CCD photometry and model of MUSES-C target (25143) 1998 SF36

Kaasalainen, M.; Kwiatkowski, T.; Abe, Masanao; Piironen, J.; Nakamura, T.; Ohba, Youhei; Dermawan, Budi; Farnham, T. L.; Colas, François; Lowry, S. C.; Weissman, P. R.; Whiteley, Robert J.; Tholen, David J.; Larson, S. M.; Yoshikawa, Makoto; Tóth, I.; Velichko, F. P.

doi:10.1051/0004-6361:20030819

Cited by 52 publications

(47 citation statements)

References 8 publications

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“…Kaasalainen et al (2003 present photometry and an analysis yielding estimates of the asteroid's sidereal spin period, P = 12.132 ± 0.0005 hr, and pole direction: ecliptic long., lat. = 355°, −84°± 5°.…”

Section: Introductionmentioning

confidence: 90%

“…We present a preliminary estimate of Itokawa's shape, reconstructed from images with rather limited rotation-phase coverage, using the method of Hudson (1993) and assuming the lightcurve-derived spin period (12.132 hr) and pole direction (ecliptic long., lat. = 355°, −84°) of Kaasalainen et al (2003). The model can be described as a slightly asymmetrical, slightly flattened ellipsoid with extents along its principal axes of 548 × 312 × 276 m ± 10%.…”

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confidence: 99%

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Radar observations of asteroid 25143 Itokawa (1998 SF36)

Ostro

Benner

Nolan

et al. 2004

Meteorit & Planetary Scien

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Abstract-We observed 25143 Itokawa, the target of Japan's Hayabusa (MUSES-C) sample-return mission, during its 2001 close approach at Arecibo on twelve dates during March 18-April 9 and at Goldstone on nine dates during March 20-April 2. We obtained delay-Doppler images with range resolutions of 100 ns (15 m) at Arecibo and 125 ns (19 m) at Goldstone. Itokawa's average circular polarization ratio at 13 cm, 0.26 ± 0.04, is comparable to that of Eros, so its cm-to-m surface roughness probably is comparable to that on Eros. Itokawa's radar reflectivity and polarization properties indicate a near-surface bulk density within 20% of 2.5 g cm −3 . We present a preliminary estimate of Itokawa's shape, reconstructed from images with rather limited rotation-phase coverage, using the method of Hudson (1993) and assuming the lightcurve-derived spin period (12.132 hr) and pole direction (ecliptic long., lat. = 355°, −84°) of Kaasalainen et al. (2003). The model can be described as a slightly asymmetrical, slightly flattened ellipsoid with extents along its principal axes of 548 × 312 × 276 m ± 10%. Itokawa's topography is very subdued compared to that of other asteroids for which spacecraft images or radar reconstructions are available. Similarly, gravitational slopes on our Itokawa model average only 9° and everywhere are less than 27°. The radar-refined orbit allows accurate identification of Itokawa's close planetary approaches through 2170. If radar ranging planned for Itokawa's 2004 apparition succeeds, then tracking of Hayabusa during its 2005 rendezvous should reveal Yarkovsky perturbation of the asteroid's orbit.

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Section: Introductionmentioning

confidence: 90%

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confidence: 99%

Radar observations of asteroid 25143 Itokawa (1998 SF36)

Ostro

Benner

Nolan

et al. 2004

Meteorit & Planetary Scien

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“…A physical model of Itokawa was derived from its photometric lightcurves by Kaasalainen et al (2003aKaasalainen et al ( , 2008. No YORP effect was detected and the derived spin state and global shape agreed well with the real shape revealed by the Hayabusa mission (Fujiwara et al 2006;Abe et al 2006).…”

Section: (25143) Itokawamentioning

confidence: 99%

New photometric observations of asteroids (1862) Apollo and (25143) Itokawa – an analysis of YORP effect

