scholarly journals On the 2011 Outburst of the Recurrent Nova T Pyxidis

2015 ◽  
Vol 2 (1) ◽  
pp. 264-268
Author(s):  
L. Izzo ◽  
M. Della Valle ◽  
A. Ederoclite ◽  
M. Henze
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Line Profiles ◽  
X Ray ◽  
Recurrent Nova ◽  
System Configurations

We discuss the nebular phase emission during the 2011 outburst of the recurrent nova T Pyxidis and present preliminaryresults on the analysis of the line profiles. We also present some discussions about the binary system configurations and the X-ray emission, showing that the white dwarf mass should be larger than 0.8 M<sub>Θ</sub>.

scholarly journals Supersoft X-ray phases of recurrent novae as an indicator of their white dwarf masses

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Mariko Kato ◽  
Izumi Hachisu
Keyword(s):  
Light Curve ◽  
White Dwarf ◽  
Total Duration ◽  
Simple Relation ◽  
Light Curves ◽  
Curve Shape ◽  
Plateau Phase ◽  
Hydrogen Burning ◽  
X Ray ◽  
Recurrent Nova

Abstract We have examined the optical/X-ray light curves of seven well-observed recurrent novae, V745 Sco, M31N 2008-12a, LMC N 1968, U Sco, RS Oph, LMC N 2009a, T Pyx, and one recurrent nova candidate LMC N 2012a. Six novae out of the eight show a simple relation that the duration of supersoft X-ray source (SSS) phase is 0.70 times the total duration of the outburst (= X-ray turnoff time), i.e., tSSS = 0.70 toff, the total duration of which ranges from 10 to 260 d. These six recurrent novae show a broad rectangular X-ray light curve shape, the first half-period of which is highly variable in the X-ray count rate. The SSS phase also corresponds to an optical plateau phase that indicates a large accretion disk irradiated by a hydrogen-burning white dwarf (WD). The two other recurrent novae, T Pyx and V745 Sco, show a narrow triangular-shaped X-ray light curve without an optical plateau phase. Their relations between tSSS and toff are rather different from the above six recurrent novae. We also present theoretical SSS durations for recurrent novae with various WD masses and stellar metallicities (Z = 0.004, 0.01, 0.02, and 0.05) and compare them with the observed durations of these recurrent novae. We show that SSS duration is a good indicator of WD mass in recurrent novae with a broad rectangular X-ray light curve shape.

A comparison of optical and X-ray novae

1979 ◽  
Vol 366 (1726) ◽  
pp. 357-365
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Theoretical Models ◽  
Dwarf Novae ◽  
X Ray ◽  
Classical Novae ◽  
Binary Structure ◽  
Nuclear Burning ◽  
Similarities And Differences

The similarities and differences between optical novae and transient X-ray novae are discussed. Both classes almost certainly require a semi­-detached binary structure. Present theoretical models of classical novae account for the outburst in terms of a nuclear burning runaway in the accreted material on the white dwarf within a semi-detached binary system. In the case of the dwarf novae and the transient X-ray sources, unstable accretion events are the generally accepted model. Mechanisms that could generate unstable accretion events are described.

scholarly journals Multi-Frequency Observations of the 1985 Outburst of RS Ophiuchi

1987 ◽  
Vol 93 ◽  
pp. 243-254
Author(s):  
M.A.J. Snijders
Keyword(s):  
White Dwarf ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Recurrent Nova ◽  
Radio Frequencies

AbstractThe 1985 outburst of the bright, recurrent nova RS Oph was almost simultaneously observed at X-ray, UV, optical, IR and radio frequencies at many epochs. The abundances in the ejected shell and the development of the bolometric luminosity as a function of time suggest that the cause of the outburst is a nuclear runaway on a massive white dwarf.

scholarly journals Swift J011511.0-725611: discovery of a rare Be star/white dwarf binary system in the SMC

