Classification of asteroids using G-mode analysis

Barucci, M. A.; Capria, M. T.; Coradini, A.; Fulchignoni, M.

doi:10.1016/0019-1035(87)90177-1

Cited by 133 publications

(100 citation statements)

References 28 publications

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“…Photometry of 89 Julia yields a synodic period of 11.387 ± 0.002 hours (Schober and Lustig (1975)). Multivariate statistics classified the asteroid as part of the S cluster (Barucci et al (1987), Tholen, (1989)). The mineralogical classification of the S-type asteroids (Gaffey et al (1993)) based on the ECAS data and 52-Color spectrophotometric Survey (Bell et al (1988)) data assigns 89 Julia (together with the asteroid 9 Metis) as 'ungrouped' S-asteroids.…”

Section: Juliamentioning

confidence: 99%

Near-IR spectroscopy of asteroids , , , and , potential targets for the Rosetta mission; remote observations campaign on IRTF

et al. 2004

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In the frame of the international campaign to observe potential target asteroids for the Rosetta mission, remote observations have been carried out between Observatoire de Paris, in Meudon-France, and the NASA Infrared Telescope Facility on Mauna Kea. The SpeX instrument was used in the 0.8-2.5 microns spectral region, for two observing runs in March and June 2003. This paper presents near-IR spectra of the asteroids 21 Lutetia, 89 Julia, 140 Siwa, 2181 Fogelin, and 5480 (1989YK8).Near-IR spectra of the asteroids 21 Lutetia and 140 Siwa are flat and featureless. The spectrum of 89 Julia reveals absorption bands around 1 and 2 microns, which may indicate the presence of olivine and olivine-pyroxene mixtures and confirm the S-type designation.The small main-belt asteroids 2181 Fogelin and 5480 (1989YK8) are investigated spectroscopically for the first time. Near-IR spectra of these asteroids also Preprint submitted to New Astronomy 1 May 2018show an absorption feature around 1 micron, which could be and indicator of igneous/metamorphic surface of the objects; new observations in visible as well as thermal albedo data are necessary to draw a reliable conclusion on the surface mineralogy of both asteroids.

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Section: Juliamentioning

confidence: 99%

Near-IR spectroscopy of asteroids , , , and , potential targets for the Rosetta mission; remote observations campaign on IRTF

et al. 2004

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“…Photometry and spectroscopy in the visible show that it is primitive. It has received different spectral classifications from various authors: P-type (Tholen 1989), C0-type (Barucci et al 1987), Xc-type (Bus 1999), C-type (Lazzaro et al 2004), and Xk-type (DeMeo et al 2009). The spectrum, featureless longward of 0.5 μm with a spectral slope S V = 0.95%/1000 Å (Licandro et al 2008) and its low albedo (p V ∼ 0.05, Müller & Bloemmaert 2004) confirm that it is a primitive asteroid that belong to the C-complex defined by Tholen (1989).…”

Section: Introductionmentioning

confidence: 99%

(65) Cybele: detection of small silicate grains, water-ice, and organics

Licandro

Campins

Kelley

et al. 2010

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Context. (65) Cybele is the most representative member of a population of primitive asteroids in the outer edge of the main belt, the Cybele asteroids. Recent dynamical models suggest that a significant fraction of them originated in the primordial transneptunian disk, so the study of the physical properties of these asteroids is potentially a useful test of these models. Aims. Our aim is to obtain information on the surface composition of this asteroid. In particular we want to obtain information on the composition and properties of the regolith and the possible presence of ices and organic materials. Methods. We present 2-4 μm and 5-14 μm spectroscopy of (65) Cybele obtained with the NASA IRTF telescope and Spitzer Space Telescope respectively. We compare the results with spectra of Trojan asteroids and asteroid (24) Themis. We analyze the 2-4 μm spectrum using scattering models and we apply thermal models to the 5-14 μm data. Results. The 2-4 μm spectrum of (65) Cybele presents an absorption band centered at ∼3.1 μm and more weaker bands in the 3.2-3.6 μm region, very similar to those observed in (24) Themis. No hydrated silicates are detected. From the spectrum in the 5-14 μm region an effective diameter D = 290 ± 5 km, a beaming paramete η = 0.967 ± 0.014, and a geometric visible albedo p V = 0.05 ± 0.01 are derived using the NEATM thermal model. The emisivity spectrum in the 5-14 μm range exhibits an emission plateau at about 9 to 12 μm with an spectral contrast of ∼5%. This emission is similar to that of Trojan asteroids and active comets and may be due to small silicate grains being imbedded in a relatively transparent matrix, or to a very under-dense (fairy-castle) surface structure. The lower amplitude of the silicate emission in Cybele's spectrum with respect to that of Trojan asteroids could be attributed to larger dust particles and/or a slightly denser structure. Conclusions. The surface of (65) Cybele is covered by a fine anhydrous silicate grains mantle, with a small amount of water ice and complex organic solids. This is similar to comet surface where non-equilibrium phases coexist. The presence of water-ice and anhydrous silicates is indicative that hydration did not happened or is incomplete, suggesting that the temperatures were always sufficiently low.

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“…Using ECAS data (Zellner et al 1985), (21) Lutetia was classified by Barucci et al (1987) and Tholen (1989) as an M-type because of its high IRAS albedo (0.221 ± 0.020) and was considered to have a metallic composition. Radio investigations of the asteroid show a low value of the radar albedo (0.17 ± 0.07), more typical to C-type rather than those of M-type asteroids (Magri et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Near infra-red spectroscopy of the asteroid 21 Lutetia

Nedelcu

Birlan²,

Vernazza³

et al. 2007

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Aims. In the framework of the ground-based science campaign dedicated to the encounter with the Rosetta spacecraft, the mineralogy of the asteroid (21) Lutetia was investigated. Methods. Near-infrared (NIR) spectra of the asteroid in the 0.8−2.5 µm spectral range were obtained with SpeX/IRTF in remote observing mode from Meudon, France in March and April 2006. We analysed these data together with previously acquired spectra -March 2003, August 2004. I-band relative photometric data obtained on 20 January 2006 using the 105 cm telescope from Pic du Midi, France has been used to build the ephemeris for physical observations. A χ 2 test using meteorite spectra from the RELAB database was performed in order to find the best fit of complete visible + infrared (VNIR) spectra of Lutetia. Results. The new spectra reveal no absorption features. We find a clear spectral variation (slope), and a good correspondence between spectral variations and rotational phase. Two of the most different spectra correspond to two opposite sides of the asteroid (sub-Earth longitude difference around 180 • ). For the neutral spectra a carbonaceous chondrite spectrum yields the best fit, while for those with a slightly positive slope the enstatitic chondrite spectra are the best analog. Based on the chosen subset of the meteorite samples, our analysis suggests a primitive, chondritic nature for (21) Lutetia. Differences in spectra are interpreted in terms of the coexistence of several lithologies on the surface where the aqueous alteration played an important role.

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Classification of asteroids using G-mode analysis

Cited by 133 publications

References 28 publications

Near-IR spectroscopy of asteroids , , , and , potential targets for the Rosetta mission; remote observations campaign on IRTF

Near-IR spectroscopy of asteroids , , , and , potential targets for the Rosetta mission; remote observations campaign on IRTF

(65) Cybele: detection of small silicate grains, water-ice, and organics

Near infra-red spectroscopy of the asteroid 21 Lutetia

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