Polarization of Asteroid (387) Aquitania: The newest member of a class of large inversion angle asteroids

Masiero, J.; Cellino, A.

doi:10.1016/j.icarus.2008.10.003

Cited by 30 publications

(25 citation statements)

References 19 publications

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“…Aquitania is an L-type asteroid (or S-type in the Tholen taxonomy), Aquitania is a slow rotator, taking 24.14 hr for one revolution (Warner et al 2009). From polarimetric observations (Masiero & Cellino 2009), it is considered a member of the so-called Barbarians (Cellino et al 2006), which represent some of the oldest surfaces in the solar system. Our AKARI results show a bumpy structure at around 3.1 µm, which might come from contamination due to background stars.…”

Section: Aquitaniamentioning

confidence: 99%

AKARI/IRC near-infrared asteroid spectroscopic survey: AcuA-spec

Usui

Hasegawa

Ootsubo

et al. 2018

Publications of the Astronomical Society of Japan

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Knowledge of water in the solar system is important for understanding of a wide range of evolutionary processes and the thermal history of the solar system. To explore the existence of water in the solar system, it is indispensable to investigate hydrated minerals and/or water ice on asteroids. These water-related materials show absorption features in the 3-µm band (wavelengths from 2.7 to 3.1 µm). We conducted a spectroscopic survey of asteroids in the 3-µm band using the Infrared Camera (IRC) on board the Japanese infrared satellite AKARI. In the warm mission period of AKARI, 147 pointed observations were performed for 66 asteroids in the grism mode for wavelengths from 2.5 to 5 µm. According to these observations, most C-complex asteroids have clear absorption features (> 10% with respect to the continuum) related to hydrated minerals at a peak wavelength of approximately 2.75 µm, while S-complex asteroids have no significant feature in this wavelength range. The present data are released to the public as the Asteroid Catalog using AKARI Spectroscopic Observations (AcuA-spec).

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Section: Aquitaniamentioning

confidence: 99%

AKARI/IRC near-infrared asteroid spectroscopic survey: AcuA-spec

Usui

Hasegawa

Ootsubo

et al. 2018

Publications of the Astronomical Society of Japan

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“…6). This group of moderate-albedo asteroids of spectral type L, K or Ld have anomalous polarization properties which may be related to their specific surface composition (Cellino et al 2006;Gil-Hutton et al 2008;Masiero & Cellino 2009). We note, that the polarization minimum value of these asteroids deviates considerably from the well-known correlation "P min -albedo" and cannot be used for albedo estimation.…”

Section: Polarimetrymentioning

confidence: 99%

Puzzling asteroid 21 Lutetia: our knowledge prior to the Rosetta fly-by

Belskaya

Fornasier

Krugly

et al. 2010

A&A

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Aims. A wide observational campaign was carried out in [2004][2005][2006][2007][2008][2009] that aimed to complete the ground-based investigation of Lutetia prior to the Rosetta fly-by in July 2010. Methods. We obtained BVRI photometric and V-band polarimetric measurements over a wide range of phase angles, and visible and infrared spectra in the 0.4-2.4 μm range. We analyze them with previously published data to retrieve information about Lutetia's surface properties.Results. Values of lightcurve amplitudes, absolute magnitude, opposition effect, phase coefficient, and BVRI colors of Lutetia surface seen at near pole-on aspect are determined. We define more precisely parameters of polarization phase curve and show their distinct deviation from any other moderate-albedo asteroid. An indication of possible variations in both polarization and spectral data across the asteroid surface are found. To explain features found by different techniques, we propose that (i) Lutetia has a non-convex shape, probably due to a large crater, and heterogeneous surface properties probably related to surface morphology; (ii) at least part of the surface is covered by a fine-grained regolith of particle size smaller than 20 μm; (iii) the closest meteorite analogues of Lutetia's surface composition are particular types of carbonaceous chondrites, or Lutetia has specific surface composition that is not representative among studied meteorites.

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“…Because (234) Barbara had been classified as Ld in the SMASS taxonomy, other asteroids of this or similar taxonomic classes were subsequently observed and 18 objects sharing the same polarimetric behaviour of Barbara were found by Gil-Hutton et al (2008), Masiero and Cellino (2009), Gil-Hutton and Cañada-Assandri (2011), Gil-Hutton et al (2014), Cellino et al (2014a), Bagnulo et al (2015), and Devogèle et al (2017a). They were collectively named Barbarians after the asteroid (234) Barbara.…”

Section: Introductionmentioning

confidence: 99%

New polarimetric and spectroscopic evidence of anomalous enrichment in spinel-bearing calcium-aluminium-rich inclusions among L-type asteroids

Devogèle

Tanga

Cellino

et al. 2018

Icarus

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Asteroids can be classified into several groups based on their spectral reflectance. Among these groups, the one belonging to the L-class in the taxonomic classification based on visible and near-infrared spectra exhibit several peculiar properties. First, their near-infrared spectrum is characterized by a strong absorption band interpreted as the diagnostic of a high content of the FeO bearing spinel mineral. This mineral is one of the main constituents of Calcium-Aluminum-rich Inclusions (CAI) the oldest mineral compounds found in the solar system. In polarimetry, they possess an uncommonly large value of the inversion angle incompatible with all known asteroid belonging to other taxonomical classes. Asteroids found to possess such a high inversion angle are commonly called Barbarians based on the first asteroid on which this property was first identified, (234) Barbara. In this paper we present the results of an extensive campaign of polarimetric and spectroscopic observations of L-class objects. We have derived phase-polarization curves for a sample of 7 Barbarians, finding a variety of inversion angles ranging between 25 and 30 • . Spectral reflectance data exhibit variations in terms of spectral slope and absorption features in the near-infrared. We analyzed these data using a Hapke model to obtain some inferences about the relative abundance of CAI and other mineral compounds. By combining spectroscopic and polarimetric results, we find evidence that the polarimetric inversion angle is directly correlated with the presence of CAI, and the peculiar polarimetric properties of Barbarians are primarily a consequence of their anomalous composition.

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Polarization of Asteroid (387) Aquitania: The newest member of a class of large inversion angle asteroids

Cited by 30 publications

References 19 publications

AKARI/IRC near-infrared asteroid spectroscopic survey: AcuA-spec

AKARI/IRC near-infrared asteroid spectroscopic survey: AcuA-spec

Puzzling asteroid 21 Lutetia: our knowledge prior to the Rosetta fly-by

New polarimetric and spectroscopic evidence of anomalous enrichment in spinel-bearing calcium-aluminium-rich inclusions among L-type asteroids

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