Related papers: V4332 Sgr in 'Quiescence'

We show that Supernova (SN) 2002kg in NGC 2403, initially classified as Type II-narrow (IIn), has photometric and spectroscopic properties unlike those of normal SNe. Its behavior, instead, is more typical of highly massive stars which…

V838 Mon has undergone one of the most mysterious stellar outbursts on record, with (a) a large amplitude (Delta B ~ 10 mag) and multi-maxima photometric pattern, (b) a cool spectral type at maximum becoming cooler and cooler with time…

We present observations of M31LRN 2015 (MASTER OT J004207.99+405501.1), discovered in M31 in 2015 January, and identified as a rare and enigmatic luminous red nova (LRN). Spectroscopic and photometric observations obtained by the Liverpool…

We report spectra of the overtone and fundamental bands of CO in the eruptive variable V838 Mon, which trace the recent evolution of the star and allow its ejecta to be characterized. The data were obtained at the United Kingdom Infrared…

NSV 10934 was discovered as a large-amplitude suspected variable star of unknown classification. We noticed that the object is identified with a bright ROSAT X-ray source (1RXS J184050.3-834305). Systematic monitoring of this object by the…

Nova Sco 2008 (=V1309 Sco) is an example of a V838 Mon type eruption rather than a typical classical nova. This enigmatic object was recently shown to have resulted from the merger of two stars in a contact binary. It is the first stellar…

The black hole candidate V4641 Sgr (= SAX J1819.3-2525) went through a brief outburst during 2003 Aug 01 to Aug 08. During the outburst, activity was noted in optical, radio as well as X-rays. Here we present results of Spectral and…

The 18 mag QSO 1633+382 (4C38.41, z=1.807) showed a very pronounced outburst in 2001/2002. With a peak amplitude of more than 9 Jy at 90GHz, this flare was brighter than any known previous flare in this source (data available since…

We present imaging polarimetry observations of the eruptive variable V838 Monocerotis and its neighboring field obtained in 2002 October. The polarization of field stars confirms the previously determined interstellar polarization along the…

We report the XMM-Newton/EPIC detection in 2008 March of a luminous (L_X ~ 10^32-33 erg/s), variable X-ray source in the vicinity (within ~6") of the enigmatic star V838 Mon, which underwent a spectacular outburst in early 2002. Spectral…

The central star V4334 Sgr (Sakurai's Nova) of the planetary nebula PN G010.4+04.4 underwent in 1995-1996 the rare event of a very late helium flash. It represents only one out of two such events during the era of modern astronomy (the…

Context: In late November 2013 a fifth eruption in five years of the M31 recurrent nova M31N 2008-12a was announced. Aims: In this Letter we address the optical lightcurve and progenitor system of M31N 2008-12a. Methods: Optical imaging…

The Luminous Blue Variable (LBV) R71 is currently undergoing an eruption, which differs photometrically and spectroscopically from its last outburst in the 1970s. Valuable information on the physics of LBV eruptions can be gained by…

We present progenitor-star detections, light curves, and optical spectra of SN2009ip and the 2009 optical transient in UGC2773 (U2773-OT), which were not genuine SNe. Precursor variability in the decade before outburst indicates that both…

We report the discovery of multiple shells around the eruptive variable star V838 Mon. Two dust shells are seen in IRAS and MSX images, which themselves are situated in a shell of CO. This securely establishes V838 Mon as an evolved object.…

We analyse photometric observations of the supernova (SN) impostor SN 2000ch in NGC 3432 covering the time since its discovery. This source was previously observed to have four outbursts in 2000-2010. Observations now reveal at least three…

The aim of this paper is to look at the evolution of massive stars in order to determine whether or not the progenitor of V838 Mon may be a massive star. In the first part of this paper, the evolution of massive stars around solar…

X-ray transients provide unique opportunity to probe accretion regimes of at a vastly different accretion rates. We analyze a collection of the RXTE observations (Galactic Center scans, ASM monitoring and a pointed observation) of enigmatic…

Some classes of stars, including supernovae and novae, undergo explosive outbursts that eject stellar material into space. In 2002, the previously unknown variable star V838 Monocerotis brightened suddenly by a factor of about 10^4. Unlike…

We summarize and analyze the available observational data on the progenitor and the enviroment of V838 Mon. From the available photometric data for the progenitor of V838 Mon we exclude the possibility that the object before eruption was an…