Two Predicted, Concentric Nova Shells Surround the Prototype Dwarf Nova U Geminorum

Michael M. Shara, Kenneth M. Lanzetta, Aayushi Doshi +7

In the 170 years since its discovery, U Gem has been intensively studied as the prototypical cataclysmic binary star. Its massive white dwarf (WD) (~ 1.2 Msun) is cannibalizing its…