HD 20781 e is a hot Neptune around the star HD 20781. The planet has a minimum mass of 14.03 Earth masses[4] and it orbits with a semi-major axis of 0.3374 astronomical units and an orbital eccentricity of approximately 0.06.[2][4] With the same composition as Neptune, it would have a radius of 3.79 times that of the Earth. With the same composition as Earth, it would have a radius of 2.08 times that of the Earth. It orbits near the inner edge of the habitable zone of HD 20781.[citation needed]
This planet was initially reported in a 2011 preprint, which referred to it as HD 20781 c.[1] However, the 2017 paper (published in a journal in 2019) that confirmed the planet designated it HD 20781 e, using the c designation for a different, shorter-period planet.[4]
^ abMayor, M.; Marmier, M.; Lovis, C.; Udry, S.; Ségransan, D.; Pepe, F.; Benz, W.; Bertaux, J.-L.; Bouchy, F.; Dumusque, X.; Curto, G. Lo; Mordasini, C.; Queloz, D.; Santos, N. C. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497 [astro-ph.EP].
