Novae between outbursts

Livio, Mario

doi:10.1007/3-540-53500-4_146

Cited by 9 publications

(10 citation statements)

References 33 publications

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“…However, the hibernation theory of cyclic evolution between CV variability types , and references therein), predicts that when eventually M 0 decreases back into the instability regime some decades after the nova outburst, then dwarf nova outbursts should resume. Both GK Persei (\Nova Per 1901 ; Bianchini et al 1986) and V446 Herculis (\Nova Her 1960 ; Honeycutt et al 1998b) have displayed dwarf nova eruptions in their postnova stages, and similar behavior has been suggested for a number of other old novae, commencing B50È200 yr after their outbursts (Livio 1989 ;Warner 1995, chap. 4).…”

Section: Optical Photometric Variabilitymentioning

confidence: 73%

Long‐Term Optical and X‐Ray Observations of the Old Novae DI Lacertae and V841 Ophiuchi1

Hoard¹,

Szkody²,

Honeycutt³

et al. 2000

PUBL ASTRON SOC PAC

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ABSTRACT. We present an analysis of ground-based optical photometry and spectroscopy and Rossi X-Ray T iming Explorer X-ray observations of the old novae DI Lacertae and V841 Ophiuchi. Our optical photometry data (obtained with the automated photometry telescope RoboScope) comprise an almost decade-long light curve for each star, while the contemporaneous spectroscopy and X-ray observations repeatedly sampled each nova during separate intervals of B45È55 days in length. The long-term optical light curves of both novae reveal quasi-periodic variability on typical timescales of D30È50 days with amplitudes of *V D 0.4È0.8 mag. V841 Oph also displays a long-term, sinusoidal modulation of its optical light on a timescale of 3.5È5 yr. The optical spectra of these novae display quite di †erent characteristics from each other, with DI Lac showing narrow Balmer emission cores situated in broad absorption troughs while V841 Oph exhibits strong single-peaked Balmer, He I, and He II emission lines. We Ðnd little change between spectra obtained during di †erent optical brightness states. The X-ray count rates for both novae were very low counts s~1), and there was no reliable correlation between X-ray and optical brightness. The ([1.5 combined X-ray spectrum of DI Lac is best Ðt by a bremsstrahlung emission model (with kT D 4 keV and cm~3) ; the X-ray spectrum of V841 Oph is too weak to allow model Ðtting. We discuss the N H \ 1.8 ] 1022 possible origin of variability in these old novae in terms of magnetic activity on the secondary star, dwarf nova type disk instabilities, and the "" hibernation ÏÏ scenario for cataclysmic variable stars.

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Section: Optical Photometric Variabilitymentioning

confidence: 73%

Long‐Term Optical and X‐Ray Observations of the Old Novae DI Lacertae and V841 Ophiuchi1

Hoard¹,

Szkody²,

Honeycutt³

et al. 2000

PUBL ASTRON SOC PAC

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“…Dwarf nova outbursts a few decades before the nova eruption of V446 Her have probably been observed as well. Livio (1989) and Warner (1995a) listed a few other cases, however, the evidence for such a transition in these systems is rather poor. Robinson (1975) compared the magnitudes of 18 old novae with the values of their progenitors.…”

Section: Existing Nova Cycle Models For Cvsmentioning

confidence: 99%

“…The 'hibernation scenario' (Shara et al 1986;Prialnik & Shara 1986;Shara 1989) suggests that dwarf novae → nova-likes → novae → nova-likes → dwarf novae → 'hibernation' → dwarf novae etc. However, it was later proposed that the 'hibernation' phase ( Ṁ ≈0) might not exist at all (Livio 1989), thus dwarf novae → nova-likes → novae → ⋆ We exclude GK Per as it is a very atypical nova -its orbital period is very long (∼2 d), and its secondary star is believed to be a sub-giant (e.g. Dougherty et al 1996) unlike red dwarf companions in classical novae.…”

