets.
  • Rumor has it a paper will appear in a few weeks announcing a "novel planetary system detection," Sigurðsson says.
  • A new project called the Multi-object APO Radial-Velocity Exoplanet Large-area Survey (MARVELS) will survey 10,000 or more stars for planets in 2008-2014.
  • There are "lots of planets around binaries," Sigurðsson says.

Sigurðsson ends his blog postings on this hopeful note: "My sense is that the trend is that we think planetary systems are common, that terrestrial planets are ubiquitous, and that a lot of stars may have reasonable planets persist for a long time in regions where liquid water or other stable chemistry will persist. If life, or intelligent life, is rare, it is probably not for lack of planetary platforms.

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