2021 ◽  
Vol 508 (1) ◽  
pp. 781-788
Author(s):  
J A Kennea ◽  
M J Coe ◽  
P A Evans ◽  
L J Townsend ◽  
Z A Campbell ◽  
...  
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
South African ◽  
White Dwarf ◽  
Compact Object ◽  
Type Ii ◽  
Large Telescope ◽  
X Ray ◽  
Be Star

ABSTRACT We report on the discovery of Swift J011511.0-725611, a rare Be X-ray binary system (BeXRB) with a white dwarf (WD) compact object, in the Small Magellanic Cloud (SMC) by S-CUBED, a weekly X-ray/UV survey of the SMC by the Neil Gehrels Swift Observatory. Observations show an approximately 3 month outburst from Swift J011511.0-725611, the first detected by S-CUBED since it began in 2016 June. Swift J011511.0-725611 shows supersoft X-ray emission, indicative of a WD compact object, which is further strengthened by the presence of an 0.871 keV edge, commonly attributed to O viii K-edge in the WD atmosphere. Spectroscopy by South African Large Telescope confirms the Be nature of the companion star, and long term light curve by OGLE finds both the signature of a circumstellar disc in the system at outburst time, and the presence of a 17.4 day periodicity, likely the orbital period of the system. Swift J011511.0-725611 is suggested to be undergoing a Type-II outburst, similar to the previously reported SMC Be white dwarf binary (BeWD), Swift J004427.3-734801. It is likely that the rarity of known BeWD is in part due to the difficulty in detecting such outbursts due to both their rarity, and their relative faintness compared to outbursts in Neutron Star BeXRBs.

scholarly journals New Photometric Observations of RS Oph

2011 ◽  
Vol 7 (S281) ◽  
pp. 201-202
Author(s):  
Irina Voloshina ◽  
Vladimir Metlov
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Astronomical Institute ◽  
Long Period ◽  
Photometric Observations ◽  
Sternberg Astronomical Institute ◽  
Recurrent Nova ◽  
Type Giant ◽  
Chandrasekhar Limit

AbstractThe recurrent nova RS Oph is a long period (~455 days) binary system consisting of a hot white dwarf with mass close to the Chandrasekhar limit and an M-type giant secondary. Here we present the results of photometric observations of this nova which were made during recent years with the telescopes of the Sternberg Astronomical Institute in Crimea.

scholarly journals Optical Frequencies in V471 TAU

1989 ◽  
Vol 114 ◽  
pp. 293-295
Author(s):  
D. E. Winget ◽  
C. F. Claver
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Mean Amplitude ◽  
Dwarf Star ◽  
Pulsed Light ◽  
Eclipsing Binary ◽  
X Ray ◽  
Significant Power ◽  
Hyades Cluster ◽  
S Period

V471 Tau is a spectroscopic and eclipsing binary system located in the Hyades cluster. The binary consists of a K2V and a hot DA white dwarf star (Nelson and Young 1970). Soft x-ray observations reveal strong modulation at periods of 554.7 ± 0.3s and 277.5 ± 0.1s (Jensen 1985, Jensnen et al. 1986).Robinson et al. (1988) reported the detection of the 555 s period in the optical. This period was about a factor of 20 reduced in mean amplitude in their data relative to the soft x-ray amplitude. They also found that it varied in amplitude from run to run by more than a factor of 2.5, dropping below detectability on several runs. They found some evidence for the 277.5 s period in several runs, but never at high enough amplitude to measure reliably. In addition, they noted that several of their runs had statistically significant power at other frequencies, but noted that in their six runs none of the additional frequencies repeated themselves. Robinson et al. also used observations near the eclipse of the white dwarf to demonstrate that most of the pulsed light is coming from the white dwarf.

scholarly journals THE 2011 OUTBURST OF RECURRENT NOVA T Pyx: X-RAY OBSERVATIONS EXPOSE THE WHITE DWARF MASS AND EJECTION DYNAMICS

