Imaging ejecta from the final flash star V605 Aquilae

Hinkle, Kenneth H.; Lebzelter, T.; Joyce, R. R.; Ridgway, S. T.; Close, Laird M.; Hron, J.; Andre, Karin

doi:10.1051/0004-6361:20077738

Cited by 24 publications

(25 citation statements)

References 82 publications

(134 reference statements)

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“…The mean value of MJD 0 corresponds to 1998 January 7, but the uncertainty allows the onset of the mass ejection that led to dust formation to have occurred between MJD 50745 (1997 November 24) and MJD 50895 (1998 March 23). This is close to the time at which the expansion of the dust shell started, on MJD 0 = 50762 (Evans et al 2006;Hinkle et al 2008).…”

Section: The Dust Masssupporting

confidence: 63%

“…They found that the expansion was linear in time, with an extrapolated start on 1997 November 10 (MJD 1 50762); the expansion rate was 0.059 mas d −1 . Hinkle et al (2008) determined a similar expansion rate (0.055 ± 0.008 mas d −1 ) over a somewhat longer time-base, also with a start in 1997 November. In either case the extrapolation to zero diameter coincided with the start of dust production sometime between 1997 Nov 7 (MJD 50759) and 1998 February 5 (MJD 50849;Dürbeck 2002).…”

Section: The Start Of the Dust Phasesupporting

confidence: 55%

See 1 more Smart Citation

The infrared view of dust and molecules around V4334 Sgr (Sakurai’s object): a 20-yr retrospective

Evans

Gehrz

Woodward

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present an analysis of the evolution of circumstellar dust and molecules in the environment of the very late thermal pulse object V4334 Sgr (Sakurai’s object) over an ∼20-yr period, drawing on ground-, airborne-, and space-based infrared photometry and spectroscopy. The dust emission, which started in 1997, resembles a blackbody that cooled from ∼1200 K in 1998 August to ∼180 K in 2016 July. The dust mass, assuming amorphous carbon, was ∼5 × 10−10 M⊙ in 1998 August, and we estimate that the total dust mass was ∼2 × 10−5 M⊙ by ∼2016. The appearance of a near-infrared excess in 2008 suggests that a new episode of (or renewed) mass-loss began then. We infer lower limits on the bolometric luminosity of the embedded star from that of the dust shell, which rose to ∼16 000 L⊙ before declining to ∼3000 L⊙. There is evidence for weak 6–7 μm absorption, which we attribute to hydrogenated amorphous carbon formed in material ejected by Sakurai’s object during a mass ejection phase that preceded the 1997 event. We detect small hydrocarbon and other molecules in the spectra, and trace the column densities in hydrogen cyanide (HCN) and acetylene (C2H2). We use the former to determine the 12C/13C ratio to be 6.4 ± 0.7, 14 times smaller than the Solar system value.

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Section: The Dust Masssupporting

confidence: 63%

Section: The Start Of the Dust Phasesupporting

confidence: 55%

The infrared view of dust and molecules around V4334 Sgr (Sakurai’s object): a 20-yr retrospective

Evans

Gehrz

Woodward

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Such an alignment between the disk and PN may not be fortuitous. In the case of V605 Aql, the disk and the planetary nebula A58 share the same major axis (Hinkle et al 2008). Of importance too is the low level of asymmetry detected in the old PN compared to that observed in the disk.…”

Section: Resultsmentioning

confidence: 89%

“…Only the event experienced by V605 Aql Reduced visibilities and differential phases are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/493/L17 can be considered as directly comparable (Clayton et al 2006;Clayton & De Marco 1997). V605 Aql underwent a final flash in 1917 and appears today to be still embedded in a disk-like dust structure (Clayton et al 2006;Hinkle et al 2008). …”

