An Extremely Massive White Dwarf of the Symbiotic Classical Nova V407 Cyg as Suggested by the RS Oph and U SCO Models

AbstractWe have analyzed the optical light curve of the symbiotic star V407 Cyg that underwent a classical nova outburst in 2010 March. Being guided by a supersoft X-ray phase observed during days 20-40 after the nova outburst, we are able to reproduce the light curve during a very early phase of the nova outburst. Our model consists of an outbursting white dwarf and an extended equatorial disk. An extremely massive white dwarf of 1.35-1.37 M

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Photometric Evidence for the Presence of An Accretion Disk and for a Superhump - Like Phenomenon in the Classical Nova V1974 Cygni 1992

International Astronomical Union Colloquium ◽

10.1017/s0252921100044006 ◽

1997 ◽

Vol 163 ◽

pp. 788-789

Author(s):

A. Retter ◽

E.M. Leibowitz ◽

E.O. Ofek

Keyword(s):

Binary System ◽

Light Curve ◽

Accretion Disk ◽

Orbital Period ◽

White Dwarf ◽

Disk Model ◽

Classical Nova ◽

Nova Outburst

AbstractThe light curve of V1974 Cyg shows two distinct periodicities. The shorter periodicity is clearly the orbital period of the binary system. We show that the longer variation has similar features to permanent superhumps. This result indicates the existence of an accretion disk in the system no later than 30 months after the nova outburst. We used the precessing disk model of the superhump phenomenon and previous results in order to estimate that the white dwarf mass is at the range 0.75 – 1.07 M⊙.

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Optical Light Curve of Nova KT Eridani

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312019564 ◽

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.

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The X-Ray Evolution of the Symbiotic Star V407 Cyg During its 2010 Outburst

Open Astronomy ◽

10.1515/astro-2017-0358 ◽

2012 ◽

Vol 21 (1-2) ◽

Author(s):

K. Mukai ◽

T. Nelson ◽

L. Chomiuk ◽

D. Donato ◽

J. Sokoloski

Keyword(s):

Mass Loss ◽

Blast Wave ◽

White Dwarf ◽

Loss Rate ◽

Mass Loss Rate ◽

Symbiotic Star ◽

X Ray ◽

Binary Separation ◽

Nova Outburst

AbstractWe present a summary of Swift and Suzaku X-ray observations of the 2010 nova outburst of the symbiotic star, V407 Cyg. the Suzaku spectrum obtained on day 30 indicates the presence of the supersoft component from the white dwarf surface, as well as optically thin component from the shock between the nova ejecta and the Mira wind. the Swift observations then allow us to track the evolution of both components from day 4 to day 150. Most notable is the sudden brightening of the optically thin component around day 20. We identify this as the time when the blast wave reached the immediate vicinity of the photosphere of the Mira. We have developed a simpe model of the blast wave - wind interaction that can reproduce the gross features of the X-ray evolution of V407 Cyg. If the model is correct, the binary separation is likely to be larger than previously suggested and the mass-loss rate of the Mira is likely to be relatively low.

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The Optical Light Curve of LMC X-4 and the 30-Day X-Ray Period

X-Ray Astronomy ◽

10.1007/978-94-010-9949-3_61 ◽

1981 ◽

pp. 405-406

Author(s):

C. Chevalier ◽

S. A. Ilovaisky ◽

C. Motch ◽

M. Pakull ◽

J. Lub ◽

...

Keyword(s):

Light Curve ◽

X Ray ◽

Optical Light Curve

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Classical Novae – Before and After Outburst

International Astronomical Union Colloquium ◽

10.1017/s0252921100093908 ◽

1988 ◽

Vol 108 ◽

pp. 226-231

Author(s):

Mario Livio

Keyword(s):

White Dwarf ◽

Main Sequence ◽

Orbital Parameters ◽

Classical Novae ◽

Classical Nova ◽

Before And After ◽

Low Mass ◽

Orbital Periods ◽

Thermonuclear Runaway ◽

Nova Outburst

Classical nova (CN) and dwarf nova (DN) systems have the same binary components (a low-mass main sequence star and a white dwarf) and the same orbital periods. An important question that therefore arises is: are these systems really different ? (and if so, what is the fundamental difference ?) or, are these the same systems, metamorphosing from one class to the other ?The first thing to note in this respect is that the white dwarfs in DN systems are believed to accrete continuously (both at quiescence and during eruptions). At the same time, both analytic (e.g. Fujimoto 1982) and numerical calculations show, that when sufficient mass accumulates on the white dwarf, a thermonuclear runaway (TNR) is obtained and a nova outburst ensues (see e.g. reviews by Gallagher and Starrfield 1978, Truran 1982). It is thus only natural, to ask the question, is the fact that we have not seen a DN undergo a CN outburst (in about 50 years of almost complete coverage) consistent with observations of DN systems ? In an attempt to answer this question, we have calculated the probability for a nova outburst not to occur (in 50 years) in 86 DN systems (for which at least some of the orbital parameters are known).

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The optical light curve of LMC X-4 and the 30-day X-ray period

Space Science Reviews ◽

10.1007/bf01246055 ◽

1981 ◽

Vol 30 (1-4) ◽

pp. 405-406 ◽

Cited By ~ 6

Author(s):

C. Chevalier ◽

S. A. Ilovaisky ◽

C. Motch ◽

M. Pakull ◽

J. Lub ◽

...

Keyword(s):

Light Curve ◽

X Ray ◽

Optical Light Curve

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

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psaa071 ◽

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.

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Optical, X-ray, and γ-ray observations of the candidate transitional millisecond pulsar 4FGL J0427.8-6704

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa912 ◽

2020 ◽

Vol 494 (3) ◽

pp. 3912-3926

Author(s):

M R Kennedy ◽

R P Breton ◽

C J Clark ◽

V S Dhillon ◽

M Kerr ◽

...

Keyword(s):

Light Curve ◽

Time Scales ◽

Periodic Oscillation ◽

Optical Data ◽

Data Sets ◽

Millisecond Pulsar ◽

X Ray ◽

State Classification ◽

Optical Light Curve ◽

Γ Ray

ABSTRACT We present an optical, X-ray, and γ-ray study of 1SXPS J042749.2-670434, an eclipsing X-ray binary that has an associated γ-ray counterpart, 4FGL J0427.8-6704. This association has led to the source being classified as a transitional millisecond pulsar (tMSP) in an accreting state. We analyse 10.5 yr of Fermi LAT data and detect a γ-ray eclipse at the same phase as optical and X-ray eclipses at the >5 σ level, a significant improvement on the 2.8 σ level of the previous detection. The confirmation of this eclipse solidifies the association between the X-ray source and the γ-ray source, strengthening the tMSP classification. However, analysis of several optical data sets and an X-ray observation do not reveal a change in the source’s median brightness over long time-scales or a bi-modality on short time-scales. Instead, the light curve is dominated by flickering, which has a correlation time of 2.6 min alongside a potential quasi-periodic oscillation at ∼21 min. The mass of the primary and secondary stars is constrained to be $M_1=1.43^{+0.33}_{-0.19}$ M⊙ and $M_2=0.3^{+0.17}_{-0.12}$ M⊙ through modelling of the optical light curve. While this is still consistent with a white dwarf primary, we favour the tMSP in a low accretion state classification due to the significance of the γ-ray eclipse detection.

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