Related papers: Novae Ejecta as Discrete Adiabatically Expanding G…
The properties of supernovae (SNe) are reviewed. It is shown that the observed characteristics of the morphological classes of SNe (types Ia, Ib/c, II) can be explained in terms of two basic explosion mechanisms, i.e. core collapse of…
Novae are the observational manifestations of thermonuclear runaways on the surface of accreting white dwarfs (WDs). Although novae are an ubiquitous phenomenon, their properties at low metallicity are not well understood. Using the…
In the favored progenitor scenario, Type Ia supernovae arise from a white dwarf accreting material from a non-degenerate companion star. Soon after the white dwarf explodes, the ejected supernova material engulfs the companion star;…
Fast novae are primarily located within the plane of the Galaxy, slow novae are found within its bulge. Because of high interstellar extinction along the line of sight many novae lying close to the plane are missed and only the brightest…
The outbursts of novae are among the strongest explosions in the Universe. The eruptions involve physical processes that span the whole electromagnetic spectrum, demanding multifrequency observations. The photometric and spectroscopic…
Red novae or luminous red novae are a class of optical transients that have emerged over the past two decades. They occupy an intermediate luminosity regime between classical novae and supernovae and are characterized by cool, slowly…
Novae are now firmly established as a high-energy (>100 MeV) gamma-ray source class by the Fermi Large Area Telescope (LAT). In symbiotic binary systems such as V407 Cyg 2010, there is a firm theoretical framework for the production of…
The rates of SN Ia for double-degenerate and single-degenerate scenario are computed for the models of spiral and elliptical galaxies. The number of nuclearly burning white dwarfs (NBWD) is traced. The data favours double-degenerate…
Classical novae produce radioactive nuclei which are emitters of gamma-rays in the MeV range. Some examples are the lines at 478 and 1275 keV (from 7Be and 22Na) and the positron-electron annihilation emission (511 keV line and a continuum…
The recent GAIA DR2 measurements of distances to galactic novae have allowed to re-analyse some properties of nova populations in the Milky Way and in external galaxies on new and more solid empirical bases. In some cases we have been able…
Some transients, although classified as novae based on their maximum and early decline optical spectra, cast doubts on their true nature and whether nova impostors might exist. We monitored a candidate nova which displayed a distinctly…
A growing number of early Be stars discovered in X-ray surveys exhibit X-ray luminosities intermediate between those of normal stars and those of most Be/X-ray binaries in quiescence. Their X-ray spectra are also much harder than those of…
Classical novae are significant sources of interstellar material, especially carbon, nitrogen and oxygen. These standard candles are only behind supernovae and $\gamma$-ray bursts as the third brightest objects in the sky, and the most…
Peaking at 3.7 mag on 2020 July 11, YZ Ret was the second-brightest nova of the decade. The nova's moderate proximity (2.7 kpc from Gaia) provided an opportunity to explore its multi-wavelength properties in great detail. Here we report on…
In this work we investigate the evolution of the X-ray emission of a cluster of single young massive stars with different metallicities. We have considered the X-ray contribution originated by the diffuse gas heated by the mechanical energy…
Classical novae are thermonuclear explosions that occur on the surfaces of white dwarf stars in interacting binary systems (Bode & Evans 2008). It has long been thought that the luminosity of classical novae is powered by continued nuclear…
We present a novel approach for characterizing nova candidates by exploiting the infrared capabilities of the Wide-field Infrared Survey Explorer (WISE) catalog. We developed a pipeline to identify novae based on well-defined infrared…
The discovery of novae as sources of ~GeV gamma-rays highlights the key role of shocks and relativistic particle acceleration in these transient systems. Although there is evidence for a spectral cut-off above energies ~1-100 GeV at…
A hydrostatic and stationary white dwarf envelope model has been developed for the study of the post-outburst phases of classical novae and their soft X-ray emission. Several white dwarf masses and chemical compositions typical for…
We present a re-analysis of the H$\alpha$ and [OIII] flux data from the only comprehensive study of the luminosity evolution of nova shells, undertaken almost two decades ago. We use newly available distances and extinction values, and…