Small Trojan Asteroids Defy Expectations

Understanding the beginning of the solar system requires us to look at some very strange places. One such place is at the so-called “Trojan” asteroids that share Jupiter’s orbit in front of and behind it. But for a long time, these cosmic time capsules have held a mystery for astronomers: why are they color-coded? The populations of larger asteroids are very clear split into two distinct groups - the “reds” and the “less reds”, because apparently they’re all red to some extent. A new paper from researchers in Japan tried to solve this mystery by taking a close look at even smaller asteroids, and their findings, published in a recent edition of The Astronomical Journal, actually brings up a completely different question - why don’t smaller Trojan asteroids have the same color-coding?