Olivine-rich asteroids in the near-Earth space

Popescu, M.; Perna, D.; Fornasier, S.; Doressoundiram, A.; Lantz, C.; Merlin, F.; Belskaya, I. N.; Fulchignoni, M.

doi:10.1093/mnras/sty704

Cited by 13 publications

(14 citation statements)

References 42 publications

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“…This spectral type is very rare and it is indicative of a very high olivine content (e.g. DeMeo et al 2019;Popescu et al 2018a), which is in agreement with our previous analysis.Thus, we can conclude that the most likely classification is a Sa-type.…”

Section: Spectral Propertiessupporting

confidence: 92%

Physical characterization of 2020 AV2, the first known asteroid orbiting inside Venus orbit

Popescu,

de León,

Marcos

et al. 2020

Preprint

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The first known asteroid with the orbit inside that of Venus is 2020 AV 2 . This may be the largest member of a new population of small bodies with the aphelion smaller than 0.718 au, called Vatiras. The surface of 2020 AV 2 is being constantly modified by the high temperature, by the strong solar wind irradiation that characterizes the innermost region of the Solar system, and by high-energy micrometeorite impacts. The study of its physical properties represents an extreme test-case for the science of near-Earth asteroids. Here, we report spectroscopic observations of 2020 AV 2 in the 0.5-1.5 µm wavelength interval. These were performed with the Nordic Optical Telescope and the William Herschel Telescope. Based on the obtained spectra, we classify 2020 AV 2 as a Sa-type asteroid. We estimate the diameter of this Vatira to be 1.50 +1.10 −0.65 km by considering the average albedo of A-type and S-complex asteroids (p V = 0.23 +0.11 −0.08 ), and the absolute magnitude (H=16.40 ± 0.78 mag). The wide spectral band around 1 µm shows the signature of an olivine rich composition. The estimated band centre BIC = 1.08 ± 0.02 µm corresponds to a ferroan olivine mineralogy similar to that of brachinite meteorites.

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Section: Spectral Propertiessupporting

confidence: 92%

Physical characterization of 2020 AV2, the first known asteroid orbiting inside Venus orbit

Popescu,

de León,

Marcos

et al. 2020

Preprint

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“…They found that that the distributions of NEAs with diameter below ∼ 250 m are different compared to those lager than this rough threshold. In particular, Popescu et al (2018) and Barucci et al (2018) found that the A-types and D-types are more abundant in the smaller NEOs. They used the 147 NEAs observed with New Technology Telescope within the NEOShield-2 project (Binzel et al 2019).…”

Section: Discussionmentioning

confidence: 98%

Near-Earth asteroids spectroscopic survey atIsaac NewtonTelescope

Popescu

Văduvescu

León

et al. 2019

A&A

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Context. The population of near-Earth asteroids (NEAs) shows a large variety of objects in terms of physical and dynamical properties. They are subject to planetary encounters and to strong solar wind and radiation effects. Their study is also motivated by practical reasons regarding space exploration and long-term probability of impact with the Earth. Aims. We aim to spectrally characterize a significant sample of NEAs with sizes in the range of ∼0.25 -5.5 km (categorized as large), and search for connections between their spectral types and the orbital parameters. Methods. Optical spectra of NEAs were obtained using the Isaac Newton Telescope (INT) equipped with the IDS spectrograph. These observations are analyzed using taxonomic classification and by comparison with laboratory spectra of meteorites. Results. A total number of 76 NEAs were observed. We spectrally classified 44 of them as Q/S-complex, 16 as B/C-complex, eight as V-types, and another eight belong to the remaining taxonomic classes. Our sample contains 27 asteroids categorized as potentially hazardous and 31 possible targets for space missions including (459872) 2014 EK24, (436724) 2011 UW158, and (67367) 2000 LY27. The spectral data corresponding to (276049) 2002 CE26 and (385186) 1994 AW1 shows the 0.7 µm feature which indicates the presence of hydrated minerals on their surface. We report that Q-types have the lowest perihelia (a median value and absolute deviation of 0.797 ± 0.244 AU) and are systematically larger than the S-type asteroids observed in our sample. We explain these observational evidences by thermal fatigue fragmentation as the main process for the rejuvenation of NEA surfaces. Conclusions. In general terms, the taxonomic distribution of our sample is similar to the previous studies and matches the broad groups of the inner main belt asteroids. Nevertheless, we found a wide diversity of spectra compared to the standard taxonomic types.

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“…Incidentally, two of them have already been chosen as a sample-return candidate: (101955) Bennu, target of the OSIRIS-REx mission (Lauretta et al 2017), and (175706) 1996 FG3, backup target of the ESA candidate mission MarcoPolo-R (Perna et al 2013b). In addition, we also considered three A-type PHAs in this subgroup: a type of olivine-dominated asteroid extremely rare in both the NEO population and the asteroid belt (see also Popescu et al 2018). These 25 bodies, reported in Table 8, due to their potential hazard, their peculiar spectral type, and their extreme low ∆V, represent a very good choice for the next generation of space missions towards an NEO.…”

Section: Selection Of Potential Targets Of Space Missionsmentioning

confidence: 99%

Extended photometric survey of near-Earth objects

Ieva

Dotto

Epifani

et al. 2020

A&A

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Context. The near-Earth objects (NEOs), whose proximity makes them the most accessible bodies in the Solar System, allow us to sample asteroids from tens of kilometers down to objects of a few meters in size. However, while the physical properties for the largest bodies are mostly known, we have very little physical information regarding the small NEOs. These objects today represent the overall majority among the ~2500 new discoveries each year, but they are usually only bright enough to be observable during their close approaches. Aims. Our aim was to extend our survey that started in 2015 on the NEO population, using ground-based observations to characterize the fainter (and typically smaller) NEOs observable each night. Methods. We performed BVRIz photometry of NEOs, making use of the DOLORES instrument at the Telescopio Nazionale Galileo (TNG, La Palma, Spain) and the Asiago Schmidt telescope (Italy), in order to derive visible color indexes and the taxonomic classification for each target in our sample. Results. We taxonomically classified 51 new NEOs for the first time. Together with data obtained in our previous work and collected by other surveys available online, we analyzed an extended sample of 1081 individual NEOs. While the overall majority of them belong to the S-complex, our analysis of the taxonomic distribution found a larger contribution for dark bodies going toward larger H, suggesting that they could be more abundant among the fainter NEOs. Moreover, we find an interesting correlation between semi-major axis and diameter, which could be in part related to the Yarkovsky effect. Rapid characterization of the fainter NEO population shortly after their discovery will be crucial in the future, before those bodies become too faint to be observed, or lost forever.

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Olivine-rich asteroids in the near-Earth space

Cited by 13 publications

References 42 publications

Physical characterization of 2020 AV2, the first known asteroid orbiting inside Venus orbit

Physical characterization of 2020 AV2, the first known asteroid orbiting inside Venus orbit

Near-Earth asteroids spectroscopic survey atIsaac NewtonTelescope

Extended photometric survey of near-Earth objects

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