The variable YY Draconis was identified by W. Tsesevich in 1934 and determined to be an
Algol type binary that ranged in brightness from apparent magnitude 12.9 to under 14.5 with a period of 4.21123 days. However, subsequent scans of
photographic plates at the same coordinates have failed to identify any such variation. Hence, a positional reporting error is suspected, and no further observations of this variable were reported (as of 1983). In 1982, the
X-ray emission source PG 1148+719 (3A 1148+719) was associated with a star displaying the spectrum of a U Geminorum variable by
R. F. Green and associates. In their paper, they identified this star as YY Dra, based on a positional search of the
General Catalogue of Variable Stars. The following year,
W. Wenzel found the association with YY Dra appeared erroneous but discovered a nearby eruptive variable that brightened to magnitude 10.6 then dimmed to below magnitude 14.5. He estimated a lengthy cycle time of 5 to 20 years, comparable to
BZ Ursae Majoris. This cataclysmic variable was cataloged as DO Draconis. An outburst of DO Dra was observed while in progress in 1985, which brought the system to about a magnitude brighter than minimum. In 1987, a debate arose as to whether this is the same variable as YY Dra, as the coordinates are separated by only . Discussion of this identity conflict has continued as recently as 2022, and, historically, both identifiers have been used to discuss the same cataclysmic variable. A full resolution of this conflict may prove impossible since many of the original photographic plates were destroyed during
World War II. The continued use of DO Dra for this variable has been encouraged since it is an unambiguous identifier. ==Properties==