For reasons that remain obscure, the planet's thermosphere is at an anomalously high temperature of about 750 K. The planet is too far from the Sun for this heat to be generated by ultraviolet radiation. One candidate for a heating mechanism is atmospheric interaction with ions in the planet's magnetic field. Other candidates are gravity waves from the interior that dissipate in the atmosphere. The thermosphere contains traces of carbon dioxide and water, which may have been deposited from external sources such as meteorites and dust.
What is Neptune's temperature in the thermosphere? 
750 K
For reasons that remain obscure, the planet's thermosphere is at an anomalously high temperature of about 750 K. The planet is too far from the Sun for this heat to be generated by ultraviolet radiation.
For reasons that remain obscure, the planet's thermosphere is at an anomalously high temperature of about seven hundred fifty K. The planet is too far from the Sun for this heat to be generated by ultraviolet radiation.
What is Neptune's temperature in the thermosphere? 