Extrasolar Planet Spotted Thanks To Dust Clumps

wishus writes "Looking for clumps in the dust around a star allows astronomers to find new planets, like this one, that would be undetectable by gravitational wobble methods."

Comments

The source for the observations in the article

[dpp]

The image of the dust around Epsilon Eridani shown in the article is a false colour submillimetre wavelength image made with SCUBA on the James Clerk Maxwell Telescope in Hawaii. The work described here seems to be computer simulations which tie in with the observations.

You can find out more about those observations of Eps Eri, and of similar evidence for extrasolar planets around Vega and Fomalhaut at the Joint Astronomy Centre, who run the JCMT and for whom I work.

These are the same sort of observations that revealed the 'wake' around Fomalhaut that was covered recently here on Slashdot in 'Looking for intelligence'.

Epsilon Eridani also has Jupiter-sized planet

[Simon Field]

.

There were earlier reports of a "Jupiter-like" planet around this star (see "http://stardate.utexas.edu/pr/pages/20000807.html ").

That planet had a 7 year orbit, was about the size of Jupiter, and was about as far away from its sun as our ateroid belt is from our sun.

Epsilon Eridani is about a billion years old, so the dust has not had a lot of time to be collected by planets, but it is possible that the level of bombardment by comets has settled down to where bacteria-like life could exist on a planet closer to the star.

The authors of the paper linked above speculated on a second planet based on dust ring evidence:

Asymmetric, primordial dust rings made up of 1-mm-size particles extend 60 AU from Epsilon Eridani. The irregular shape of this ring may be due to another, undiscovered planet. "If there is indeed a second planet, the asymmetry of the disk would suggest that the planet is orbiting just inside the ring, at a distance of 30 AU -- much farther out than the planet we have found and with a much longer orbital period than the one we've discovered," according to Hatzes. "Thus, it might also be responsible for the possible overall slope in our velocity measurements. And where there's one planet, there may be more."

The discovery of the planet around Epsilon Eridani raises the likelihood of detecting planets with longer orbital periods and multiplanet systems like our own. "Given its close proximity to Earth, a one-arcsecond separation between the planet and its central star, and the relatively large degree of perturbation -- about 1.4 milli-arcseconds -- of the star from its orbiting planet mean that we could very likely resolve the true mass of this planet, using both direct imaging and space-based astrometric measurements with Hubble Space Telescope," Cochran noted.

Another good source of more information is: http://www.solstation.com/stars/eps-erid.htm.