2024/07/31 by Andrew Gould, Gould, Andrew
Physics and Astronomy · #Archaeology #Artificial intelligence #Astro and Planetary Science #Astrophysics of Galaxies (astro-ph.GA) #Computer science #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Frontier #Geography #Geology #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Parallax #Planetary Science and Exploration #Space exploration and regulation
paper · pdf · doi:10.48550/arxiv.2407.21696
openalex publication_date 2024/07/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
I show that microlens parallaxes, π\rm E, can be derived for free-floating planets (FFPs) with masses down to that of Pluto, by combining observations from a satellite in geosynchronous (GEO) orbit with another observatory that is on or near Earth's surface, i.e., either ground-based or in low Earth orbit (LEO). Because these low-mass FFPs typically have measurements of the angular Einstein radius, θ\rm E, from finite-source effects, such π\rm E measurements directly yield the FFP mass M=θ\rm E/κπ\rm E where κ is a physical constant. Such Earth-GEO measurements almost perfectly complement Earth-L2 measurements, which extend to higher FFP mass and greater FFP distance. LEO-only observations can yield mass measurement at even smaller FFP mass and nearer FFP distances. I discuss methods for breaking the Refsdal (1966) two-fold degeneracy in π_\rm E,±.