This work isn't possible without contributions and support from many great collaborators (including high school and undergrad students!). Thanks to JP Beaulieu, Dave Bennett, Euan Hamdorf, @aacole42.bsky.social, Viv Chaudhry, Jessica Lu, Clement Ranc, Katie Vandorou, and many others.

But why not one perfect solution? This is where we come full-circle ⭕- back to the poor sampling of the light curve, but there are also some remaining degeneracies (which plagues microlensing!). High-res imaging is powerful, but it doesn't make life perfect.

So we've fully ruled out any possibility that the lens host is a brown dwarf. The planet is also a bit more massive than the previous studies but it's still very likely a super-Earth. We've reduced the possible solutions by a factor of 2.

With these direct measurements of the lens object in the Keck and Hubble data, we now have strong confidence that the lens host is a star with ~0.3 times the mass of the Sun. The mass of the planet orbiting this star is in the super-Earth regime. The lens distance is ~2kpc.

This measurement of the lens object gives a definitive answer for its mass and distance. We used the Keck and Hubble telescopes many years after the microlensing event to get images like the one here showing a classic 'dipole' feature when we subtract one-star from the image.

With enough patience, we can wait several years for the lens star (or brown dwarf or whatever it is) to separate from the background source star. We can then attempt to image the target(s) with big telescopes and directly measure light from the lens.

Since the 2008 paper and a follow-up in 2012, we've been stuck with at least 8 solutions for this event, but is there a way to do better and rule out more possible solutions? (spoiler: yes!)

Because there is only MOA/OGLE data, the light curve is sparse and poorly sampled, which complicates the modeling of this event. The original studies report many possible solutions (models) that explain the data. Some early solutions even gave a planet orbiting a brown dwarf!

Back in 2008 this was the fourth published microlensing exoplanet, and the first published planet using data from *only* the MOA/OGLE telescopes. Usually a larger network of telescopes gather data for these events, but for many reasons it wasn't the case for this planet.