Related papers: Angular Expansion of Nova Shells
The distribution of ejecta in young supernova remnants offers a powerful observational probe of their explosions and progenitors. Here we present a 3D reconstruction of the ejecta in SNR 0540-69.3, which is an O-rich remnant with a pulsar…
The Type Ib/c supernova SN 2001em was observed to have strong radio, X-ray, and Halpha emission at an age of about 2.5 yr. Although the radio and X-ray emission have been attributed to an off-axis gamma-ray burst, we model the emission as…
We report on recent optical observations of the stellar and the nebular remnants of 22 southern post-novae. In this study, for each of our targets, we obtained and analysed long-slit spectra in the spectral range 3500-6600 A and in…
Using recently acquired HST NIR observations (J, Pa$\beta$ and H bands) of the nearby galaxy NGC1313, we investigate the timescales required by a young star cluster to emerge from its natal cloud. We search for extincted star clusters,…
We extend our initial study of diffusive nuclear burning (DNB) for neutron stars (NSs) with Hydrogen atmospheres and an underlying layer of proton capturing nuclei. Our initial study showed that DNB can alter the photospheric abundance of…
The extended nebulae formed as pulsar winds expand into their surroundings provide information about the composition of the winds, the injection history from the host pulsar, and the material into which the nebulae are expanding.…
We present new narrow-band Ha, [N II], and [O III] high-resolution images of the quadrupolar planetary nebula (PN) NGC 6309 that show in great detail its bipolar lobes and reveal new morphological features. New high- and low-dispersion…
RX Pup is a symbiotic binary which experienced a nova outburst in the 1970's. Here we report a discovery of a ~1300 year old nova shell around the system and a possible detection of a ~7000 year old nova shell. Together with the nova shell…
Many current stellar evolution models assume some dependence of the strength of convective core overshooting on mass for stars more massive than 1.1-1.2 solar masses, but the adopted shapes for that relation have remained somewhat arbitrary…
A new class of core-collapse supernovae (SNe) has been discovered in recent years by optical/infrared surveys; these SNe suggest the presence of one or more extremely dense (~10^5-10^11 cm^-3) shells of circumstellar material (CSM) on…
We report on the spectral evolution of 6 classical novae, V1186 Sco, V2540 Oph, V4745 Sgr, V5113 Sgr, V458 Vul, and V378 Ser, based on the low-resolution spectra obtained at the Fujii-Bisei Observatory and the Bisei Astronomical…
We report the radio detection of a shell-like HI structure in proximity to, and probably associated with, the nova V458 Vul. High spectral resolution observation with the Giant Metrewave Radio Telescope has made it possible to study the…
The nature of ultracompact H II regions (UCHRs) remains poorly determined. In particular, they are about an order of magnitude more common than would be expected if they formed around young massive stars and lasted for one dynamical time,…
We combine Gaia DR3 5-parameter astrometry with calibrated radial velocities for 23 nearby (<1 kpc) young (<60 Myr) clusters, with membership lists from Cantat-Gaudin et al. (2020). We characterise the plane-of-sky structure of the clusters…
In a multi-wavelength survey of $13$ quasars at $5.8\lesssim z\lesssim6.5$, that were pre-selected to be potentially young, we find five objects with extremely small proximity zone sizes that may imply UV-luminous quasar lifetimes of…
We inform on the progress of our on-going project to identify and classify old classical novae, using deep UBVR photometry and subsequent spectroscopy for a proper candidate confirmation, and time-resolved observations in order to find the…
Nova Cen 2013 (V1369 Cen) is the fourth bright nova observed panchromatically through high resolution UV+optical multi epoch spectroscopy. It is also the nova with the richest set of spectra (both in terms of data quality and number of…
Novae are thermonuclear explosions on the surface of accreting white dwarfs and are key laboratories for studying explosive nucleosynthesis, particle acceleration, shock physics, and binary evolution. Despite major progress driven by…
The possible existence of additional long-period planetary-mass objects in the extrasolar planetary systems 47 UMa and 14 Her is investigated. We combine all available radial-velocity data on these stars, spanning up to 18 years. For the 47…
Preplanetary nebulae and planetary nebulae are evolved, mass-losing stellar objects that show a wide variety of morphologies. Many of these nebulae consist of outer structures that are nearly spherical (spiral/shell/arc/halo) and inner…