Protos is asteroid #52228 and also known as 1977 RN. Protos is of the type A. Protos’ orbit is characterized by a semi-major axis of 3.21 Astronomical Units, an eccentricity of 0.12, a period of revolution of 2 097 days, and an inclination of 27.9 degrees. This orbit is like the orbit of a comet with short periods from the Jupiter group because the Jupiter Tisserand invariant (I too didn’t know this technical term until now) of Protos equals 2.99 and so is greater than two, but lesser than three. The Tisserand invariant is a number, which is calculated from orbital elements to the purpose to distinguish comets from asteroids and to identify periodic comets. The Tisserand invariant is calculated in relation to the orbit of a planet and this planet can be chosen freely. Jupiter is chosen most often and here too, hence the name Jupiter Tisserand invariant. Neptune also is frequently chosen if the object in question is a Kuiper Belt Object. Protos was discovered by the German astronomer Lutz Dieter Schmadel at the La Silla Observatory.

From Lutz Dieter Schmadel is a book, that explains the names of the asteroids. So the names of his own asteroid discoveries should be explained best. Protos is named after the Ancient Greek word protos (πρῶτος). This means first. Like for example also in the name of the asteroid Protogeneia. The name Protos was chosen because #52228 was Lutz Schmadel’s first asteroid discovery.

Hence 1977 RN indicates that something was there before something else. This needs to be compared with and distinguished from asteroids with similar meanings. These are mainly the asteroid Protogeneia and the asteroid Prime.