Rotation-Resolved Spectroscopy of a Very Young Asteroid, (1270) Datura

Takato, Naruhisa

doi:10.1086/592569

Cited by 8 publications

(8 citation statements)

References 18 publications

(24 reference statements)

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“…Our best-fit model values are H 0 (R) = 12.03 ± 0.02, at the maximum of the lightcurve, and G(R) = 0.29 ± 0.01. We used data from 1991 (Wisniewski et al 1997; with the derived V − R value), /2008 and 2009 (Simeiz), see Table 2.…”

Section: Discussionmentioning

confidence: 99%

“…We started our photometric campaign during the 2006 opposition and continued during subsequent observing time opportunities. Our main efforts were concentrated on the 2007/2008 opposition when observations covering a period of nearly six months, and phase angle values of up to 26 • , were obtained (we did not use the independent observations of Takato (2008) from mid February 2008 because they roughly coincided with our data from the beginning of February 2008). These observations were very important because they allowed easy linkage of data from all oppositions and helped us to resolve the asteroid shape.…”

Section: Observationsmentioning

confidence: 99%

“…Spectroscopic studies with the goal of calibrating space weathering processes and spectral uniformity as a function of the rotational cycle are ongoing (Mothé-Diniz & Nesvorný 2008;Takato 2008;Chapman et al 2009;Vernazza et al 2009). Here we begin attempts to characterize the rotational state of the young families' members.…”

Section: Introductionmentioning

confidence: 99%

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Datura family: the 2009 update

Vokrouhlický¹,

Ďurech²,

Michałowski

et al. 2009

A&A

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Context. Research of asteroid families has been recently refreshed by the discovery of very young ones. These families are of great interest because they represent the product of their parent body fragmentation before orbital and physical evolutionary processes can change them. A cluster of seven objects around the largest body (1270) Datura is of particular interest because it has enough known members and resides in the inner part of the main asteroid belt, facilitating observations. Aims. We carried out photometric observations of the two largest members of the Datura family -asteroids (1270) Datura and (90265) 2003 CL5 -with the goal of inferring their physical parameters. We also used numerous astrometric observations of Datura-family members in the past few years to revisit the age of this cluster. Methods. We performed numerous photometric observations of (1270) Datura over several oppositions. We then used the lightcurve inversion method to determine the spin state and shape of this asteroid. In the case of (90265) 2003 CL5, for which only limited lightcurve data have been acquired so far, we used Fourier analysis to determine the synodic rotation period during the 2008 apparition. We also used backward numerical integration of the improved orbits of Datura family members to reduce uncertainty in its age. Results. We determined the rotation state of (1270) Datura, the largest member of its own family. Its major properties are a short rotation period of ∼3.36 h and small obliquity, which, however, exhibits ∼±15 • excursions because of a forced Cassini state of the proper nodal frequency. Any possible initial non-principal rotation state has probably been damped and the asteroid rotates about the shortest axis of the inertia tensor. Its global shape, although convex in our representation, may reflect regions related to the excavation of the family members from the parent body surface. Interestingly, the second largest member of the Datura family -(90265) 2003 CL5 -appears to be very slow rotator with the rotation period ∼24 h. The large amplitude of its rotation curve suggests that its shape is extremely elongated, possibly bi-lobed. Improved orbits of the family members allow us to re-determine the possible age of this family. We find an age that is slightly older than previously reported. Using a conservative approach, we obtain an age in the 450 to 600 kyr range. With strengthened, but plausible, conditions, we find that the current data may support an age of 530±20 kyr. Further astrometric and photometric observations of the Datura cluster members are needed to determine its age more accurately.

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Section: Discussionmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

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Datura family: the 2009 update

Vokrouhlický¹,

Ďurech²,

Michałowski

et al. 2009

A&A

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“…On the other hand there are claims of faster surface weathering time scales such as Takato's (2008) upper limit of 450 kyr based on a shallow 1 lm absorption band observed on (1270) Datura. However, we expect that the space weathering phenomenon is a relatively subtle effect easily masked by stochastic variations between asteroids due to, i.e.…”

Section: Introductionmentioning

confidence: 99%

Using the youngest asteroid clusters to constrain the space weathering and gardening rate on S-complex asteroids