Section: Existing Nova Cycle Models For Cvsmentioning

confidence: 99%

Thermal stability and nova cycles in permanent superhump systems

Retter

Naylor

2000

Monthly Notices of the Royal Astronomical Society

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Archival data on permanent superhump systems are compiled to test the thermal stability of their accretion discs. We find that their discs are almost certainly thermally stable as expected. This result confirms Osaki's suggestion that permanent superhump systems form a new subclass of cataclysmic variables (CVs), with relatively short orbital periods and high mass-transfer rates. We note that if the high accretion rates estimated in permanent superhump systems represent their mean secular values, then their mass-transfer rates cannot be explained by gravitational radiation, therefore, either magnetic braking should be extrapolated to systems below the period gap or they must have mass-transfer cycles. Alternatively, a new mechanism that removes angular momentum from CVs below the gap should be invoked.We suggest applying the nova cycle scenarios offered for systems above the period gap to the short orbital period CVs. Permanent superhumps have been observed in the two nonmagnetic ex-novae with binary periods below the gap. Their post-nova magnitudes are brighter than their pre-outburst values. In one case (V1974 Cyg) it has been demonstrated that the pre-nova should have been a regular SU UMa system. Thus, it is the first nova whose accretion disc was observed to change its thermal stability. If the superhumps in this system indicate persistent high mass-transfer rates rather than a temporary change induced by irradiation from the hot post-nova white dwarf, it is the first direct evidence for mass-transfer cycles in CVs. The proposed cycles are driven by the nova eruption.

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“…Multiple physical mechanisms, including hydrodynamic pressure supported by heat from nuclear reactions (Sparks 1969;Starrfield et al 1978;Prialnik 1986), radiation pressure (Bath & Shaviv 1976;Sparks et al 1978;Kato & Hachisu 1994;Shaviv 2001), and interactions with a binary companion (MacDonald et al 1985;Livio 1990;Livio et al 1990), have long been recognized as potential causes of envelope ejection in novae. The 'slow torus -fast bipolar wind' scenario of nova eruption outlined by Livio (1990); Chomiuk et al (2014Chomiuk et al ( , 2021a; Mukai & Sokoloski (2019), and Shen & Quataert (2022) can be summarized as follows. Thermonuclear reactions heat the white dwarf atmosphere that expands engulfing the binary.…”

Section: Introductionmentioning

confidence: 99%

The multi-wavelength view of shocks in the fastest nova V1674 Her

Sokolovsky,

Johnson,

Buson

et al. 2023

Preprint

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Classical novae are shock-powered multi-wavelength transients triggered by a thermonuclear runaway on an accreting white dwarf. V1674 Her is the fastest nova ever recorded (time to declined by two magnitudes is 2 = 1.1 d) that challenges our understanding of shock formation in novae. We investigate the physical mechanisms behind nova emission from GeV -rays to cm-band radio using coordinated Fermi-LAT, NuSTAR, Swift and VLA observations supported by optical photometry. Fermi-LAT detected short-lived (18 h) 0.1-100 GeV emission from V1674 Her that appeared 6 h after the eruption began; this was at a level of (1.6 ± 0.4) × 10 −6 photons cm −2 s −1 . Eleven days later, simultaneous NuSTAR and Swift X-ray observations revealed optically thin thermal plasma shock-heated to k shock = 4 keV. The lack of a detectable 6.7 keV Fe K emission suggests supersolar CNO abundances. The radio emission from V1674 Her was consistent with thermal emission at early times and synchrotron at late times. The radio spectrum steeply rising with frequency may be a result of either free-free absorption of synchrotron and thermal emission by unshocked outer regions of the nova shell or the Razin-Tsytovich effect attenuating synchrotron emission in dense plasma. The development of the shock inside the ejecta is unaffected by the extraordinarily rapid evolution and the intermediate polar host of this nova.

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Novae between outbursts

Cited by 9 publications

References 33 publications

Long‐Term Optical and X‐Ray Observations of the Old Novae DI Lacertae and V841 Ophiuchi1

Long‐Term Optical and X‐Ray Observations of the Old Novae DI Lacertae and V841 Ophiuchi1

Thermal stability and nova cycles in permanent superhump systems

The multi-wavelength view of shocks in the fastest nova V1674 Her

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