A horde of brown dwarf secondaries in cataclysmic binary systems?

According to The Donor Stars of Cataclysmic Variables, yes. Here I see most of CV secondaries being much below stellar/substellar limit (even <<0.05 M_Sol).

Am I wrong?

Radii, as expected look a bit "bloated" (>>1.5 Rj) due to extreme heating and closeness to degenerate host.
Others seem Jupiter-sized.

An example:

DI UMa has a 0.051 M_Sol companion with radius 0.105 R_Sol (i.e 1.05 Jupiter radii). I think.
EG Cnc's secondary is even less massive (31 Mj) and Saturn-sized (0.95 Rj).

More details in the papers.

Edasich wrote:

... Saturn-sized 0.95 Rj

Saturn's radius is 0.84 Rj. 0.95 Rj is much closer to Jupiter.

This is an interesting paper. What are the odds of a catacysmic variable star's secondary/donor being a planet?

How much of an influence can a planet have on its star?

Given the nature of CV systems, I'm not sure that calling these objects "brown dwarfs" is a particularly helpful way to describe the system, unless you can show that the object was in the substellar regime before the onset of mass transfer.

Ok, but when a low-mass stellar object has lost so much mass to lay in substellar regime and to stop any kind of stellar process, how should we call this object? Surely it could be an "exotic" kind.

It wouldn't be any different than what we find at the SWIFT J1756.9-2508 system, where a pulsar has accreted enough matter from a white dwarf to make the star a 7 Jupiter-mass object.

The object is still considered a star. It seems that what is, and what is not, a planet is considered to be related to how the object formed. The white dwarf at SWIFT J1756.9-2508 and the brown dwarfs at these CV systems may have both been stars, and as such, will probably continue to be considered as such.

Surely "exotic" stars since they cannot burn hydrogen. Only being warmed and ionized due to extreme stellar closeness.

Interesting the fact often such objects do behave like Upsilon Andromedae b, showing dayside warmed and nightside quite cooler.

I've noticed this in this paper concerning LY Aquarii detached system where secondary is an object with 27 Jupiter masses and 0.6 Jupiter radii.

Orbital variability of the PSR J2051-0827 Binary System

Or else this other case:

A Brown Dwarf Companion for the Accreting Millisecond Pulsar SAX J1808.4-3658