Ďurech¹,

Vokrouhlický²,

Kaasalainen

et al. 2008

A&A

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Aims. Asteroid (1862) Apollo is one of two asteroids in which the YORP effect was detected. We carried out new photometric observations of Apollo in April 2007 to enlarge the time line and to derive a more precise shape and spin state model. We also observed another YORP-candidate, asteroid (25143) Itokawa, in December 2006 and January 2007 to obtain a longer time line. An estimation of the YORP strength on Itokawa based on its precise shape model from the Hayabusa mission predicted the deceleration to be already observable during the 2007 apparition. Methods. We used the lightcurve inversion method to model the shape and spin state of Apollo. For Itokawa, the shape and pole direction are known to a high degree of accuracy from the Hayabusa mission, so we used a modified version of lightcurve inversion with only two free parameters -the rotation period and its linear change in time.Results. The new model of Apollo confirms earlier results. The observed acceleration of Apollo's rotation rate is (5.5 ± 1.2) × 10 −8 rad d −2 , which is in agreement with the theoretically predicted value. For Itokawa, the theoretical YORP value is sensitive to the resolution of the shape model and lies in the range from −2 to −3 × 10 −7 rad d −2 . This is inconsistent with results of lightcurve inversion that place an upper limit to the change of Itokawa's rotation rate ∼1.5 × 10 −7 rad d −2 .

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“…We note that such elongation does not set any particular constraint on the execution of a sample return mission. It is worth noting that the NEA (25143) Itokawa, target of the Hayabusa sample return mission, is even more elongated (e.g., Kaasalainen et al 2003;Demura et al 2006).…”

Section: Hamentioning

confidence: 99%

An investigation of the low-ΔV near-Earth asteroids (341843) 2008 EV5 and (52381) 1993 HA

Perna

Popescu

Monteiro

et al. 2016

A&A

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Context. The Asteroid Redirect Mission (ARM) under development by NASA is being planned to collect a multi-meter boulder from a near-Earth asteroid (NEA), and to bring it to the cis-lunar space in the mid-2020's for future study and exploitation by a crewed mission. The MarcoPolo-M5 project is being proposed in 2016 for the M5 mission opportunity by ESA, to bring back to Earth a sample from a very primitive D-type NEA. As D-types are very rare within the NEA population, considerable effort is still in progress to characterize easily accessible targets with unknown surface composition, in order to discover further asteroids that belong to this taxonomic group. Aims. We aim to further characterize the physical properties of two optimal targets for sample return space missions, the low-∆V NEAs (341843) 2008 EV5 and (52381) 1993 HA. The asteroid 2008 EV5 is the baseline target of ARM, but only one spectrum of this object exists in the literature. The asteroid 1993 HA is a very favourable target for a space mission based on its dynamical properties: here we intend to assess if it is a suitable target for MarcoPolo-M5. Methods. We obtained visible spectroscopy of 2008 EV5 with the FORS2 instrument at ESO-VLT (Paranal, Chile), at different rotational phases. We also obtained visible and near-infrared spectroscopy of 1993 HA, using the EFOSC2 and SOfI instruments at ESO-NTT (La Silla, Chile). Visible photometry of 1993 HA was carried out within the IMPACTON project at the Observatório Astronômico do Sertão de Itaparica (Itacuruba, Brazil). Results. Our new observations are in agreement with the C-type classification of 2008 EV5, which is a requirement for the ARM mission. We obtained five visible spectra which do not show any variability within the limits of noise, suggesting a homogeneous surface. We obtained the first ever spectroscopic dataset (∼0.4-1.6 µm) for 1993 HA, finding a featureless, red-sloped behaviour typical of D-types (a T or X classification is also possible, with decreasing confidence). We also found that the synodic rotation period of 1993 HA is 4.107±0.002 h, a value that is optimal for the execution of a sample return mission. The derived lightcurve also suggests an elongated shape (axis ratio a/b≥1.71). At this stage 1993 HA does indeed seem to be the most favourable target for MarcoPolo-M5, though future observations are necessary to study it further.

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CCD photometry and model of MUSES-C target (25143) 1998 SF36

Cited by 52 publications

References 8 publications

Radar observations of asteroid 25143 Itokawa (1998 SF36)

Radar observations of asteroid 25143 Itokawa (1998 SF36)

New photometric observations of asteroids (1862) Apollo and (25143) Itokawa – an analysis of YORP effect

An investigation of the low-ΔV near-Earth asteroids (341843) 2008 EV5 and (52381) 1993 HA

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