Characteristics of dust shells around 13 late-type stars

Danchi, W. C.; Bester, M.; Degiacomi, C. G.; Greenhill, L. J.; Townes, C. H.

doi:10.1086/116960

Cited by 338 publications

(485 citation statements)

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“…This is of course very much an oversimplification, but it produces a good first-order fit to the near-infrared colours. The displacement of RR Tel, like that of other symbiotic Miras, with respect to the single Miras, is according to the present model, a consequence of the higher temperature (600-800 K) of the dust shell around the cool component (Danchi et al 1994), compared with temperatures 100-300 K of non-symbiotic Miras (Whitelock 1987). (2000) and with thick dust shells (full circles) from Whitelock et al (1994).…”

Section: Jhkl Colourssupporting

confidence: 67%

The effect of dust obscuration in RR Telescopii on optical and IR long-term photometry and Fe II emission lines

Kotnik-Karuza¹,

Friedjung²,

Whitelock³

et al. 2006

A&A

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Aims. Infrared and optical photometric and spectroscopic observations of the symbiotic nova RR Tel are used to study the effects and properties of dust in symbiotic binaries containing a cool Mira component, as well as showing "obscuration events" of increased absorption, which are typical for such Miras. Results. We discuss the three periods during which the Mira component was heavily obscured by dust as observed in the different wavelength bands. A change in the correlations of J with other infrared magnitudes was observed with the colour becoming redder after JD 2 446 600. Generally, J−K was comparable, while K −L was larger than typical values for single Miras. A distance estimate of 2.5 kpc, based on the IR data, is given. A larger flux decrease for the permitted than for the forbidden Fe II lines, during the obscuration episode studied, has been found. There is no evidence for other correlations with line properties, in particular with wavelength, which suggests obscuration due to separate optically thick clouds in the outer layers. Conclusions.

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Section: Jhkl Colourssupporting

confidence: 67%

The effect of dust obscuration in RR Telescopii on optical and IR long-term photometry and Fe II emission lines

Kotnik-Karuza¹,

Friedjung²,

Whitelock³

et al. 2006

A&A

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“…Multiwavelength angular diameter measurements of Mira (Hani †, Scholz, & Tuthill 1995) Danchi et al (1994) and Hani † et al (1995). They arrive at similar temperatures : a mean (over phases) e †ective temperature of about K. We note, however, that T eff B 2800 this value is low as compared with the values suggested by Perrin et al (1998) for giants in the interval M4 IIIÈM7 III which is characteristic of Miras.…”

Section: Mirasupporting

confidence: 57%

Mira’s Wind Explored in Scattering Infrared CO Lines

Ryde¹,

Gustafsson²,

Eriksson³

et al. 2000

ApJ

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We have observed the intermediate regions of the circumstellar envelope of Mira (o Ceti) in photospheric light scattered by three vibration-rotation transitions of the fundamental band of CO, from lowexcited rotational levels of the ground vibrational state, at an angular distance of b D 2@@È7A away from the star. The data were obtained with the Phoenix spectrometer mounted on the 4 m Mayall telescope at Kitt Peak. The spatial resolution is approximately and seeing limited. Our observations provide 0A .5 absolute Ñuxes, leading to an independent new estimate of the mass-loss rate of approximately 3 ] 10~7 yr~1, as derived from a simple analytic wind model. We Ðnd that the scattered intensity from the M _ wind of Mira for decreases as b~3, which suggests a time constant mass-loss rate, when 2@@ [ b [ 7@@ averaged over 100 yr, over the past 1200 yr.

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“…The modeling code used for this purpose, based on the work of WolÐre & Cassinelli (1986), calculates the equilibrium temperature of the dust shell as a function of the distance from the star (assumed to be a blackbody). A wide range of optical properties of dust grains and density distributions of dust shells can be modeled, as is described in more detail in Danchi et al (1994) and Monnier et al (1997). As R Aqr has an oxygen-rich atmosphere, it is appropriate to use optical constants for astronomical silicates, while the grain size distribution follows that of Mathis, Rumpl, & Nordsieck (1977) with dust opacities calculated assuming spheroidal Mie scattering using a method developed by Toon & Ackerman (1981).…”

Section: Mid-infrared V Isibility Measurementsmentioning

confidence: 99%

Near‐ and Mid‐Infrared Subarcsecond Structure of the Dusty Symbiotic Star R Aquarii

Tuthill

Danchi

Hale

et al. 2000

ApJ

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The results of a high-resolution interferometric campaign targeting the symbiotic long-period variable (LPV) R Aqr are reported. With both near-infrared measurements on baselines out to 10 m and midinfrared data extending to 32 m, we have been able to measure the characteristic sizes of regions from the photosphere of the LPV and its extended molecular atmosphere out to the cooler circumstellar dust shell. The near-infrared data were taken using aperture-masking interferometry on the Keck I telescope and show R Aqr to be partially resolved for wavelengths out to 2.2 km but with a marked enlargement, possibly due to molecular opacity, at 3.1 km. Mid-infrared interferometric measurements were obtained with the Univeristy of California, Berkeley, infrared spatial interferometer (ISI) operating at 11.15 km from 1992 to 1999. Although this data set is somewhat heterogeneous with incomplete coverage of the Fourier plane and sampling of the pulsation cycle, clear changes in the mid-infrared brightness distribution were observed, both as a function of position angle on the sky and as a function of pulsation phase. Spherically symmetric radiative transfer calculations of uniform-outÑow dust shell models produce brightness distributions and spectra which partially explain the data ; however, limitations to this approximation are noted. Evidence for signiÐcant deviation from circular symmetry was found in the mid-infrared and more tentatively at 3.08 km in the near-infrared ; however, no clear detection of binarity or of non-LPV elements in the symbiotic system is reported.

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Characteristics of dust shells around 13 late-type stars

Cited by 338 publications

References 0 publications

The effect of dust obscuration in RR Telescopii on optical and IR long-term photometry and Fe II emission lines

The effect of dust obscuration in RR Telescopii on optical and IR long-term photometry and Fe II emission lines

Mira’s Wind Explored in Scattering Infrared CO Lines

Near‐ and Mid‐Infrared Subarcsecond Structure of the Dusty Symbiotic Star R Aquarii

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