1727 Mette

1727 Mette, provisional designation, is a binary Hungaria asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 9 kilometers in diameter.

It was discovered on 25 January 1965, by Irish astronomer David Andrews at Boyden Observatory near Bloemfontein in Free State, South Africa. It was named after the discoverer's wife Mette Andrews.

Classification and orbit
The S-type asteroid is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It is also a Mars-crossing asteroid, a dynamically unstable group between the main belt and the near-Earth populations.

It orbits the Sun in the inner main-belt at a distance of 1.7–2.0 AU once every 2 years and 6 months (922 days). Its orbit has an eccentricity of 0.10 and an inclination of 23° with respect to the ecliptic. Being a Mars-crosser, Mette will make a relatively close approach to Mars on April 15, 2023, when it will pass near the Red Planet at a distance of less than 0.08 AU. It was first identified as at Goethe Link Observatory in 1955, extending the body's observation arc by 10 years prior to its official discovery observation.

Physical parameters
A large number of rotational lightcurves of Mette were obtained from photometric observations. They gave a rotation period of approximately 2.981 hours (best rated results) with a brightness variation between 0.22 and 0.38 magnitude, indicating a moderately elongated body (U=3/3/3). The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.97 kilometers, while observations with the Wide-field Infrared Survey Explorer gave a diameter of 5.44 kilometers and an albedo of 0.544.

Naming
This minor planet was named by the discoverer after his wife, Mette Andrews for her comprehension of his nocturnal working hours and absence from home. The approved naming citation was published by the Minor Planet Center on 1 February 1980 (M.P.C. 5183).

Moon
In 2013, a satellite orbiting the asteroid was discovered. The moon measures about 2 kilometers in diameter and orbits Mette once every 20 hours and 59 minutes.

There are several hundreds of asteroids known to have satellites (also see Category:Binary asteroids).