Hayabusa2 extended mission: New voyage to rendezvous with a small asteroid rotating with a short period

Hirabayashi, Masatoshi; Mimasu, Yuya; Sakatani, Naoya; Watanabe, S.; Tsuda, Yuichi; Saiki, Takanao; Kikuchi, Shota; Kouyama, T.; Yoshikawa, Makoto; Tanaka, Satoshi; Nakazawa, Shozo; Takei, Yuto; Terui, Fuyuto; Takeuchi, Hiroshi; Fujii, Atsushi; Iwata, T.; Tsumura, Kohji; Matsuura, Shuji; Shimaki, Y.; Urakawa, Seitaro; Ishibashi, Yoshihiro; Hasegawa, Susumu; Ishiguro, Masateru; Kuroda, D.; Okumura, Shin-ichiro; Sugita, Seiji; Okada, T.; Kameda, Shingo; Kamata, Shunichi; Higuchi, Arika; Senshu, Hiroki; Noda, Hirotomo; Matsumoto, Koji; Suetsugu, Ryo; Hirai, Takayuki; Kitazato, K.; Farnocchia, Davide; Naidu, Shantanu P.; Tholen, David J.; Hergenrother, C. W.; Whiteley, Robert J.; Moskovitz, Nicholas; Abell, P. A.

doi:10.1016/j.asr.2021.03.030

Cited by 27 publications

(10 citation statements)

References 147 publications

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“…Future observations of ZL polarization spectra in the visible and near-infrared will help us understand the structural and physical properties of IPD. At the same time, the heliocentric IPD distribution will be observed by ZL observation from outside the Earth's orbit (0.7-1.5 au) by the Hayabusa-2 extended mission (Hirabayashi et al 2021). These missions will allow us to better probe the IPD origin.…”

Section: Discussionmentioning

confidence: 91%

Polarization spectrum of near infrared zodiacal light observed with CIBER

Takimoto,

Arai,

Matsuura

et al. 2021

Preprint

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We report the first measurement of the zodiacal light (ZL) polarization spectrum in the near-infrared between 0.8 and 1.8 µm. Using the low-resolution spectrometer (LRS) on board the Cosmic Infrared Background Experiment (CIBER), calibrated for absolute spectrophotometry and spectropolarimetry, we acquire long-slit polarization spectral images of the total diffuse sky brightness towards five fields. To extract the ZL spectrum, we subtract contribution of other diffuse radiation, such as the diffuse galactic light (DGL), the integrated star light (ISL), and the extragalactic background light (EBL). The measured ZL polarization spectrum shows little wavelength dependence in the near-infrared and the degree of polarization clearly varies as a function of the ecliptic coordinates and solar elongation. Among the observed fields, the North Ecliptic Pole shows the maximum degree of polarization of ∼ 20%, which is consistent with an earlier observation from the Diffuse Infrared Background Experiment (DIRBE) aboard on the Cosmic Background Explorer (COBE). The measured degree of polarization and its solar elongation dependence are reproduced by the empirical scattering model in the visible band and also by the Mie scattering model for large absorptive particles, while the Rayleigh scattering model is ruled out. All of our results suggest that the interplanetary dust is dominated by large particles.

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Section: Discussionmentioning

confidence: 91%

Polarization spectrum of near infrared zodiacal light observed with CIBER

Takimoto,

Arai,

Matsuura

et al. 2021

Preprint

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“…In 2020 December, we observed asteroid 1998 KY 26 -a potential Yarkovsky detection candidate and the target of the Hayabusa2 extended mission (Hirabayashi et al 2021)-with the Very Large Telescope (VLT; MPEC 2020-X181) 17 with the purpose of improving the measurement of the orbit. At the same time, we also submitted two previously unreported observations from Maunakea in 2002 to the Minor Planet Center.…”

Section: Asteroids With Excess Nongravitational Accelerationmentioning

confidence: 99%

“…It was announced in 2020 September that Hayabusa2 will visit 1998 KY 26 after performing two swing-by maneuvers at Earth in the extended mission (Hirabayashi et al 2021). The spacecraft is equipped (Watanabe et al 2017) with a suite of instruments, the first being an optical navigation camera with one telescopic and two wide-angle cameras with seven filters at 0.39 μm (ul-band), 0.48 μm (b-band), 0.55 μm (v-band), 0.59 μm (Na), 0.70 μm (x-band), 0.86 μm (w-band), and 0.95 μm (p-band; Kameda et al 2015Kameda et al , 2017Suzuki et al 2018;Tatsumi et al 2019).…”

Section: Follow-up Observationsmentioning

confidence: 99%

Dark Comets? Unexpectedly Large Nongravitational Accelerations on a Sample of Small Asteroids

Seligman¹,

Farnocchia²,

Micheli³

et al. 2023

Planet. Sci. J.

