相关论文: Novae Ejecta as Colliding Shells
We have detected coherent oscillations, at multiple frequencies, in the line and continuum emission of the eclipsing dwarf nova V2051 Ophiuchi using the 10m Keck II telescope. Our own novel data acquisition system allowed us to obtain very…
The total masses ejected during classical nova eruptions are needed to answer two questions with broad astrophysical implications: Can accreting white dwarfs be pushed towards the Chandrasekhar mass limit to yield type Ia supernovae? Are…
When the ejecta of supernovae interact with the progenitor star's circumstellar environment, a strong shock is driven back into the ejecta, causing the material to become bright optically and in X-rays. Most notably, as the shock traverses…
Type Ia supernovae (SNe Ia) arise from the thermonuclear explosion in binary systems involving carbon-oxygen white dwarfs (WDs). The pathway of WDs acquiring mass may produce circumstellar material (CSM). Observing SNe Ia within a few hours…
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…
(Abridged) The symbiotic-like binary Mira and nova V407 Cyg was observed in outburst on March 2010 and monitored in several wavelength bands. Here we report on multi-dimensional hydrodynamic simulations describing the 2010 outburst of V407…
Classical novae are powered by thermonuclear runaways that occur on the white dwarf component of close binary systems. During these violent stellar events, whose energy release is only exceeded by gamma-ray bursts and supernova explosions,…
Recent observations by the ROSAT X-ray satellite of the Vela supernova remnant have revealed, in addition to the previously identified compact nebula, a nearly circular emitting region with a radius of about 4 degrees. The Vela pulsar is…
Hydrodynamical interaction of spherical ejecta freely expanding at mildly relativistic speeds into an ambient cold medium is studied in semi-analytical and numerical ways to investigate how ejecta produced in energetic stellar explosions…
Interacting double white dwarf binaries can give rise to a wide variety of astrophysical outcomes ranging from faint thermonuclear and Type Ia supernovae to the formation of neutron stars and stably accreting AM Canum Venaticorum systems.…
Recent observations have revealed that the remnants of stellar-coalescence transients are bipolar. This raises the questions of how these bipolar morphologies arise and what they teach us about the mechanisms of mass ejection during stellar…
The evolution of type Ia supernova binary system progenitors is highly uncertain. Several evolutionary models predict that the accretion of mass onto the white dwarf is accompanied by mass ejection from the binary in the form of a powerful…
There is a consensus that Type-Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise…
Novae, which are the sudden visual brightening triggered by runaway thermonuclear burning on the surface of an accreting white dwarf, are fairly common and bright events. Despite their astronomical significance as nearby laboratories for…
We discuss the nebular phase emission during the 2011 outburst of the recurrent nova T Pyxidis and present preliminary results on the analysis of the line profiles. We also present some discussions about the binary system configurations and…
In recent years, several nova explosions have been detected by Fermi/LAT at E>100 MeV, mainly early after the explosion and for a short period of time. The first evidence of particle acceleration in novae was found in the 2006 eruption of…
Nova super-remnants (NSRs) are substantially extended structures (up to ~130 parsecs across) encompassing recurrent novae. NSRs grow as a result of frequent nova eruptions transporting vast quantities of the locally surrounding interstellar…
Eight X-ray observations of V4743 Sgr (2002), observed with Chandra and XMM-Newton are presented. The nova turned off some time between days 301.9 and 371, and the X-ray flux subsequently decreased from day 301.9 to 526 following an…
We present optical spectra of the ionized `Outer Ejecta' of Eta Carinae that reveal differences in chemical composition at various positions. In particular, young condensations just outside the dusty Homunculus Nebula show strong nitrogen…
We present time-resolved optical spectroscopy of the dwarf nova GW Librae during its rare April 2007 super-outburst and compare these with quiescent epochs. The data provide the first opportunity to track the evolution of the principal…