The peculiar object HD 44179 /'The red rectangle'/

Cohen, Martin; Anderson, Christopher M.; Cowley, A. P.; Coyne, G. V.; Fawley, William M.; Gull, T. R.; Harlan, E. A.; Herbig, G. H.; Holden, F.; Hudson, H. S.; Jakoubek, R.; Johnson, H. M.; Merrill, K. M.; Schiffer, F. H.; Soifer, B. T.; Zuckerman, B.

doi:10.1086/153403

Cited by 169 publications

(138 citation statements)

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“…Evolved objects with trapped dust in a disc and similar viewing angles are the Red Rectangle (e.g. Cohen et al 1975Cohen et al , 2004, IRAS 20056+1834 (e.g. Menzies & Whitelock 1988;Kameswara Rao et al 2002) andIRAS 17233-4330 (e.g.…”

Section: References (A) Asplund Et Al (2009) (B) Lodders (2003)mentioning

confidence: 99%

IRAS 11472−0800: an extremely depleted pulsating binary post-AGB star

Winckel

Hrivnak

Gorlova

et al. 2012

A&A

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Aims. We focus here on one particular and poorly studied object, IRAS 11472-0800. It is a highly evolved post-asymptotic giant branch (post-AGB) star of spectral type F, with a large infrared excess produced by thermal emission of circumstellar dust. Methods. We deployed a multi-wavelength study that includes the analyses of optical and IR spectra as well as a variability study based on photometric and spectroscopic time-series. Results. The spectral energy distribution (SED) properties as well as the highly processed silicate N-band emission show that the dust in IRAS 11472-0800 is likely trapped in a stable disc. The energetics of the SED and the colour variability show that our viewing angle is close to edge-on and that the optical flux is dominated by scattered light. With photospheric abundances of [Fe/H] = −2.7 and [Sc/H] = −4.2, we discovered that IRAS 11472-0800 is one of the most chemically-depleted objects known to date. Moreover, IRAS 11472-0800 is a pulsating star with a period of 31.16 days and a peak-to-peak amplitude of 0.6 mag in V. The radial velocity variability is strongly influenced by the pulsations, but the significant cycle-to-cycle variability is systematic on a longer time scale, which we interpret as evidence for binary motion. Conclusions. We conclude that IRAS 11472-0800 is a pulsating binary star surrounded by a circumbinary disc. The line-of-sight towards the object lies close to the orbital plane, therefore the optical light is dominated by scattered light. IRAS 11472-0800 is one of the most chemically-depleted objects known so far and links the dusty RV Tauri stars to the non-pulsating class of strongly depleted objects.

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Section: References (A) Asplund Et Al (2009) (B) Lodders (2003)mentioning

confidence: 99%

IRAS 11472−0800: an extremely depleted pulsating binary post-AGB star

Winckel

Hrivnak

Gorlova

et al. 2012

A&A

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“…Dust grains absorb and scatter not only stellar photons, but also the radiation from dust and gas. In addition, interstellar dust in the diffuse interstellar medium (ISM) and in other environments that are illuminated by UV photons show photoluminescence in the red part of the spectrum, a contribution known as extended red emission (ERE, Cohen et al 1975;Witt et al 1984).…”

Section: Introductionmentioning

confidence: 99%

Dust in the diffuse interstellar medium

Siebenmorgen

Вощинников

Bagnulo

2014

A&A

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We present a model for the diffuse interstellar dust that explains the observed wavelength-dependence of extinction, emission, and the linear and circular polarisation of light. The model is set up with a small number of parameters. It consists of a mixture of amorphous carbon and silicate grains with sizes from the molecular domain of 0.5 up to about 500 nm. Dust grains with radii larger than 6 nm are spheroids. Spheroidal dust particles have a factor 1.5-3 greater absorption cross section in the far-infrared than spherical grains of the same volume do. Mass estimates derived from submillimetre observations that ignore this effect are overestimated by the same amount. In the presence of a magnetic field, spheroids may be partly aligned and polarise light. We find that polarisation spectra help to determine the upper particle radius of the otherwise rather unconstrained dust size distribution. Stochastically heated small grains of graphite, silicates, and polycyclic aromatic hydrocarbons (PAHs) are included. We tabulate parameters for PAH emission bands in various environments. They show a trend with the hardness of the radiation field that can be explained by the ionisation state or hydrogenation coverage of the molecules. For each dust component its relative weight is specified so that absolute element abundances are not direct input parameters. The model is compared to the average properties of the Milky Way, which seem to represent dust in the solar neighbourhood. It is then applied to specific sight lines towards four particular stars, with one of them located in the reflection nebula NGC 2023. For these sight lines, we present ultra-high signal-to-noise linear and circular spectro-polarimetric observations obtained with FORS at the VLT. Using prolate rather than oblate grains gives a better fit to observed spectra; the axial ratio of the spheroids is typically two and aligned silicates are the dominant contributors to the polarisation.

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“…The Red Rectangle bi-conical reflection nebula is associated with the post AGB binary star HD 44179 (Cohen et al 1975;Van Winckel et al 1995). The central object is an interacting binary with a ∼7500 K evolved primary feeding an accretion disk around the likely unevolved secondary.…”

Section: Introductionmentioning

confidence: 99%

The offset dependent behavior of narrow optical emission features in the Red Rectangle proto-planetary nebula

Wehres

Linnartz

Winckel

et al. 2011

A&A

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Context. The Red Rectangle proto-planetary nebula provides a unique laboratory to study the physical conditions and chemical processes in stellar outflows. Snapshots of the ongoing chemical evolution are obtained by monitoring spectra as function of the offset from the central star. Aims. The focus in this study is on the characterization of narrow optical emission features, that are superimposed on top of extended red emission (ERE). The primary aim is to provide a two-dimensional catalogue of these features for offsets varying from 3 to 20 from the central star. Methods. Medium resolution emission spectra for this catalogue have been obtained through optical long-slit measurements using the New Technology Telescope (EMMI-NTT) in La Silla, Chile. Results. The recorded spectra cover the range between 5550 and 6800 Å. A complete overview of the central band positions and bandwidths (FWHMs) is provided for both stronger (previously reported) and weaker narrow features. Only some bands are omnipresent in the nebula outflows and other bands only appear further away from the central star.Conclusions. The optical emission bands show intensity variations over the nebula. We suggest that these variations reflect a spatially resolved photochemistry where larger species are photolysed, producing daughter molecules which may be the carriers of the optical emission bands.

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The peculiar object HD 44179 /'The red rectangle'/

Cited by 169 publications

References 0 publications

IRAS 11472−0800: an extremely depleted pulsating binary post-AGB star

IRAS 11472−0800: an extremely depleted pulsating binary post-AGB star

Dust in the diffuse interstellar medium

The offset dependent behavior of narrow optical emission features in the Red Rectangle proto-planetary nebula

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