Willman

Jedicke

Moskovitz³

et al. 2010

Icarus

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a b s t r a c tWe have extended our earlier work on space weathering of the youngest S-complex asteroid families to include results from asteroid clusters with ages <10 6 years and to newly identified asteroid pairs with ages <5 Â 10 5 years. We have identified three S-complex asteroid clusters amongst the set of clusters with ages in the range 10 5-6 years-(1270) Datura, (21509) Lucascavin and (16598) 1992 YC2. The average color of the objects in these clusters agrees with the color predicted by the space weathering model of Willman et al. (Willman, M., Jedicke, R., Nesvorný , D., Moskovitz, N., Ivezić , Z., Fevig, R. [2008]. Icarus 195, 663-673). SDSS five-filter photometry of the members of the very young asteroid pairs with ages <10 5 years was used to determine their taxonomic classification. Their types are consistent with the background population near each object. The average color of the S-complex pairs is PC 1 = 0.49 ± 0.03, over 5r redder than predicted by Willman et al. (Willman, M., Jedicke, R., Nesvorný , D., Moskovitz, N., Ivezić , Z., Fevig, R. [2008]. Icarus 195,[663][664][665][666][667][668][669][670][671][672][673]. This may indicate that the most likely pair formation mechanism is a gentle separation due to YORP spin-up leaving much of the aged and reddened surface undisturbed. If this is the case then our color measurement allows us to set an upper limit of $64% on the amount of surface disturbed in the separation process. Using pre-existing color data and our new results for the youngest S-complex asteroid clusters we have extended our space weather model to explicitly include the effects of regolith gardening and fit separate weathering and gardening characteristic time scales of s w = 960 ± 160 Myr and s g = 2000 ± 290 Myr respectively. The first principal component color for fresh S-complex material is PC 1 = 0.37 ± 0.01 while the maximum amount of local reddening is DPC 1 = 0.33 ± 0.06. Our first-ever determination of the gardening time is in stark contrast to our calculated gardening time of s g $ 270 Myr based on main belt impact rates and reasonable assumptions about crater and ejecta blanket sizes. A possible resolution for the discrepancy is through a 'honeycomb' mechanism in which the surface regolith structure absorbs small impactors without producing significant ejecta. This mechanism could also account for the paucity of small craters on (433) Eros.

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“…The affinity to Sq and Q sub-class is interesting as it may fit the young exposed surfaces of the family members. A detailed spectral observation of (1270) Datura itself by Takato (2008) revealed no spectral variations over a rotation cycle. Moreover, analysis of depth of the ∼0.95 µm absorption band, indicating degree of space weathering, revealed an evolved surface similar to that of old S-type asteroids.…”

Section: Introductionmentioning

confidence: 94%

The young Datura asteroid family

Vokrouhlický

Pravec

Ďurech

et al. 2017

A&A

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Context. Asteroid families are the outcomes of disruption or cratering events on a size and energy scales that are not reproducible in laboratory experiments. Overall structure, as well as properties of individual members, in the old families could have been changed since their formation. Therefore young families preserve best the characteristics of the initial event. Aims. We study the most suitable known asteroid family with an age of less than 1 Myr, the Datura family. We aim (i) to obtain information about rotation state and shape of the largest members in the family; and (ii) to constrain its debiased population down to couple of hundreds of meters in size. Methods. We have analyzed the up-to-date catalog of orbital elements of main belt asteroids. We evaluated the detection efficiency of Catalina Sky Survey (CSS) in regard to detections of members in the Datura family, and we have used our photometric observations and lightcurve inversion methods to determine the rotation states and shapes of the largest members of the family. Results. We determined rotation periods of the seven largest members of the Datura family, and we also derived accurate mean absolute magnitudes for six of them. Except for the largest fragment (1270) Datura, the asteroids tend to have long rotation periods and large amplitude of the lightcurve, witnessing an elongated shape. For the four largest asteroids, our observations allow us to resolve rotation pole and a rough shape. All of them are prograde-rotating and have the latitude of the rotation pole >50 • . Our search in orbital catalogs resulted in the discovery of many small, sub-kilometer members of the Datura family. Using the CSS detection efficiency, we inverted this information into the debiased population of Datura family members. We show that the mass and angular momentum content in small fragments is negligible compared to the largest fragment (1270) Datura. These findings may help to constrain the formation mechanism of the family.

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Rotation-Resolved Spectroscopy of a Very Young Asteroid, (1270) Datura

Cited by 8 publications

References 18 publications

Datura family: the 2009 update

Datura family: the 2009 update

Using the youngest asteroid clusters to constrain the space weathering and gardening rate on S-complex asteroids

The young Datura asteroid family

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