341520 Mors–Somnus
Mors–Somnus was discovered on 14 October 2007, by American astronomers Scott Sheppard and Chad Trujillo with the Subaru telescope at Mauna Kea Observatories in Hawaii, United States. It was later named after the twins Mors and Somnus from Roman mythology. Orbit and binarity. "Mors–Somnus" is a small double plutino occupying the 3:2 mean motion resonance with Neptune. The object is a wide optically resolved binary with the following orbital parameters: The components has almost equal size. Physical properties. The total mass of the system is . For a realistic minimal density of 0.5 g/cm the  albedo is >0.17 and the size of the components is <60 km. The "Collaborative Asteroid Lightcurve Link" assumes an albedo of 0.1 and calculates a diameter of 175.20 kilometers based on an absolute magnitude of 6.9. "Mors–Somnus" has an ultra-red spectrum in the visible and near-infrared parts of the spectrum. The colors of two components are indistinguishable from each other. It demonstrates a double-peaked light curve with the period of about 9.28 hours and amplitude of 0.24. This indicates that either primary of secondary has an elongated shape and rotates non-synchronuosly. Evolution. The  Mors–Somnus system is likely to be an escaped cold classical Kuiper belt object. Naming. The minor planet was named after the mythological twin Roman gods of death (Mors) and sleep (Somnus). The approved naming citation was published by the Minor Planet Center on 2 June 2015 ().