Infrared Observations of Novae with SOFIA and Beyond

Thermonuclear runaways (TNRs) on the surfaces of white dwarf (WD) stars accreting matter in close binary systems produce classical nova explosions that may play an important part in producing some of the isotopic anomalies that are present in the remnants of the primitive solar system. We review the use of infrared (IR) photometric and spectroscopic observations to quantify the physical parameters of classical nova outbursts and to assess their contributions to the interstellar medium (ISM) where star formation occurs. Metal abundances in the ejecta can be deduced from dust emission features and metallic forbidden line emission. The observations described here also provide basic information about the TNR that causes the nova explosion, the chemical composition of the WD upon which the TNR occurs, and the nature of the WD’s progenitor star. We show that some recent bright novae have ejected shells that are extremely overabundant in C, N, O, Ne, Mg, Al, and Si. The properties of dust grains produced by novae are reviewed and compared to those of the dust grains observed in preplanetary nebulae and dust grains released from comet nuclei. By analogy to novae, supernovae (both Types I and II) and stellar mergers produce ejecta that enrich the ISM and contribute the building blocks of life and planets to new stellar and planetary systems. We review observations of novae made with the Spitzer Space Telescope and the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA). We anticipate the impact that these observations will have on the definition of proposed FIR Probe missions, such as the PRobe far-Infrared Mission for Astrophysics (PRIMA), that will observe novae, stellar mergers, and supernova explosions.