Section: Introductionmentioning

confidence: 99%

A dense disk of dust around the born-again Sakurai's object

Chesneau¹,

Clayton

Lykou

et al. 2008

A&A

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Context. In 1996, Sakurai's object (V4334 Sgr) suddenly brightened in the center of a faint Planetary Nebula (PN). This very rare event was interpreted as being the reignition of a hot white dwarf that caused a rapid evolution back to the cool giant phase. From 1998 on, a copious amount of dust has formed continuously, screening out the star that remained embedded in this expanding high opticaldepth envelope. Aims. We present observations that we use to study the morphology of the circumstellar dust to investigate the hypothesis that Sakurai's Object is surrounded by a thick spherical envelope of dust. Methods. We acquired unprecedented, high angular-resolution, spectro-interferometric observations, with the mid-IR interferometer MIDI/VLTI, which resolved the dust envelope of Sakurai's object. Results. We report the discovery of a unexpectedly compact (30 × 40 milliarcsec, 105 × 140 AU assuming a distance of 3.5 kpc), highly inclined, dust disk. We used Monte Carlo radiative-transfer simulations of a stratified disk to constrain its geometric and physical parameters, although such a model is only a rough approximation of the rapidly evolving dust structure. Even though the fits are not fully satisfactory, some useful and robust constraints can be inferred. The disk inclination is estimated to be 75• ± 3• with a large scale height of 47 ± 7 AU. The dust mass of the disk is estimated to be 6 × 10 −5 M . The major axis of the disk (132 • ± 3 • ) is aligned with an asymmetry seen in the old PN which was re-investigated as part of this study. This implies that the mechanism responsible for shaping the dust envelope surrounding Sakurai's object was already at work when the old PN formed.

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“…The mass loss associated with the final flash planetary nebula stage has been proposed to explain the shape and composition of exotic multi-shell planetary nebulae. Hinkle et al (2008) undertook a detailed investigation of the 80 + year old final flash object V605 Aql. The cloud of ejecta was imaged at high spatial resolution in both optical emission lines and infrared continuum.…”

mentioning

confidence: 99%

SpS1-Infrared spectroscopy of post-AGB objects

2009

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Post-AGB (pAGB) objects are low to intermediate initial mass ( 8 M ) objects that have terminated normal nuclear burning and as a result are undergoing rapid evolution toward the white dwarf sequence. In classical pAGB objects evolution is to hotter effective temperatures at roughly constant luminosity. However, there are also several classes of pAGB objects that have revived nuclear burning after approaching or being on the white dwarf sequence. These include objects with delayed final helium shell flashes (e.g. Sakurai's star) and white dwarf mergers (e.g. R CrB stars). Binary evolution plays a critical role in many of these systems. A group of pAGB supergiants with large infrared excesses are suspected to be binaries that have undergone common envelope evolution. Further details on many of these objects can be found in reviews, see for instance Van Winckel (2003) and Herwig (2005).The use of infrared (IR) tools has greatly increased our understanding of pAGB evolution. The strong infrared excess of these objects makes them very bright in the infrared and easily detectable in the mid-infrared. Many objects become embedded in their AGB mass loss and are optically obscured. The reduction of the obscuration and the brightness of pAGB objects in the IR makes them ideal targets for detailed analysis using IR spectroscopy. We report on three specific groups of pAGB objects.Post-common envelope binaries: Van Winckel et al. (1995) identified a class of pAGB singlelined, long-period, spectroscopic binaries. The primary star of these binaries is an early-type supergiant with very peculiar abundances. These objects typically have strong IR excesses, carbon-rich circumstellar dust, and a photospheric abundance pattern characterized by a severe deficiency of refractory elements and a near-solar abundance for volatile elements. The orbits of these objects suggest previous common envelope evolution when the primary was at the tip of the AGB. A circumbinary Keplerian rotating disk appears a common feature of these pAGB binaries (De Ruyter et al. 2006). Hinkle et al. (2007) report on high-resolution infrared spectroscopy in the 2.3-4.6 μm region. In the prototype HR 4049 the 4.6 μm spectrum shows a rich forest of CO and H2 O emission lines. All the spectral lines observed in the 2.3-4.6 μm spectrum are circumbinary in origin and originate in oxygen rich gas in contrast to the extended circumstellar carbon-rich gas. The emission and absorption line profiles show that the circumbinary gas is located in a thin, rotating layer near the dust disk. The velocities of the disk and the spectroscopic orbit yield masses for the individual stars, for HR 4049 MA I ∼0.58 M and MM V ∼0.34 M . Chemical processing in the disk is the likely method for producing the chemical peculiarities seen on the stellar photosphere.Final flash objects: Final helium shell flash evolution occurs in stars that have terminated their AGB stage and are either on the constant luminosity pAGB track or just entering the early white dwarf sequence. A final helium bu...

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Imaging ejecta from the final flash star V605 Aquilae

Cited by 24 publications

References 82 publications

The infrared view of dust and molecules around V4334 Sgr (Sakurai’s object): a 20-yr retrospective

The infrared view of dust and molecules around V4334 Sgr (Sakurai’s object): a 20-yr retrospective

A dense disk of dust around the born-again Sakurai's object

SpS1-Infrared spectroscopy of post-AGB objects

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