A Universal Decline Law of Classical Novae. Iv. V838 Her (1991): A Very Massive White Dwarf

Kato, Mariko; Hachisu, Izumi; Cassatella, A.

doi:10.1088/0004-637x/704/2/1676

Cited by 29 publications

(43 citation statements)

References 59 publications

(117 reference statements)

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“…We adopt the optically thick winds (e.g., Kato 1983Kato , 1985Kato & Hachisu 1994) as the main mechanism of mass-loss during the nova outburst. The optically thick winds have been applied to a number of novae and have successfully reproduced light curves and characteristic properties (e.g., Hachisu & Kato 2006, 2007Hachisu et al 2008;Kato et al 2009;. The interior structures of WDs are calculated with a Henyey code (Section 2.1).…”

Section: Methodsmentioning

confidence: 99%

A Self-consistent Model for a Full Cycle of Recurrent Novae—Wind Mass-loss Rate and X-Ray Luminosity

Kato

Saio

Hachisu

2017

ApJ

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An unexpectedly slow evolution in the pre-optical-maximum phase was suggested in the very short recurrence period of nova M31N 2008-12a. To obtain reasonable nova light curves we have improved our calculation method by consistently combining optically thick wind solutions of hydrogen-rich envelopes with white dwarf (WD) structures calculated by a Henyey-type evolution code. The wind mass-loss rate is properly determined with high accuracy. We have calculated light curve models for 1.2M e and 1.38 M e WDs with mass accretion rates corresponding to recurrence periods of 10 yr and 1 yr, respectively. The outburst lasts 590/29 days, in which the pre-optical-maximum phase is 82/16 days, for 1.2/1.38 M e , respectively. Optically thick winds start at the end of the X-ray flash and cease at the beginning of the supersoft X-ray phase. We also present supersoft X-ray light curves including a prompt X-ray flash and later supersoft X-ray phase.

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Section: Methodsmentioning

confidence: 99%

A Self-consistent Model for a Full Cycle of Recurrent Novae—Wind Mass-loss Rate and X-Ray Luminosity

Kato

Saio

Hachisu

2017

ApJ

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“…This presumption is based largely on theoretical models, and backed up by only a limited number of observations of some RN WD masses, but we are confident that the presumption is robust. I. Hachisu and M. Kato have a series of papers (Hachisu & Kato 2004, 2006Hachisu et al 2008aHachisu et al , 2008bKato & Hachisu 2003bKato et al 2009;Kato & Hachisu 2011) wherein they model 34 CN light curves and derive M WD . Of the systems listed in Table 3, 7 of 27 have M WD 1.2 M , for a fraction of 25.9%, and two newer systems have M WD 1.2 M as well.…”

Section: White Dwarf Massmentioning

confidence: 99%

Identifying and Quantifying Recurrent Novae Masquerading as Classical Novae

Pagnotta

Schaefer

2014

ApJ

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Recurrent novae (RNe) are cataclysmic variables with two or more nova eruptions within a century. Classical novae (CNe) are similar systems with only one such eruption. Many of the so-called CNe are actually RNe for which only one eruption has been discovered. Since RNe are candidate Type Ia supernova progenitors, it is important to know whether there are enough in our Galaxy to provide the supernova rate, and therefore to know how many RNe are masquerading as CNe. To quantify this, we collected all available information on the light curves and spectra of a Galactic, time-limited sample of 237 CNe and the 10 known RNe, as well as exhaustive discovery efficiency records. We recognize RNe as having (1) outburst amplitude smaller than 14.5 − 4.5 × log(t 3 ), (2) orbital period >0.6 days, (3) infrared colors of J − H > 0.7 mag and H − K > 0.1 mag, (4) FWHM of Hα > 2000 km s −1 , (5) high excitation lines, such as Fe x or He ii near peak, (6) eruption light curves with a plateau, and (7) white dwarf mass greater than 1.2 M . Using these criteria, we identify V1721 Aql, DE Cir, CP Cru, KT Eri, V838 Her, V2672 Oph, V4160 Sgr, V4643 Sgr, V4739 Sgr, and V477 Sct as strong RN candidates. We evaluate the RN fraction among the known CNe using three methods to get 24% ± 4%, 12% ± 3%, and 35% ± 3%. With roughly a quarter of the 394 known Galactic novae actually being RNe, there should be approximately a hundred such systems masquerading as CNe. Key word: novae, cataclysmic variablesOnline-only material: color figures, machine-readable table 1. RECURRENT NOVA CANDIDATES Both classical and recurrent novae (CNe and RNe, respectively) consist of a white dwarf (WD) accreting material from a companion star. The accreted material accumulates until reaching a critical temperature/pressure at the base of the accreted layer, at which point thermonuclear runaway is triggered and the nova eruption occurs. The outburst mechanism is identical for both CNe and RNe, but the recurrence timescale varies by multiple orders of magnitude, with RNe seen to erupt at least once per century. The systems classified as CNe have only one discovered eruption, but more undiscovered eruptions could have occurred within the last century. The truly classical systems do not have any more eruptions on timescales of less than a century. We note that this century-long timescale is empirically based on observations, and is somewhat arbitrary, arising due more to the history of reliably recorded, large-scale observations (dating back to the 1890s, when the first astronomical plates were made) than to any physical distinction. We anticipate needing to either expand the definition of an RN in the future, as we discover systems with recurrence times just slightly greater than 100 yr, or to alter the nomenclature to something such as Fast Recurrence Time Novae, to distinguish systems whose recurrences we have had time to observe from those for which we still wait, a wait time which may be on the order of 10 5 yr. For this paper, we will continue with the curr...

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“…The spectral resolution was λ/Δλ 800 with a grating of 600 lines mm −1 , and the spectrophotometric calibrations were made using the spectra of the standard star Kopff 27 obtained in the same nights. The interstellar extinction was corrected assuming E(B − V) = 0.53 (Kato et al 2009). A log of the observations is given in Table 1, where UT is the universal time at the start of exposure.…”

Section: Spectral Evolutionmentioning

confidence: 99%

“…Intensities of prominent emission lines relative to Hβ = 100 are measured in the spectra obtained on 1991 April 2, where the interstellar extinction is corrected by E(B − V) = 0.53 (Kato et al 2009). The results are given in Table 2.…”

Section: Helium Abundancementioning

confidence: 99%

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Spectral evolution of the extremely fast classical nova V838 Herculis

Iijima¹,

Cassatella

2010

A&A

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Spectral evolution of nova V838 Her 1991 was monitored at Asiago Astrophysical Observatory from 1991 March 31 to July 2. The spectra in the early decline stage showed emission lines of H I, He I, He II, N II, N III, C II, C III, C IV, Si II, [S III], [Ne III], and Fe II, where some identifications are different from those reported in the previous works. The emission lines of [Ne III] and carbon ions were unusually intense. New emission peaks appeared at the blue-ward edges of the emission lines of H I and He I about one week after maximum luminosity. It seems that a new clump of gas was ejected at that time along the line of sight towards us. The helium abundance is estimated at N(He) = 0.11 ± 0.01.

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A Universal Decline Law of Classical Novae. Iv. V838 Her (1991): A Very Massive White Dwarf

Cited by 29 publications

References 59 publications

A Self-consistent Model for a Full Cycle of Recurrent Novae—Wind Mass-loss Rate and X-Ray Luminosity

A Self-consistent Model for a Full Cycle of Recurrent Novae—Wind Mass-loss Rate and X-Ray Luminosity

Identifying and Quantifying Recurrent Novae Masquerading as Classical Novae

Spectral evolution of the extremely fast classical nova V838 Herculis

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