2014 ◽  
Vol 788 (2) ◽  
pp. 130 ◽  
Author(s):  
Laura Chomiuk ◽  
Thomas Nelson ◽  
Koji Mukai ◽  
J. L. Sokoloski ◽  
Michael P. Rupen ◽  
...  
Keyword(s):  
White Dwarf ◽  
X Ray ◽  
Recurrent Nova

scholarly journals Optical Light Curve of Nova KT Eridani

2012 ◽  
Vol 8 (S290) ◽  
pp. 191-192
Author(s):  
W. P. Chen ◽  
L. W. Hung ◽  
Fred Walter
Keyword(s):  
Light Curve ◽  
White Dwarf ◽  
Hot Spot ◽  
X Ray ◽  
Optical Emissions ◽  
Optical Light Curve ◽  
Recurrent Nova ◽  
Orbital Modulation ◽  
Type Giant

AbstractWe present the optical light curve of the very fast nova, KT Eridani, from its outburst in November 2009 to quiescence in 2012. Comparison of our data with the 24-hour monitoring by Swift on 2010 March 31 indicates a possible anticorrelation between the X-ray and optical emissions. A period of 57 d is found in the long-term optical light curve, which we interpret as the orbital modulation of the hot spot on the white dwarf disk accreting material from an early K-type giant. Our study lends support to the notation that KT Eri may be a recurrent nova.

scholarly journals X-Ray Observations of Classical and Recurrent Novae in Outburst

2004 ◽  
Vol 194 ◽  
pp. 182-186 ◽  
Author(s):  
M. Orio
Keyword(s):  
Light Curve ◽  
White Dwarf ◽  
Circumstellar Matter ◽  
X Rays ◽  
Hydrogen Burning ◽  
X Ray ◽  
High Fraction ◽  
Emission Line Spectrum ◽  
Recurrent Nova ◽  
Red Giant

AbstractI review X-ray observations of classical and recurrent novae in outburst, some of them recently done with Chandra and XMM-Newton for 12 objects. Significant X-ray flux is emitted by the nova shell, with a peak luminosity up to Lx = 1035 erg s–1 in the 0.2-10 keV range. In recurrent nova systems, or in novae hosting a red giant, the source of X-rays may be previous circumstellar matter shocked by the nova wind. However, for most classical novae, X-rays originate inside the nebula ejected in the outburst. The data indicate a very high fraction of shocked material, and a non-smooth, varying wind outflow. A nebular emission line spectrum is also observed at late phases. In about half of the observed novae, the central white dwarf appears as a very luminous supersoft X-ray source for 1 to 9 years after the outburst. It is the best type of object to study the characteristics of shell hydrogen burning on white dwarfs in single degenerate systems. Still incomplete statistics indicate that the duration of the supersoft X-ray phase is peaked around ≃2 years. The correlation of the X-ray light curve with the nova properties is not quite clear. Recently, “template grating spectra” with high S/N have been obtained for V4743 Sgr. The X-ray light curve of this nova reveals a rich and complex power spectrum, with signatures of non-radial g-mode oscillations of the white dwarf. The oscillations and the spectra allow to determine the properties of the shell hydrogen burning white dwarf.

scholarly journals Hydrogen Depletion and the Evolution of Cataclysmic Variables to Low Mass X-Ray Binaries

1987 ◽  
Vol 93 ◽  
pp. 681-685
Author(s):  
R.E. Williams ◽  
M.M. Phillips ◽  
S.R. Heathcote
Keyword(s):  
Emission Line ◽  
White Dwarf ◽  
White Dwarfs ◽  
Cataclysmic Variables ◽  
Core Collapse ◽  
X Ray ◽  
Low Mass ◽  
Recurrent Nova ◽  
Chandrasekhar Limit ◽  
X Ray Binaries

AbstractCertain cataclysmic variables may evolve into low mass X-ray binaries if the white dwarfs can steadily accrete sufficient mass to exceed the Chandrasekhar limit. We present spectra of a recurrent nova and a low mass X-ray binary which are very similar to each other, and are also unusual for the strengths of the observed He II emission. We suggest that this similarity is not coincidental, but is evidence for an evolutionary link between the two classes of objects. A hydrogen depletion in the accreting gas is implied from the emission line fluxes, and may be an important parameter in determining whether accreted gas remains bound to the white dwarf, enabling eventual core collapse to occur.

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