Sunday, March 23, 2014

First Microlensing Detection of a Planet Circling a Brown Dwarf Candidate

First Microlensing Detection of a Planet Circling a Brown Dwarf Candidate:



This artist's conception could resemble a planetary system in front of a background star. Image Credit: NASA Goddard Space Flight Center / Francis Reddy

This artist’s conception could resemble a planetary system in front of a background star. Image Credit: NASA Goddard Space Flight Center / Francis Reddy
When astronomers detect new exoplanets they typically do so using one of two techniques. First, there’s the famous transit technique, which looks for slight dips in light as a planet passes in front of its host star, and second is the radial velocity technique, which senses the motion of a star due to the gravitational pull of its planet.

But then there is gravitational microlensing, the chance magnification of the light from a distant star by the mass of a foreground star and its planets due to the distortion in the fabric of spacetime. While this technique sounds almost improbable, it is so accurate that every detection skips nominating planets as candidates and immediately verifies them as bona-fide worlds.

But without follow-up observations, the microlensing technique struggles with characterizing the incredibly faint host star. Now, a team of international astronomers led by PhD candidate Jennifer Yee from Ohio State University has detected the first microlensing signature, lovingly called MOA-2013-BLG-220Lb, that looks like a confirmed planet orbiting a candidate brown dwarf — an object so faint because it isn’t massive enough to kick-off nuclear fusion in its core.

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Read the rest of First Microlensing Detection of a Planet Circling a Brown Dwarf Candidate (566 words)


© Shannon Hall for Universe Today, 2014. |
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