html) FO Aquarii is in the Aquarius constellation and is made up of a white dwarf star and a companion low-density star - known as an intermediate polar.
A team of University of Notre Dame astrophysicists say they cannot yet explain why an interacting binary star known as the king of the intermediate polars about 500 light-years from Earth appears to be fading.
First identified as a magnetic CV in the late 1980s, V2301 Oph was initially thought to be an intermediate polar
(IP), as observations seemed to show the presence of a small accretion disc.
Based on X-ray observations, they suggested the system might be an intermediate polar.
In this regard it resembles the intermediate polar HT Cam, which shows a fair amount of variability during quiescence.
From unfiltered time resolved photometry, we measured the white dwarf spin period of the intermediate polar 1RXS J063631.
By contrast, in the family of CVs known as Intermediate Polars (IPs), the magnetic field of the white dwarf is sufficient to disrupt the inner portion of the accretion disc.