Linear and circular polarization of comet C/2009 P1 (Garradd)

Kiselev, N. N.; Rosenbush, V. K.; Afanasiev, V. L.; Колесников, С. В.; Zaitsev, S. V.; Shakhovskoy, D. N.

doi:10.5047/eps.2013.05.014

Cited by 13 publications

(5 citation statements)

References 16 publications

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“…The observation technique provides a series of information simultaneously on the polarization degrees (P) of both the gas (P gas ) and dust components (P cont ) as well as the position angle (θ P ) with respect to the normal vector of the scattering plane (θ r ). However, only few studies in the published literature have reported the spectropolarimetric results of comets (Borisov et al 2015;Kiselev et al 2013;Myers & Nordsieck 1984).…”

Section: Introductionmentioning

confidence: 99%

High polarization degree of the continuum of comet 2P/Encke based on spectropolarimetric signals during its 2017 apparition

Kwon

Ishiguro

Shinnaka

et al. 2018

A&A

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Context. Spectropolarimetry is a powerful technique for investigating the physical properties of gas and solid materials in cometary comae without mutual contamination, but there have been few spectropolarimetric studies to extract each component. Aims. We attempt to derive the continuum (i.e., scattered light from dust coma) polarization degree of comet 2P/Encke, free from influence of molecular emissions. The target is unique in that it has an orbit dynamically decoupled from Jupiter like main-belt asteroids, while ejecting gas and dust like ordinary comets. Methods. We observed the comet using the Higashi-Hiroshima Optical and Near-Infrared Camera attached to the Cassegrain focus of the 150-cm Kanata telescope on UT 2017 February 21 when the comet was at the solar phase angle of α=75 • .7. Results. We find that the continuum polarization degree with respect to the scattering plane is P cont,r =33.8±2.7 % at the effective wavelength of 0.815 µm, which is significantly higher than those of cometary dust in a high-P max group at similar phase angles. Assuming that an ensemble polarimetric response of 2P/Encke's dust as a function of phase angle is morphologically similar with those of other comets, its maximum polarization degree is estimated to P max 40 % at α max ≈100 • . In addition, we obtain the polarization degrees of the C 2 swan bands (0.51-0.56 µm), the NH 2 α bands (0.62-0.69 µm) and the CN-red system (0.78-0.94 µm) in a range of 3-19 %, which depend on the molecular species and rotational quantum numbers of each branch. The polarization vector aligns nearly perpendicularly to the scattering plane with the average of 0 • .4 over a wavelength range of 0.50-0.97 µm. Conclusions. From the observational evidence, we conjecture that the large polarization degree of 2P/Encke would be attributable to a dominance of large dust particles around the nucleus, which have remained after frequent perihelion passages near the Sun.

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Section: Introductionmentioning

confidence: 99%

High polarization degree of the continuum of comet 2P/Encke based on spectropolarimetric signals during its 2017 apparition

Kwon

Ishiguro

Shinnaka

et al. 2018

A&A

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“…A detailed description of the SCORPIO-1 and SCORPIO-2 and the technique of observations, the image processing, reduction, errors estimation, and the method of calculation of polarization parameters in different modes of the instruments are also described in (Kiselev et al 2013;Afanasiev, Rosenbush & Kiselev 2014;Ivanova et al 2017;Rosenbush et al 2020).…”

Section: Spectropolarimetry and Imaging Polarimetrymentioning

confidence: 99%

Asteroid (3200) Phaethon: results of polarimetric, photometric, and spectral observations

Kiselev

Rosenbush

Петров

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We present results of polarimetric, photometric, and spectral observations of the near-Earth asteroid (3200) Phaethon carried out at the 6-m BTA telescope of the Special Astrophysical Observatory and the 2.6-m and 1.25-m telescopes of the Crimean Astrophysical Observatory over a wide range of phase angles during its close approach to the Earth at the end of 2017 (α = 19° – 135°) and in 2020 at α = 52.2°. Using our and other available in literature data, we found that the maximum degree of linear polarization of Phaethon in the V band is Pmax = (45 ± 1)% at the phase angle αmax = 124.0° ± 0.4°, whereas the inversion angle αinv = 21.4° ± 1.2° and polarimetric slope is h = (0.326 ± 0.027) %/deg. Using the dependence “polarimetric slope – albedo,” we have found the geometric albedo of asteroid Phaethon to be pv = 0.060 ± 0.005. This value falls into the lower range of albedo values for asteroids determined by different methods. The mean color indices U–B = 0.207 m ± 0.053 m and B–V = 0.639 m ± 0.054 m of the asteroid are derived at heliocentric and geocentric distances 1.077 au and 0.102 au, respectively, and phase angle α = 23.78°. The absolute magnitude of Phaethon is V(1,1,0) = 14.505 m ± 0.059 m. The effective diameter of Phaethon is estimated from obtained absolute magnitude and geometrical albedo, it is equal to 6.8 ± 0.3 km. The best fit to the observed polarimetric data was obtained with the Sh-matrix model of conjugated random Gaussian particles composed of Mg-rich silicate (90%) and amorphous carbon (10%).

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“…Fig. 13 shows the measured linear polarization of comet Garradd according to data from Das et al (2013), Kiselev et al (2013), Hadamcik et al (2014), and this work. The curves 1 and 2 in the figure are the fits to all polarization data for classes of the high-P max and low-P max comets in the red, respectively, according to Kiselev et al (2015).…”

Section: Linear Polarization In Continuummentioning

confidence: 96%

“…Comet Garradd was observed during two periods: on February 2 and 14, 2012, when its heliocentric distance, r, increased from 1.64 to 1.70 au, geocentric distance, , has decreased from 1.53 to 1.39 au, and phase angle, α, was between 36° and 35° ; and on April 14 and 21, 2012, r = 2.16 ÷2.23, = 1.79 ÷1.97, and α≈27° In both periods, observations of the comet were performed at the primary focus (f/4) of the 6 m telescope BTA of the Special Astrophysical Observatory (Russia) with the multi-mode focal reducer SCORPIO-2 ( Afanasiev and Moiseev, 2011;Afanasiev and Amirkhanyan, 2012;Kiselev et al, 2013 ). The following modes of the instrument were used for observations: direct CCD images (hereafter called Image); the low-resolution linear and circular spectropolarimetry (SpPol); and imaging circular polarimetry (ImaPol).…”

Section: Instrument and Observationsmentioning

confidence: 99%

“…For several years, we have been carrying out observations of different comets with the focal reducer SCORPIO-2 mounted at the 6-m telescope of the Special Astrophysical Observatory (Russia). Some preliminary results of our long-term monitoring campaign of comet Garradd were published by Kiselev et al (2013). These data also included the results of aperture polarimetry obtained with the 2.6 m telescope of the Crimean Astrophysical Observatory.…”

Section: Introductionmentioning

confidence: 99%

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