Lick Object of 1921

The Lick Object of 1921 is an unidentified astronomical object that was observed from the Lick Observatory in August 1921. Although follow-up observations were not successfully conducted, it is hypothesized that this object is highly likely a non-periodic comet.^[2]

X/1921 P1 (Lick)

Discovery[1]
Discovered by	William W. Campbell
Discovery site	Lick Observatory
Discovery date	7 August 1921
Orbital characteristics[2]
Observation arc	1 day
Perihelion	~0.25 AU
Physical characteristics[3]
Apparent magnitude	–2.0 (1921 apparition)

Observational history

William Wallace Campbell reported the sighting of a star-like object about three degrees from the Sun on the evening of 7 August 1921.^[4][1] Observers noted that the object was as bright as Venus, reaching an apparent magnitude of –2 at its maximum.^[3] A possibility that it was a nova explosion was ruled out due to its high relative position (about 40 degrees) to the Galactic plane.^[a]

Zdenek Sekanina and Rainer Kracht published a study in 2016 where they concluded that the Lick object is highly likely a fragment of the same parent body as the comet C/1847 C1 (Hind).^[2] Their findings suggested that the Lick Object and C/1847 C1 splitted from a parent body sometime during their perihelion on the 7th millennium BC at a relative velocity of ~1.0–1.5 m/s (3.3–4.9 ft/s).^[2]