Related papers: V4334 Sgr (Sakurai's Nova): The Distance Problem
V605 Aquilae is today widely assumed to have been the result of a final helium shell flash occurring on a single post-asymptotic giant branch star. The fact that the outbursting star is in the middle of an old planetary nebula and that the…
We conducted a time-resolved photometric campaign of the helium dwarf nova, 2003aw in 2004 May--June. 2003aw stayed at 14.7--15.7 mag for the first several days during this campaign, which is the plateau phase of this superoutburst. This…
We present an empirical method which measures the distance to a Type Ia supernova (SN Ia) with a precision of ~ 10% from a single night's data. This method measures the supernova's age and luminosity/light-curve parameter from a spectrum,…
We have carried out a new photometric V,Rc study of 12 protoplanetary nebulae, objects in the short-lived transition between the AGB and PN phases of stellar evolution. These had been the subjects of an earlier study, using data from…
We report on photometric observations of V 1493 Aql during the early decline and highlight some uncommon aspects of the light curve. V 1493 Aql was hotter at maximum light than in the following phases, and was characterized by the presence…
We report the results of recent multicolor photometry and medium resolution spectroscopy of V838 Mon taken in 2007-2008. In the eclipse-like event in December 2006, the hot B3V type companion disappeared. The event accompanied by…
The impact of nova eruptions on the long-term evolution of Cataclysmic Variables(CVs) is one of the least understood and intensively discussed topics in the field. Acrucial ingredient to improve with this would be to establish a large…
Long-duration gamma-ray bursts (GRBs) and Type Ib/c Supernovae (SNe Ib/c) are amongst nature's most magnificent explosions. While GRBs launch relativistic jets, SNe Ib/c are core-collapse explosions whose progenitors have been stripped of…
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 analyse long-term optical photometry for two Galactic recurrent novae (V745 Sco and V3890 Sgr) and one Large Magellanic Cloud object (Nova LMC 1990b) observed over several years by the Optical Gravitational Lensing Experiment (OGLE) sky…
A classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in gamma rays and stood in…
The variable star DZ Cru was thought to be a nova when it was discovered in eruption in 2003 August. This explanation was later challenged, however, when the first spectra of the object were reported. We present near infrared spectroscopy…
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…
Type Ia supernovae (SNe Ia) are powerful cosmological "standardizable candles" and the most precise distance indicators. However, a limiting factor in their use for precision cosmology rests on our ability to correct for the dust extinction…
We present a $z = 0.94$ quasar, SDSS J004846.45-004611.9, discovered in the SDSS-III BOSS survey. A visual analysis of this spectrum reveals highly broadened and blueshifted narrow emission lines, in particular [Ne~V]$\lambda3426$ and…
We report serendipitous discovery of three new dwarf novae which eruptions in 2010 were observed by the ongoing microlensing survey OGLE-IV. All three objects are located in the Galactic bulge fields observed with the highest cadence of 20…
An eruptive nova-like event took place in 1994 in the stellar-merger candidate V4332 Sgr. Following the eruption, dust consisting of refractory silicate rich dust grains containing a significant component of AlO bonding was formed sometime…
Context. The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss rate/geometry and therefore knowing the geometry of the circumstellar material close to the star and its surroundings is…
We report observations of Type Ia SN 2021hem, located in an apparently hostless environment. With a peak absolute B-band magnitude of -19.96 mag, and a lack of secondary maximum in near-infrared and i-band light curves make it resemble…
The detection of supernova features in the late spectra of several gamma-ray burst afterglows has shown that at least a fraction of long-duration gamma-ray bursts are associated to the final evolutionary stages of massive stars. Such direct…