Related papers: Novae Ejecta as Discrete Adiabatically Expanding G…
The progenitors of Type Ia and some core collapse supernovae are thought to be stars in binary systems, but little observational evidence exists to confirm the hypothesis. We suggest that the collision of the supernova ejecta with its…
Nova Mon 2012 is the third gamma-ray transient identified with a thermonuclear runaway on a white dwarf, that is, a nova event. Swift monitoring has revealed the distinct evolution of the harder and super-soft X-ray spectral components,…
Here we explore the possible preexisting circumstellar debris of supernova type Ia systems. Classical, symbiotic and recurrent novae all accrete onto roughly solar mass white dwarfs from main sequence or Mira type companions and result in…
It has been widely accepted that Type Ia supernovae (SNe Ia) are thermonuclear explosions of a CO white dwarf. However, the natures of the progenitor system(s) and explosion mechanism(s) are still unclarified. Thanks to the recent…
Symbiotic binaries are systems containing white dwarfs (WDs) and red giants. Symbiotic novae are those systems in which thermonuclear eruptions occur on the WD components. These are to be distinguished from events driven by accretion disk…
We have been proposing two evolutionary paths to Type Ia supernovae (SNe Ia), which are called the supersoft X-ray source (SSS) channel and the symbiotic channel, depending on the orbital separation just prior to an SN Ia explosion. The…
In the hard X-ray spectra of some X-ray binaries line features at around 500 keV are detected. We interpret these as arising from pair annihilation in relativistic outflows leading to a significant Doppler shift of the lines' frequencies.…
While type Ia Supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is if there is a non-degenerate companion star at the time of a thermonuclear…
Type Ia supernovae are thought to be thermonuclear explosions of accreting white dwarfs that reach a critical mass limit. Despite their importance as cosmological distance indicators, the nature of their progenitors has remained…
We present multi-epoch near-infrared photo-spectroscopic observations of Nova Cephei 2014 and Nova Scorpii 2015, discovered in outburst on 2014 March 8.79 UT and 2015 February 11.84 UT respectively. Nova Cep 2014 shows the conventional NIR…
While nova eruptions produce some of the most common and dramatic dust formation episodes among astrophysical transients, the demographics of dust-forming novae remain poorly understood. Here, we present a statistical study of dust…
The accretion-induced collapse (AIC) of a white dwarf in a binary with a nondegenerate companion can sometimes lead to the formation of a rapidly rotating and highly magnetized neutron star (NS). The spin-down of this NS can drive a…
Synoptic spectroscopic observations of the U Sco 2010 outburst from maximum light to quiescence as well as a contemporaneous X-ray observation are presented and analyzed. The X-ray spectrum 52 days after outburst indicates a hot source…
Type Ia supernovae, the thermonuclear explosions of white dwarf stars composed of carbon and oxygen, were instrumental as distance indicators in establishing the acceleration of the universe's expansion. However, the physics of the…
This paper is a sequel to an earlier paper devoted to multiple, multicycle nova evolution models (Prialnik & Kovetz 1995, first paper of the series), which showed that the different characteristics of nova outbursts can be reproduced by…
Context. Classical novae are thermonuclear explosions hosted by accreting white dwarfs in stellar binary systems. Material piles up on top of the white dwarf star under mildly degenerate conditions, driving a thermonuclear runaway. The…
Far ultraviolet (FUV) observations are excellent probes of the inner accretion disk, disk outflows, and the mass-accumulating white dwarf in cataclysmic variables. Here we study the contrasting behavior of two canonical dwarf novae in…
New time-resolved optical spectroscopic echelle observations of the nova-like cataclysmic variable RW Sextantis were obtained, with the aim to study the properties of emission features in the system. The profile of the H_alpha emission line…
We present an analysis of the nebular spectra of 103 stripped envelope (SE) supernovae (SNe) collected from the literature and observed with the Subaru Telescope from 2002 to 2012, focusing on [O I] 6300, 6363. The line profile and width of…
The observations of a macronova/kilonova accompanied by gravitational waves from a binary neutron star merger (GW170817) confirmed that neutron star coalescences produce copious ejecta. The coincident gamma-ray detection implies the…