HD 52721 as a Quadruple System

— We present the study of the multiple system HD 52721 by means of speckle interferometry in 2019–2020 at the 6-m telescope of the SAO RAS. Formerly, HD 52721 was known as triple ( 6.93 (B2V + B2V; P = 1^d.6101570 ) + 7.88 ; 0_.^'65 ). In our work, the system is resolved as a speckle interferometric triple system, i.e., the total system multiplicity increased up to four components ( 6.80 (B2Ve; 1^d.6101570 )+ 8.95 (B9VХ, 0_.^”03 ); 0_.^”64 ). We have used the reference-dependent and reference-independent methods for measuring positional parameters and magnitude differences between the components. The obtained measurements of the brightness differences agree with the observed light curve of the eclipsing pair.