Interpretation of combined infrared, submillimeter, and millimeter thermal flux data obtained during the Rosetta fly-by of Asteroid (21) Lutetia

Keihm, S.; Tosi, F.; Kamp, L. W.; Capaccioni, F.; Gulkis, S.; Grassi, D.; Hofstadter, Mark; Filacchione, G.; Lee, S.; Giuppi, S.; Janssen, M. A.; Capria, M. T.

doi:10.1016/j.icarus.2012.08.002

Cited by 53 publications

(47 citation statements)

References 39 publications

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“…Delbo et al 2007) and that our midto far-IR data originate in the top layer of the surface. We do not see any signatures of sub-surface layers where the thermal inertia could be significantly higher (Keihm et al 2012).…”

Section: Comparison With Ao and Speckle Resultscontrasting

confidence: 54%

Physical properties of asteroid 308635 (2005 YU₅₅) derived from multi-instrument infrared observations during a very close Earth approach

Müller¹,

Miyata²,

Kiss³

et al. 2013

A&A

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The near-Earth asteroid 308635 (2005 YU 55 ) is a potentially hazardous asteroid which was discovered in 2005 and passed Earth on Nov. 8, 2011 at 0.85 lunar distances. This was the closest known approach by an asteroid of several hundred metres in diameter since 1976 when an object of similar size passed at 0.5 lunar distances. We observed 2005 YU 55 from the ground with a recently developed mid-IR camera (miniTAO/MAX38) in N and Q bands and with the Submillimeter Array (SMA) at 1.3 mm. In addition, we obtained space observations with Herschel/PACS at 70, 100, and 160 μm. Our thermal measurements cover a wide range of wavelengths from 8.9 μm to 1.3 mm and were taken after opposition at phase angles between -97 • and -18 • . We performed a radiometric analysis via a thermophysical model and combined our derived properties with results from radar, adaptive optics, lightcurve observations, speckle, and auxiliary thermal data. We find that 308635 (2005 YU 55 ) has an almost spherical shape with an effective diameter of 300 to 312 m and a geometric albedo p V of 0.055 to 0.075. Its spin axis is oriented towards celestial directions (λ ecl , β ecl ) = (60 • ± 30 • , -60 • ± 15 • ), which means it has a retrograde sense of rotation. The analysis of all available data combined revealed a discrepancy with the radar-derived size. Our radiometric analysis of the thermal data together with the problem to find a unique rotation period might be connected to a non-principal axis rotation. A low to intermediate level of surface roughness (rms mean slope in the range 0.1-0.3) is required to explain the available thermal measurements. We found a thermal inertia in the range 350−800 Jm −2 s −0.5 K −1 , very similar to the rubble-pile asteroid 25 143 Itokawa and indicating a surface with a mixture of low conductivity fine regolith with larger rocks and boulders of high thermal inertia.

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Section: Comparison With Ao and Speckle Resultscontrasting

confidence: 54%

Physical properties of asteroid 308635 (2005 YU₅₅) derived from multi-instrument infrared observations during a very close Earth approach

Müller¹,

Miyata²,

Kiss³

et al. 2013

A&A

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“…For a detailed discussion of the results from mid-IR observations of small bodies carried out by in situ missions such as Dawn and Rosetta, the reader is referred to chapters by Barucci et al and Russel et al (this volume). These missions gathered thermal IR maps of bodies such as (2867) Steins (Leyrat et al 2011), (21) Lutetia, and (4) Vesta (Keihm et al 2012;Tosi et al 2014;Capria et al 2014). …”

Section: The Missionsmentioning

confidence: 99%

Space-Based Thermal Infrared Studies of Asteroids

Mainzer¹,

Usui²,

Trilling³

2015

Asteroids IV

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Large-area surveys operating at mid-infrared wavelengths have proven to be a valuable means of discovering and characterizing minor planets. Through the use of radiometric models, it is possible to derive physical properties such as diameters, albedos, and thermal inertia for large numbers of objects. Modern detector array technology has resulted in a significant improvement in spatial resolution and sensitivity compared with previous generations of spacebased infrared telescopes, giving rise to a commensurate increase in the number of objects that have been observed at these wavelengths. Space-based infrared surveys of asteroids therefore offer an effective method of rapidly gathering information about small body populations orbital and physical properties. The AKARI, WISE/NEOWISE, Spitzer, and Herschel missions have significantly increased the number of minor planets with well-determined diameters and albedos.

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“…The subpixel roughness can be regarded as a measure of the surface irregularity at a scale smaller than the shape model (of the order of 20 m) and larger than the thermal skin depth (of the order of 1 cm, expressed, in the case of the diurnal cycle, as D = √ KP / πρc , where P is the rotation period). It can be interpreted, for example, as the percentage of cratered terrain with respect to flat terrain [ Müller and Lagerros , ; Keihm et al ., ]. High values of the ξ parameter will increase the computed surface temperature, while low values, indicating a flatter surface, will have an opposite effect.…”

Section: Thermophysical Classification Of the Surface Of Vestamentioning

confidence: 99%

Vesta surface thermal properties map

Capria

Tosi

Sanctis

et al. 2014

Geophysical Research Letters

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The first ever regional thermal properties map of Vesta has been derived from the temperatures retrieved by infrared data by the mission Dawn. The low average value of thermal inertia, 30 ± 10 J m À2 s À0.5 K À1, indicates a surface covered by a fine regolith. A range of thermal inertia values suggesting terrains with different physical properties has been determined. The lower thermal inertia of the regions north of the equator suggests that they are covered by an older, more processed surface. A few specific areas have higher than average thermal inertia values, indicative of a more compact material. The highest thermal inertia value has been determined on the Marcia crater, known for its pitted terrain and the presence of hydroxyl in the ejecta. Our results suggest that this type of terrain can be the result of soil compaction following the degassing of a local subsurface reservoir of volatiles.

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Interpretation of combined infrared, submillimeter, and millimeter thermal flux data obtained during the Rosetta fly-by of Asteroid (21) Lutetia

Cited by 53 publications

References 39 publications

Physical properties of asteroid 308635 (2005 YU₅₅) derived from multi-instrument infrared observations during a very close Earth approach

Physical properties of asteroid 308635 (2005 YU₅₅) derived from multi-instrument infrared observations during a very close Earth approach

Space-Based Thermal Infrared Studies of Asteroids

Vesta surface thermal properties map

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Interpretation of combined infrared, submillimeter, and millimeter thermal flux data obtained during the Rosetta fly-by of Asteroid (21) Lutetia

Cited by 53 publications

References 39 publications

Physical properties of asteroid 308635 (2005 YU55) derived from multi-instrument infrared observations during a very close Earth approach

Physical properties of asteroid 308635 (2005 YU55) derived from multi-instrument infrared observations during a very close Earth approach

Space-Based Thermal Infrared Studies of Asteroids

Vesta surface thermal properties map

Contact Info

Product

Resources

About

Physical properties of asteroid 308635 (2005 YU₅₅) derived from multi-instrument infrared observations during a very close Earth approach

Physical properties of asteroid 308635 (2005 YU₅₅) derived from multi-instrument infrared observations during a very close Earth approach