9799 Thronium, provisional designation: 1996 RJ, is a large Jupiter trojan from the Greek camp and the parent body of a small, unnamed asteroid family (006), approximately 68 kilometers (42 miles) in diameter.
It was discovered on 8 September 1996, by American astronomer Timothy Spahr at the Catalina Station of the Steward Observatory near Tucson, Arizona, in the United States.
[15] On 14 May 2021, the object was named by the Working Group for Small Bodies Nomenclature (WGSBN), after the ancient Greek city of Thronium.
[4] Nesvorný does not give an overall spectral type for this unnamed family, but derives an albedo of 0.06 (see below), which is also typical for carbonaceous C-types.
[14]: 23 In October 2009, a rotational lightcurve of 1996 RJ was obtained from photometric observations by Stefano Mottola using a 1.2-meter telescope at the Calar Alto Observatory in Spain.