Among quadruples or higher multiplicity stars , only a few doubly eclipsing binary systems have been discovered .
They are important targets to understand the formation and evolution of multiple stellar systems because we can obtain accurate stellar parameters from photometric and spectroscopic studies .
We present the observational results of this kind of rare object 1SWASP J093010.78+533859.5 , for which the doubly eclipsing feature had been detected previously from the SuperWASP photometric archive .
Individual PSF photometry for two objects with a separation of about 1.9 arcsec was performed for the first time in this study .
Our time-series photometric data confirms the finding of Lohr et al .
( 29 ) that the bright object A is an Algol-type detached eclipsing binary and the fainter B is a W UMa-type contact eclipsing .
Using the high-resolution optical spectra , we obtained well-defined radial velocity variations of system A .
Furthermore , stationary spectral lines were detected that must have originated from a further , previously unrecognized stellar component .
It was confirmed by the third object contribution from the light curve analysis .
No spectral feature of the system B was detected , probably due to motion blur by long exposure time .
We obtained the binary parameters and the absolute dimensions of the systems A and B from light curve synthesis with and without radial velocities , respectively .
The primary and secondary components of system A have a spectral type of K1 and K5 main sequences , respectively .
Two components of system B have nearly the same type of K3 main sequence .
Light variations for both binaries are satisfactorily modeled by using two-spot models with one starspot on each component .
We estimated the distances to systems A and B individually .
Two systems may have similar distances of about 70 pc and seem to be gravitationally bound with a separation of about 130 AU .
In conclusion , we suggest that 1SWASP J093010.78+533859.5 is a quintuple stellar system with a hierarchical structure of a triple system A ( ab ) c and a binary system B ( ab ) .