Near-IR bispectrum speckle interferometry, AO imaging polarimetry, and radiative transfer modeling of the proto-planetary nebula Frosty Leonis

Murakawa, K.; Ohnaka, K.; Driebe, T.; Hofmann, K.-H.; Oya, Shin; Schertl, D.; Weigelt, G.

doi:10.1051/0004-6361:20078623

Cited by 14 publications

(23 citation statements)

References 48 publications

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“…We find a wavelength-dependent DoP that increases towards longer wavelengths from 11% to 19% in the B and I bands, respectively, which is consistent with scattering by small dust grains (Murakawa et al 2008). The PA rotates from 55…”

Section: Iras 09371+1212supporting

confidence: 69%

Multi-band polarimetry of post-asymptotic giant branch stars – I. Optical measurements

Akras

Vélez

Nanouris

et al. 2017

Mon. Not. R. Astron. Soc.

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We present new optical broad-band (UBVRI) aperture polarimetric observations of 53 post-asymptotic giant branch (AGB) stars selected to exhibit a large nearinfrared excess. 24 out of the 53 stars (45% of our sample) are presented for the first time. A statistical analysis shows four distinctive groups of polarized post-AGB stars: unpolarized or very lowly polarized (degree of polarization or DoP<1%), lowly polarized (1% < DoP< 4%), moderately polarized (4% < DoP < 8%) and highly polarized (DoP > 8%). 23 out of the 53 (66%) belong to the first group, 10 (19%) to the second, five (9%) to the third and only three (6%) to the last group. Approximately, 34% of our sample was found to be unpolarized objects, which is close to the percentage of round planetary nebulae. On average, the low and moderate groups show a wavelength-dependent polarization that increases towards shorter wavelength, implying an intrinsic origin of the polarization, which signifies a Rayleigh-like scattering spectrum typical for non-symmetrical envelopes composed principally of small dust grains. The moderately polarized stars exhibit higher K-W3 and W1-W3 colour indices compared with the group of lowly polarized stars suggesting a possible relation between DoP and mass-loss rate. Moreover, they are found to be systematically colder (redder in B-V), which may be associated with the condensation process close to these stars that results in higher degree of polarization. We also provide evidence that multiple scattering in optically thin polar outflows is the mechanism that gives high DoP in post-AGB stars with a bipolar or multi-polar envelopes.

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Section: Iras 09371+1212supporting

confidence: 69%

Multi-band polarimetry of post-asymptotic giant branch stars – I. Optical measurements

Akras

Vélez

Nanouris

et al. 2017

Mon. Not. R. Astron. Soc.

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“…Observations of such small structures near evolved stars can only be performed with the use of high-angular resolution techniques like the infrared Very Large Telescope Interferometer (VLTI), i.e. planetary nebulae (Chesneau et al , 2007Lagadec et al 2006); VLTP star (Chesneau et al 2009); Mira stars (Tatebe et al 2006(Tatebe et al , 2007(Tatebe et al , 2008; carbon stars (Ohnaka & Boboltz 2008;Sacuto et al 2011;Deroo et al 2007b); OH/IR stars (Deroo et al 2007a,b;Chesneau et al 2005b); post-AGB stars (Deroo et al 2006;Matsuura et al 2006); proto-planetary nebulae (Murakawa et al 2008;Ohnaka et al 2006). Two of the best-studied examples of elongated and axisymmetric bipolar planetary nebulae are M2-9 and Menzel 3.…”

