Optical polarization in the disc around   Pictoris

Gledhill, T. M.; Scarrott, S. M.; Wolstencroft, R. D.

doi:10.1093/mnras/252.1.50p

Cited by 37 publications

(29 citation statements)

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“…The colors of the disk are relatively neutral at visible wavelengths (Paresce & Burrows 1987) suggesting that the grains must be generally larger than 1 µm. The disk of β Pic is also polarized at about 17% (Gledhill et al 1991), similar to the zodiacal light of our own solar system (Leinert et al 1982), suggesting that the dust in the β Pic disk includes grains similar to solar system interplanetary dust particles, including large (say 10 µm diameter) fluffy aggregates of submicron size components. Thus in may ways, the dusty debris disk in β Pic is similar to that in our solar system, but more massive and presumably younger.…”

Section: Introductionsupporting

confidence: 72%

Cometary Dust in the Debris Disks of HD 31648 and HD 163296: Two “Baby” β Pictoris Stars

Sitko

Grady

Lynch

et al. 1999

ApJ

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The debris disks surrounding the pre-main sequence stars HD 31648 and HD 163296 were observed spectroscopically between 3 and 14 µm. Both possess a silicate emission feature at 10 µm which resembles that of the star β Pictori and those observed in solar system comets. The structure of the band is consistent with a mixture of olivine and pyroxene material, plus an underlying continuum of unspecified origin. The similarity in both size and structure of the silicate band suggests that the material in these systems had a processing history similar to that in our own solar system prior to the time that the grains were incorporated into comets.

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Section: Introductionsupporting

confidence: 72%

Cometary Dust in the Debris Disks of HD 31648 and HD 163296: Two “Baby” β Pictoris Stars

Sitko

Grady

Lynch

et al. 1999

ApJ

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“…The accompanying AE1 error profiles, which are derived from the total-error maps of the images (x 2.2) and include $3% uncertainty in the photometric calibration, show that these profiles are very accurate beyond $1B5 ($30 AU ) from the star. The profiles clearly do not indicate a single power-law dependence of surface brightness with distance, as was determined in some of the earliest ground-based imaging studies of the disk (Smith & Terrile 1984;Artymowicz et al 1989;Gledhill et al 1991;Lecavelier des Etangs et al 1993). Instead, the logarithmic profiles exhibit distinctly different linear behavior at angular distances of 2 00 -3B5, 3B7-5B6, 6B6-10 00 , and 10 00 -13B4, with smooth transitions in slope between these regions.…”

Section: Surface Brightness and Asymmetrymentioning

confidence: 69%

“…The convex isophotes in this region indicate that the pinched appearances of the disk in the images of Smith & Terrile (1984), Golimowski et al (1993), Lecavelier des Etangs et al (1993), Mouillet et al (1997aMouillet et al ( , 1997b, and, to a lesser degree, Kalas & Jewitt (1995) are artifacts of oversubtraction of the reference PSF and/or self-subtraction of the disk along its minor axis. Other scattered-light images yielded no information in this region because of obscuration by coronagraphic masks ( Paresce & Burrows 1987;Gledhill et al 1991;Heap et al 2000). Our images are tinged by residuals from the imperfect subtraction of the linear PSF feature seen in Figure 1, but these residuals do not affect the overall contours of the isophotes.…”

Section: Image Analysismentioning

confidence: 70%

Hubble Space TelescopeACS Multiband Coronagraphic Imaging of the Debris Disk around β Pictoris

et al. 2006

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We present F435W (B), F606W ( broad V ), and F814W ( broad I ) coronagraphic images of the debris disk around Pictoris obtained with the Hubble Space Telescope's Advanced Camera for Surveys. These images provide the most photometrically accurate and morphologically detailed views of the disk between 30 and 300 AU from the star ever recorded in scattered light. We confirm that the previously reported warp in the inner disk is a distinct secondary disk inclined by $5 from the main disk. The projected spine of the secondary disk coincides with the isophotal inflections, or ''butterfly asymmetry,'' previously seen at large distances from the star. We also confirm that the opposing extensions of the main disk have different position angles, but we find that this ''wing-tilt asymmetry'' is centered on the star rather than offset from it, as previously reported. The main disk's northeast extension is linear from 80 to 250 AU, but the southwest extension is distinctly bowed with an amplitude of $1 AU over the same region. Both extensions of the secondary disk appear linear, but not collinear, from 80 to 150 AU. Within $120 AU of the star, the main disk is $50% thinner than previously reported. The surface brightness profiles along the spine of the main disk are fitted with four distinct radial power laws between 40 and 250 AU, while those of the secondary disk between 80 and 150 AU are fitted with single power laws. These discrepancies suggest that the two disks have different grain compositions or size distributions. The F606W/ F435W and F814W/ F435W flux ratios of the composite disk are nonuniform and asymmetric about both projected axes of the disk. The disk's northwest region appears 20%-30% redder than its southeast region, which is inconsistent with the notion that forward scattering from the nearer northwest side of the disk should diminish with increasing wavelength. Within $120 AU, the m F435W À m F606W and m F435W À m F814W colors along the spine of the main disk are $10% and $20% redder, respectively, than those of Pic. These colors increasingly redden beyond $120 AU, becoming 25% and 40% redder, respectively, than the star at 250 AU. These measurements overrule previous determinations that the disk is composed of neutrally scattering grains. The change in color gradient at $120 AU nearly coincides with the prominent inflection in the surface brightness profile at $115 AU and the expected waterice sublimation boundary. We compare the observed red colors within $120 AU with the simulated colors of nonicy grains having a radial number density /r À3 and different compositions, porosities, and minimum grain sizes. The observed colors are consistent with those of compact or moderately porous grains of astronomical silicate and /or graphite with sizes k0.15-0.20 m, but the colors are inconsistent with the blue colors expected from grains with porosities k90%. The increasingly red colors beyond the ice sublimation zone may indicate the condensation of icy mantles on the refractory grains, or they may reflect...

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“…The evidence of this is the main result of our program. circumstellar disk is spatially resolved and special coronographic technique of observations can be used to this purpose (Smith and Terrile, 1984;Paresce and Burrows, 1987;Gledhill et al, 1991). In our case we deal with unresolved protoplanetary disks and we should wait for the stage when the star will be screened out by a dust cloud intersecting the line of sight.…”

Section: A) H O W It Was Made?mentioning

confidence: 99%

Young stars with non-periodic algol-type minima

Гринин

1992

Astronomical & Astrophysical Transactions

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The irregular variability is one of the most important properties of young stellar objects and is of great interest since its understanding is the key to understanding the physics of young stars. The main question is: how to separate, in each concrete case, the different potentially important mechanisms of the variability, such as the variable circumstellar extinction, the flare (and chromospheric) activity, and the suppression of stellar photosphere by the formation of magnetic spots? We consider this question below in application to an interesting subclass of young stars, the stars with non-periodic Algol-type minima. The most important results of current investigations of these stars are discussed.

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Optical polarization in the disc around Pictoris

Cited by 37 publications

References 0 publications

Cometary Dust in the Debris Disks of HD 31648 and HD 163296: Two “Baby” β Pictoris Stars

Cometary Dust in the Debris Disks of HD 31648 and HD 163296: Two “Baby” β Pictoris Stars

Hubble Space TelescopeACS Multiband Coronagraphic Imaging of the Debris Disk around β Pictoris

Young stars with non-periodic algol-type minima

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