Ob is asteroid #16563 and also known as 1992 BF₂. Ob’s orbit is characterized by a semi-major axis of 3.13 Astronomical Units, an eccentricity of 0.10, a period of revolution of 2’020 days, and an inclination of twelve and a half degrees. Ob measures 16 km in diameter. Ob was discovered by the Belgian astronomer Eric Walter Elst at the La Silla Observatory, a Chilean observatory, which belongs to the European Southern Observatory (ESO).

Ob in 2006 got named after the Russian river Ob (Обь). This seemingly due to confounding it with the Russian river Irtish (Иртыш), on which Joseph-Nicolas Delisle traveled in April 1740 to observe a transit of Mercury. The Ob River however originates in the south of Siberia by the Biya (Би́я) River conjoining with the Katun (Катунь) River near the city Biysk (Бийск) in the Altai (Алтай) Region. The Ob (Обь) River then flows for 3650 km through the west of Siberia before it discharges into the Kara Sea, which belongs to the Arctic Ocean. The Ob (Обь) River has, due to several small ethnic minorities living in Siberia, several other names with different meanings. The Irtish (Иртыш) River is a left tributary of the Ob (Обь) River. The meaning of the name Ob (Обь) is unknown, but “water” is a likely meaning, not only because of suggested etymologies, but also because some of its other names also mean water. The Ob (Обь) River together with its tributaries is the world’s seventh-longest river system and the westernmost of three great Siberian rivers. The Trans-Siberian Railway crosses the Ob (Обь) River at Novosibirsk (Новосибирск). The Ob (Обь) River’s lower stretch carries ice most days of the year, this in spring, when the upper stretch already is molten completely, impounds water, so that big floods would follow if the Russians wouldn’t frequently explode the ice dams.

Due to the reason for the choice of the name, the asteroid Ob is one of Mercury’s helpers. The asteroid Ob due to its name, that is void of fantasy, represents water. Then Ob also hints to West Siberia and especially to the waterways of West Siberia.