The largest brown marble in Lindor's hand, Riga is deemed the most interesting of them all. Its size and other observable characteristics make it as interesting as Tylo among Jool's moons. A large portion of its surface even has a subtle but clear familiarity to Kerbin.

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Rational Resources Classification:

Ocean	Surface	Atmosphere	Exosphere
None	Ice-Methane	Ice-Nitrogen	None

From the PDF included in the download:

Bulk Params		Orbital and Rotational Params
Classification	Moon (Lindor)	Semi-major Axis	309,380 km
Radius	750 km sea level, 751.4 km mean	Periapsis	300,099 km
Mass	1.48773×1022 kg	Apoapsis	318,661 km
Gravitational Parameter	9.92923×1011 m3/s2	Orbit eccentricity	0.03
Mean density	8,370 kg/m3	Orbit inclination	0.5°
Surface gravity	0.18 g ASL	Longitude of ascending node	90°
Escape velocity	1,627 m/s	Argument of periapsis	105°
Bond Albedo	0.45	Sidereal orbit period	32.585 days
Solar irradiance	14.8 W/m2	Synodic period	32.684 days
Black-body temperature	77 K	Mean orbital velocity	1,381 m/s
		Sidereal rotation period	32.585 days
		Solar day	32.684 days
		Synchronous orbit altitude	N/A
		Sphere of influence	24,040 km

Atmosphere
Overall height	90 km
Pressure	0.06 atm sea level
Mean temperature	80 K sea level
Mean molecular weight	28 g/mol
Composition	100% N2