Nova Mon 2012 as a luminous supersoft X-ray source

Chandra gratings observations of novae in outburst have constrained the models of accreting and hydrogen burning white dwarfs (novae and the possible type Ia progenitors) and are allowing unprecedented discoveries in the nova physics. The supersoft X-ray phase of novae isthe only way to catch a glimpse of the white dwarf itself, when hydrogen burning is still ongoing but only a thin atmosphere sits on top of it. The proposer of this observations has assessed the theoretical prediction that the white dwarf effective temperature is a proxy for the white dwarf mass and this has opened many new possibilities (see Orio 2012, aeXiv 1210.4331). Some novae also show supersoft emission because of very strong emission lines in the ejecta, revealing a whole new physics (see also Orio 2012).This nova is exceptional, it was only one of three detected with the Fermi LAT, and extremely high energy phenomena seem to happen in the ejecta (possibly because of large amounts of circumstellar material).