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The 30-year recurrent symbiotic nova V3890 Sgr exploded 2019 August 28 and was observed with multiple X-ray telescopes. An XMM-Newton observation during the SSS phase captured a high degree of X-ray variability including a deep dip in the…
A classical nova is an eruption on the surface of a white dwarf in an accreting binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell. The shaping mechanisms of nova shells are probes of the…
Classical novae are eruptions on the surface of a white dwarf in a binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell of gas and dust around the system. The three-dimensional structure of…
We present observations of the unusual optical transient SN 2010U, including spectra taken 1.03 days to 15.3 days after maximum light that identify it as a fast and luminous Fe II type nova. Our multi-band light curve traces the fast…
The recurrent nova (RN) V3890 Sgr was observed during the 7th day after the onset of its most recent outburst, with the Chandra ACIS-S camera and High Energy Transmission Gratings (HETG). A rich emission line spectrum was detected, due to…
I report the discovery of a new bright variable star in the constellation Scorpius. It is most likely star OGLE BUL-SC23 396060 with position (J2000.0): RA 17:57:59.75, DEC -31:38:07.4. Magnitude range is 14.4 (B) - 21.7 (V). It is visible…
We present early spectral observations of the very slow Galactic nova Gaia22alz, over its gradual rise to peak brightness that lasted 180 days. During the first 50 days, when the nova was only 3--4 magnitudes above its normal brightness,…
We report on the analysis of an X-ray grating spectrum of the Classical Nova V382 Vel (1999), obtained with the LETG+HRC-S instrument on board CHANDRA, which shows emission lines dominating over any continuum. Lines of Si, Mg, Ne, O, N, and…
Eruptions of classical novae are possible sources of lithium formation and gamma-ray emission. Nova remnants can also become Type Ia supernovae (SNe Ia). The contribution of novae to these phenomena depends on nova rates, which are not well…
L and M band observations of the nova-like variable V4332 Sgr are presented. Two significant results are obtained viz. the unusual detection of water ice at 3.05 microns and the fundamental band of 12CO at 4.67 microns in emission. The ice…
The classical nova V5583 Sgr (Nova Sagittarii 2009 No 3) has been observed during the rise phase and shortly after by NASA's STEREO/HI instruments, with later optical spectroscopy obtained with the R-C Spectrograph at CTIO, Chile. The time…
We present optical observations of the enigmatic nova-like variable V4332 Sgr. The importance of this object should not be understated since it is considered to be the possible prototype of a new class of eruptive variables. These objects…
V4332 Sgr is a red transient (red nova) whose eruption was observed in 1994. The remnant of the eruption shows a unique optical spectrum: strong emission lines of atoms and molecules superimposed on an M-type stellar spectrum. The…
Nova Her 2021 (V1674 Her), which erupted on 2021 June 12, reached naked-eye brightness and has been detected from radio to $\gamma$-rays. An extremely fast optical decline of 2 magnitudes in 1.2 days and strong Ne lines imply a high-mass…
We report optical photometry and optical through mid-infrared spectroscopy of the classical nova V1186 Sco. This slowly developing nova had an complex light curve with multiple secondary peaks similar to those seen in PW Vul. The time to…
We report results of optical imaging and low-resolution spectroscopic monitoring of supernova (SN) 2017iro that occurred in the nearby ($\sim$\,31 Mpc) galaxy NGC 5480. The \ion{He}{1} 5876 \AA\, feature present in the earliest spectrum…
V618 Sgr was previously classified as an R CrB-type variable and later as a possible symbiotic star. Our study aims to analyse the nature of this target, which is currently undergoing significant brightening in properties similar to those…
We report on X-ray observations of Nova Sagittarius 1998 (V4633 Sgr), performed with XMM-Newton at three different epochs, 934, 1083 and 1265 days after discovery. The nova was detected with the EPIC cameras at all three epochs, with…
Currently, it may take days for a bright nova outburst to be detected. With the few exceptions, little is known about novae behaviour prior to maximum light. A theoretically-predicted population of ultra-fast novae with t2<1d is evading…
We report photometry and spectroscopy of the evolution of Nova Sagittarii 1994 #1 (V4332 Sagittarii) during outburst. We compare the photometric and spectral evolution of this outburst to known classes of outbursts -- including classical…