A multiplanet system of super-Earths orbiting the brightest red dwarf star GJ 887

Jeffers, S. V.; Dreizler, S.; Barnes, J. R.; Haswell, C. A.; Nelson, R. P.; Rodríguez, E.; López-Gonz′lez, M. J.; Morales, N.; Luque, R.; Zechmeister, M. et al.
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The closet exoplanets to the Sun provide opportunities for detailed characterization of planets outside the Solar System. We report the discovery, using radial velocity measurements, of a compact multiplanet system of super-Earth exoplanets orbiting the nearby red dwarf star GJ 887. The two planets have orbital periods of 9.3 and 21.8 days. Assuming an Earth-like albedo, the equilibrium temperature of the 21.8-day planet is ~350 kelvin. The planets are interior to, but close to the inner edge of, the liquid-water habitable zone. We also detect an unconfirmed signal with a period of ~50 days, which could correspond to a third super-Earth in a more temperate orbit. Our observations show that GJ 887 has photometric variability below 500 parts per million, which is unusually quiet for a red dwarf.