LP 21 is a sparse, very loose object of very low C3 quality. Its parallax locates it at a large^* distance, near the mid-plane, affected by low extinction. It is catalogued as an intermediate-age cluster (see Parameters). It is rarely studied in the literature, with no articles listed in the last 9 years.

(*): The parallax distance estimate (~5.25 kpc) differs significantly from the median photometric distance (~2.35 kpc).

⚠️ Warning: the low UTI value and no obvious signs of duplication (C_dup=1.0) indicate that this is quite probably an asterism, moving group, or artifact, and not a real open cluster.

Reference	Year	RA [deg]	DEC [deg]	Plx [mas]	pmRA [mas/yr]	pmDE [mas/yr]	Rv [km/s]
UCC	–	339.911	57.626	0.191	-4.058	-2.32	-89.512
Loktin & Popova	2017	339.885	57.606	–	-1.753	-0.583	–

💡 Note: The UCC values are estimated from its identified members.