Variability
BX Andromedae, like all Beta Lyrae variables, shows a primary and a secondary minimum when, respectively, the most luminous and the less luminous component of the pair is eclipsed by the other. The brightness however changes smoothly, so it's difficult to define an onset and an end time for the eclipses. This cycle repeats approximately every 14.6 hours.
System
The two stars in the system are orbiting so close to each other that they retain an ellipsoidal shape. The spectrum of the two stars hasn't been separated yet; as a whole, the system has a spectral type F2V.[ The physical parameters of the stars (like mass, radius, and temperature) can be inferred from the light curve.]
BX Andromedae, however, may be a quadruple system. This system shows slight orbital period variations that could be induced by a third faint body in the system with an orbital period of 62 years.[22] There is also a visual companion star TYC 2833-53-1 of 10.85 magnitude only 20 arcseconds away with a common proper motion and a distance (measured with parallax) compatible with the one of BX Andromedae, and has an estimated mass of 1.04 {{solar mass}}.[23]
References
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4. ^1 {{citation | last1=Gontcharov | first1=G. A. | title=Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system | journal=Astronomy Letters | postscript=. | volume=32| issue=11| pages=759–771| date=November 2006 | doi = 10.1134/S1063773706110065| bibcode=2006AstL...32..759G |arxiv = 1606.08053 }}
5. ^1 2 {{cite journal | title=A Study of Contact Binaries with Large Temperature Differences between Components | last1=Siwak | first1=M. | last2=Zola | first2=S. | last3=Koziel-Wierzbowska | first3=D. | journal=Acta Astronomica | volume=60 | issue=4 | pages=305–336 | year=2010 | bibcode=2010AcA....60..305S}}
6. ^1 {{cite journal | title=Contact Binaries with Additional Components. I. The Extant Data | last1=Pribulla | first1=T. | last2=Rucinski | first2=S. M. | journal=The Astronomical Journal | volume=131 | issue=6 | pages=2986–3007 | year=2006 | bibcode=2006AJ....131.2986P}}
7. ^1 Database entry, Updated Multiple Star Catalog (MSC, 2018), A. Tokovinin CDS ID J/ApJS/235/6 Accessed on line 2018-10-29.