Section: Introductionmentioning

confidence: 99%

A disc inside the bipolar planetary nebula M2-9

Lykou

Chesneau

Zijlstra

et al. 2011

A&A

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Aims. Bipolarity in proto-planetary and planetary nebulae is associated with events occurring in or around their cores. Past infrared observations have revealed the presence of dusty structures around the cores, many in the form of discs. Characterising those dusty discs provides invaluable constraints on the physical processes that govern the final mass expulsion of intermediate mass stars. We focus this study on the famous M2-9 bipolar nebula, where the moving lighthouse beam pattern indicates the presence of a wide binary. The compact and dense dusty core in the centre of the nebula can be studied by means of optical interferometry. Methods. M2-9 was observed with VLTI/MIDI at 39-47 m baselines with the UT2-UT3 and UT3-UT4 baseline configurations. These observations are interpreted using a dust radiative transfer Monte Carlo code. Results. A disc-like structure is detected perpendicular to the lobes, and a good fit is found with a stratified disc model composed of amorphous silicates. The disc is compact, 25 × 35 mas at 8 μm and 37 × 46 mas at 13 μm. For the adopted distance of 1.2 kpc, the inner rim of the disc is ∼15 AU. The mass represents a few percent of the mass found in the lobes. The compactness of the disc puts strong constraints on the binary content of the system, given an estimated orbital period 90-120 yr. We derive masses of the binary components between 0.6-1.0 M for a white dwarf and 0.6-1.4 M for an evolved star. We present different scenarios on the geometric structure of the disc accounting for the interactions of the binary system, which includes an accretion disc as well.

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“…Furthermore, polarization analysis allows us to constrain the grain size, particularly in the nebula on a large scale better than using the SED and the Article published by EDP Sciences intensity images (e.g. Dougados et al 1990;Pendleton et al 1990;Murakawa et al 2007Murakawa et al , 2008a. In this work, we obtain NIR polarimetric images of the massive protostar CRL 2136 using the 8 m Subaru telescope and apply the above method.…”

Section: Introductionmentioning

confidence: 99%

“…This allows us to better constrain the disk structure and grain size and to analyze the dust temperature distribution, particularly in the disk. We have already performed a similar technique for the proto-planetary nebula Frosty Leo (Murakawa et al 2008a). In Sect.…”

Section: Introductionmentioning

confidence: 99%

HK-band imaging polarimetry and radiative transfer modeling of the massive young stellar object CRL 2136

Murakawa¹,

Preibisch²,

Kraus³

et al. 2008

A&A

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Aims. We investigate the physical properties of the dust environment of the massive proto-stellar object CRL 2136 by means of two-dimensional radiative transfer modeling, which combines fitting of the spectral energy distribution, the intensity images, and the polarization images. Methods. We obtained polarimetric images of CRL 2136 in the H and K bands using the CIAO instrument on the 8 m Subaru telescope. We developed a new Monte Carlo code which can deal with multiple-grain models and computes the SED, the dust temperature, and the Stokes IQUV images. With this code, we performed two-dimensional modeling of CRL 2136's circumstellar disk and envelope. Results. Our images show a compact infrared source, two bright lobes extending towards the south and east, and two faint lobes extending towards the northwest and west. The polarization images show a polarization disk near the central star with a position angle of ∼−135• , a polarization vector alignment approximately parallel to the polarization disk, and a region with low polarization between the eastern and the southern lobes. In our modeling, we assume three grain models: bare grains, warm grains with a crystalline water ice mantle, and cold grains with an amorphous water ice mantle. We obtained a maximum grain core size of 0.45 μm. We found that the CRL 2136 disk has a low disk mass of 0.007 M , a large radius of 2000 AU, a scale height of 1.0, and a low accretion rate of 2.1 × 10 −7 M yr −1 compared to an envelope mass infall rate of 1.0 × 10 −4 M yr −1 . Conclusions. The predicted environment of the disk and the envelope is consistent with a scenario in which the central star forms rapidly (∼2 × 10 5 yr), with a high mass infalling rate, and nearly isotropically (large disk scale height) in the early phase. Then, the accretion of the disk matter is prevented by the strong radiation pressure from the luminous central star, resulting in a low disk mass and a low accretion rate.

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Near-IR bispectrum speckle interferometry, AO imaging polarimetry, and radiative transfer modeling of the proto-planetary nebula Frosty Leonis

Cited by 14 publications

References 48 publications

Multi-band polarimetry of post-asymptotic giant branch stars – I. Optical measurements

Multi-band polarimetry of post-asymptotic giant branch stars – I. Optical measurements

A disc inside the bipolar planetary nebula M2-9

HK-band imaging polarimetry and radiative transfer modeling of the massive young stellar object CRL 2136

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