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We report statistically significant detections of nonradial, nongravitational accelerations based on astrometric data in the photometrically inactive objects 1998 KY26, 2005 VL1, 2016 NJ33, 2010 VL65, 2016 RH120, and 2010 RF12. The magnitudes of the nongravitational accelerations are greater than those typically induced by the Yarkovsky effect, and there is no radiation-based, nonradial effect that can be so large. Therefore, we hypothesize that the accelerations are driven by outgassing and calculate implied H2O production rates for each object. We attempt to reconcile outgassing-induced acceleration with the lack of visible comae or photometric activity via the absence of surface dust and low levels of gas production. Although these objects are small, and some are rapidly rotating, the surface cohesive forces are stronger than the rotational forces, and rapid rotation alone cannot explain the lack of surface debris. It is possible that surface dust was removed previously, perhaps via outgassing activity that increased the rotation rates to their present-day value. We calculate dust production rates of order ∼10−4 g s−1 in each object, assuming that the nuclei are bare, within the upper limits of dust production from a sample stacked image of 1998 KY26 of M ̇ Dust < 0.2 g s−1. This production corresponds to brightness variations of order ∼0.0025%, which are undetectable in extant photometric data. We assess the future observability of each of these targets and find that the orbit of 1998 KY26—which is also the target of the extended Hayabusa2 mission—exhibits favorable viewing geometry before 2025.

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“…Hayabusa2 then took off for another journey into deep space. JAXA is currently planning a yby of the asteroid 2001 CC 21 in July 2026 and a rendezvous with asteroid 1998 KY 26 in July 2031 for the spacecraft's extended mission (Hirabayashi et al, 2021;Mimasu et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Inflight calibration of the Optical Navigation Camera for the Extended Mission Phase of Hayabusa2

Kouyama

Yumoto

Tatsumi

et al. 2022

Preprint

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After delivering its sample capsule to Earth, the Hayabusa2 spacecraft started its extended mission to perform a flyby of asteroid 2001 CC21 in 2026 and rendezvous with asteroid 1998 KY26 in 2031. During the extended mission, the optical navigation camera (ONC) of Hayabusa2 will play an important role in navigation and science observations, but it has suffered from optical deterioration after the spacecraft’s surface contact with and sampling of asteroid Ryugu. Furthermore, the sensitivity of the telescopic camera (ONC-T) has continued to decrease for more than a year, posing a serious problem for the extended mission. These are problems that could potentially be encountered by other sample-return missions involving surface contact. In this study, we evaluated the long-term variation of ONC performance over the 6.5 years following the launch in 2014 to predict how it will perform during observations of the two target asteroids in its extended mission (6 and 11 years from the Earth return, respectively). Our results showed several important long-term trends in ONC performance, such as transmission, dark noise level, and hot pixels. During the long cruising period of the extended mission, we plan to observe both zodiacal light and exoplanet transits as additional science targets. The accuracy of these observations is sensitive to background noise level and stray-light contamination, so we conducted new test observations to search for the lowest stray light, which has been found to depend on spacecraft attitude. The results of these analyses and new test observations suggest that the Hayabusa2 ONC will be able to conduct cruising, flyby, and rendezvous observations of asteroids with sufficient accuracy.

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Hayabusa2 extended mission: New voyage to rendezvous with a small asteroid rotating with a short period

Abstract: Highlights1. Hayabusa2 plans its extended mission to rendezvous with 1998 KY26 in 2031. 2. We show science assessments to select the final two candidates, 1998 KY26 and 2001 AV43. 3. The mission will explore the origin and evolution of small bodies and planetary defense.

Cited by 27 publications

References 147 publications

Polarization spectrum of near infrared zodiacal light observed with CIBER

Polarization spectrum of near infrared zodiacal light observed with CIBER

Dark Comets? Unexpectedly Large Nongravitational Accelerations on a Sample of Small Asteroids

Inflight calibration of the Optical Navigation Camera for the Extended Mission Phase of Hayabusa2

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