HD 10180 c is an exoplanet approximately 130 light-years away in the constellation Hydrus.^[2] It was discovered in 2010 using the radial velocity method.^[2] With a minimum mass comparable to that of Neptune,^[3] it is of the class of planets known as Hot Neptunes.^{[citation needed]} Dynamical simulations suggest that if the mass gradient was any more than a factor of two, the system would not be stable.

HD 10180 c

Orbits of the inner planets of the HD 10180 planetary system, using the orbital configuration from an eight-body (the star and seven planets) Newtonian model taking into account tidal dissipation.
Discovery
Discovery date	24 August 2010
Orbital characteristics
Semi-major axis	0.0641 ± 0.0010 AU (9,590,000 ± 150,000 km)
Eccentricity	0.073±0.031[1]
Orbital period (sidereal)	5.75969±0.00028 d[1]
Average orbital speed	136
Argument of periastron	328±24
Star	HD 10180
Physical characteristics
Mass	>0.0416±0.0014 MJ

While planet c does not exist in any mean motion resonances, both planets with adjacent orbits (b and d) share near resonances with c.^{[citation needed]}