An exoplanet astronomer has created a GIF that charts 250 years of planet detection in just 60 seconds. It should come as no surprise that the last couple of decades have been rife with exoplanet discoveries as detection technology has advanced. However, the GIF does more than just show the recent exoplanet gold rush, it also compares the size and orbital distance of these planetary discoveries to our own solar system.
“The idea of this plot is to compare our own solar system (with planets plotted in dark blue) against the newly-discovered extrasolar worlds,” wrote Hugh Osborn, the creator of the GIF, on his website. “Think of this plot as a projection of all 1,873 worlds onto our own solar system, with the Sun (and all other stars) at the far left.”
Credit: Hugh Osborn.
Note: The first exoplanets were not discovered in the 1700s. Those dark blue dots are actually solar system planets that have been placed there for comparison. Here is a color cipher to help differentiate between the marks.
- Dark blue: Solar system planets.
- Light blue: RV planets.
- Maroon: Direct Imaging planets.
- Orange: Microlensing discoveries.
- Green: Planets found via the transit method.
The horitzontal axis (x-axis) measures the orbital period of a planet, which is how long it takes for the planet to orbit around its star. The vertical axis (y-axis) is simply the mass of the exoplanet in Earth masses.
Upon closer inspection, a few interesting patterns emerge. For example, the top left is dense with large worlds, or "hot Jupiters." Even though they are relatively rare, they are easy to find because they produce a large radial velocity by orbiting so close to their parent star.
“The bottom group is from the Kepler space telescope," wrote Osborn. "This clustering is the only one that’s actually real and not just a systematic effect. This is because Kepler was capable of finding every type of planet down to ~1 Earth radius. So this clustering shows that there are more Earth and super-Earth sized planets than any other. Hopefully we can begin to probe below it’s limit and into the Earth-like regime, where thousands more worlds should await!"