Comets and Asteroids

Characterization of (98943) 2001 CC21, the Target of Hayabusa2#

By Keith Cowing
Status Report
astro-ph.EP
February 2, 2025
Filed under , , , , ,
Characterization of (98943) 2001 CC21, the Target of Hayabusa2#
Obtained shape model of (98943) Torifune. Left top: North Pole View (Y axis = 0◦ ). Left bottom: South Pole View (Y axis = 180◦ ). Right top: Equatorial View with Z axis rotated 0◦ . Right bottom: Equatorial View with Z axis rotated 90◦ . — astro-ph.EP

The near-Earth asteroid (98943) Torifune, previously designated 2001 CC21, is the flyby target of the Hayabusa2 extended mission, nicknamed Hayabusa2# (SHARP: Small Hazardous Asteroid Reconnaissance Probe).

The ground-based telescope observations offer a key science input for the mission’s scientific investigation. During 2022 – 2024 this asteroid was at visible apparent magnitudes brighter than 18.5, allowing for a detailed characterization using ground-based telescope observations.

We determined its rotation period P = 5.021516±0.000106 h and its absolute magnitude H = 18.78 ± 0.14 and. The large number of lightcurves allows to estimate its axes ratio, its convex shape and its pole orientation λ=301±35∘, β=89+1−6 and ϵ=5±3 which indicate a prograde rotation.

We report the semi-axis of the equivalent ellipsoid, a = 0.42+0.080.06 km, b = 0.16+0.050.04 km, and c = 0.17±0.03 km. Consequently, the volume equivalent diameter is Deq = 0.44±0.06 km . Using observations conducted simultaneously with four broadband filters, we determined (g−r)=0.663±0.022 mag, (r−i)=0.177±0.012 mag, and (i−zs)=−0.061±0.032 mag. Additionally, we found that Torifune exhibits no detectable large-scale heterogeneity. We classified the object using a high signal-to-noise ratio spectrum (over the visible and near-infrared region) as Sq-type in the Bus-DeMeo taxonomy.

We estimate a mineralogy similar to LL/L ordinary chondrites, with an ol/(ol+px) = 0.60, a Fa content of 28.5 mol%, and a Fs content of 23.4 mol%. The spectral data indicate a surface affected by moderate space weathering effects.

Marcel M. Popescu, Eri Tatsumi, Javier Licandro, Miguel R. Alarcon, Javier Rodríguez Rodríguez, Miquel Serra-Ricart, Julia de León, Joaquín Fernandez Martin, David Morate, Gabriel N. Simion, Bogdan Alexandru Dumitru, Daniel Nicolae Berteşteanu, George Pantelimon Prodan, Masatoshi Hirabayashi

Comments: Accepted for publication in PSJ, 29 page, 15 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2501.15644 [astro-ph.EP] (or arXiv:2501.15644v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2501.15644
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Related DOI:
https://doi.org/10.3847/PSJ/ada560
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Submission history
From: Marcel Popescu
[v1] Sun, 26 Jan 2025 19:03:33 UTC (6,327 KB)
https://arxiv.org/abs/2501.15644
Astrobiology,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