Entries by Massimo

The epsilon Eridani Planetary System (R. Hurt SSC/JPL/Caltech)

Today I am making an exception. The image above is not a photo I took. Actually is not even a photo, but an artist’s rendering that Robert Hurt at the Spitzer Space Center has prepared for a press release base on new results I found with my collaborators at NASA and at various universities across the country. The release concerns the planetary system of the nearby star epsilon Eridani. You can read the full press release here and here.

Epsilon Eridani is the closest star to the Sun known to have at least a planet. The star is also known to have a dusty disk generated by the collisions of bodies (like comets and asteroids) in its planetary system (aptly named “debris disk”). By analysing observations obtained with the Spitzer Space Telescope and the Caltech Submillimeter Observatory (think of them as infrared photographs taken with very expensive camera and lenses) we have determined for the first time the detailed geometry of the system.

The disk is actually divided in three rings: two inner rocky belts similar to the asteroid belt in our Solar System, and one outer icy ring similar to the Solar System’s Kuiper belt (the vast region at the periphery of our planetary system which is the reign of bodies like Pluto). Gaps between the three rings suggest the presence of Jupiter-like planets that are maintaining the structural integrity of the ring system through gravitational interactions. One of these planets have actually been indirectly detected in previous studies. Our detection of an asteroid belt in its close proximity strongly constrains its orbit, perhaps making possible the existence of terrestrial planets orbiting inside the belt. If this will turn out to be true it would be especially exciting, because these inner planets would be in the habitable zone of the star.