Reanalysis of asteroid families structure through visible spectroscopy

Mothé-Diniz, T.; Roig, F.; Carvano, J. M.

doi:10.1016/j.icarus.2004.10.002

Cited by 130 publications

(184 citation statements)

References 52 publications

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“…Given their origin from a common parent, Themis family members are thought to be compositionally homogeneous, as corroborated by observational studies showing that the family is dominated by primitive C-type asteroids that also exhibit signs of aqueous alteration (Bell 1989;Florczak et al 1999;Ivezić et al 2002;Mothé-Diniz et al 2005). The family is also characterized by a high rate of collisions relative to the general main-belt population (Farinella & Davis 1992;Dell'Oro et al 2001).…”

Section: Survey Designmentioning

confidence: 94%

The Hawaii trails project: comet-hunting in the main asteroid belt

Hsieh

2009

A&A

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Context. The mysterious solar system object 133P/(7968) Elst-Pizarro is dynamically asteroidal, yet displays recurrent comet-like dust emission. Two scenarios were hypothesized to explain this unusual behavior: 1) 133P is a classical comet from the outer solar system that has evolved onto a main-belt orbit or 2) 133P is a dynamically ordinary main-belt asteroid on which subsurface ice has recently been exposed. If 1) is correct, the expected rarity of a dynamical transition onto an asteroidal orbit implies that 133P could be alone in the main belt. In contrast, if 2) is correct, other icy main-belt objects should exist and could also exhibit cometary activity. Aims. Believing 133P to be a dynamically ordinary, yet icy main-belt asteroid, I set out to test the primary prediction of the hypothesis: that 133P-like objects should be common and could be found by an appropriately designed observational survey. Methods. I conducted just such a survey -the Hawaii Trails Project -of selected main-belt asteroids in a search for objects displaying cometary activity. Optical observations were made of targets selected from among the Themis, Koronis, and Veritas asteroid families, the Karin asteroid cluster, and low-inclination, kilometer-scale outer-belt asteroids, using the Lulin 1.0 m, small and moderate aperture research telescope system (SMARTS) 1.0 m, University of Hawaii 2.2 m, southern astrophysical research (SOAR) 4.1 m, Gemini North 8.1 m, Subaru 8.2 m, and Keck I 10 m telescopes. Results. I made 657 observations of 599 asteroids, discovering one active object now known as 176P/LINEAR, leading to the identification of the new cometary class of main-belt comets (MBCs). These results suggest that there could be ∼100 currently active MBCs among low-inclination, kilometer-scale outer-belt asteroids. Physically and statistically, MBC activity is consistent with initiation by meter-sized impactors. The estimated rate of impacts and sizes of resulting active sites, however, imply that 133P-sized bodies should become significantly devolatilized over Gyr timescales, suggesting that 133P, and possibly the other MBCs as well, could be secondary, or even multigenerational, fragments from recent breakup events.

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Section: Survey Designmentioning

confidence: 94%

The Hawaii trails project: comet-hunting in the main asteroid belt

Hsieh

2009

A&A

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“…The main body of a younger subcluster in the Flora family, 1270 Datura was excluded (Vokrouhlicky et al 2009). Both 810 Atossa and 2156 Kate, identified by one of the clustering method and different than S taxonomic type, which are probable interlopers in the Flora family, were also excluded, because asteroid families in the main belt are rather homogenous taxonomically (Cellino et al 2002;Mothe-Diniz et al 2005).…”

Section: Katementioning

confidence: 99%

Do Slivan states exist in the Flora family?

Kryszczyńska

2013

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Context. It is known that the Yarkovsky effect moves small astroids to larger/smaller semimajor axes depending on their prograde/retrograde spins. The YORP effect influences asteroid spin periods and spin axis orientations so that they evolve in time. The alignment of the spin vectors and correlations of the spin rates, now known as Slivan states and observed among members of the Koronis family, are interpreted in terms of the YORP effect and spin-orbit resonances. Splitting asteroid families into prograde and retrograde groups has recently been proposed as a result of the Yarkovsky effect. Prograde and retrograde asteroids drift in different directions, and this has never been observed directly. Aims. The influence of the Yarkovsky and YORP effects should be observable among objects in asteroid families, especially in the Flora family, which lies close to the Sun and consists of many small objects. Methods. The Flora family asteroids were modelled using the lightcurve inversion technique. As a result the orientation of spin vectors, shapes, and sidereal periods of rotation were obtained. Results. Results of modelling of the Flora family asteroids show the family splitting into prograde and retrograde groups as a result of the Yarkovsky effect. The observed ratio between prograde and retrograde asteroids is 2.6. The positions of spin vectors, as well as their similar latitudes suggest, that the Slivan states are observed among the Flora family asteroids. Conclusions. The influence of the Yarkovsky and YORP effect is clearly visible in the Flora family. The location of the Flora family close to the ν 6 resonance explains the lack of retrograde objects and confirms the excess of retrograde rotators among NEAs and their origin from the ν 6 . The Slivan states that I searched seem to be present among prograde rotators in this family even though they were not expected.

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“…Florczak et al (2002) identified (809) Lundia and (956) Elisa as V-type asteroids in the Flora family and suggested that their origin might be in the Vesta family. Mothé-Diniz et al (2005) analyzed the taxonomic types present in asteroid families and clumps in the Flora family. Within the Baptistina family, Mothé-Diniz et al (2005) found objects of classes Xc, X, C, L, S, V, and A, making it one of the most taxonomically diverse families in the study.…”

Section: Introductionmentioning

confidence: 99%

Differentiation signatures in the Flora region

Oszkiewicz

Kankiewicz

Wlodarczyk³

et al. 2015

A&A

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Context. Most asteroid families are very homogeneous in physical properties. Some show greater diversity, however. The Flora family is the most intriguing of them. The Flora family is spread widely in the inner main belt, has a rich collisional history, and is one of the most taxonomically diverse regions in the main belt. As a result of its proximity to the asteroid (4) Vesta (the only currently known intact differentiated asteroid) and its family, migration between the two regions is possible. This dynamical path is one of the counter arguments to the hypothesis that there may be traces of a differentiated parent body other than Vesta in the inner main belt region. We here investigate the possibility that some of the V-and A-types (commonly interpreted as basaltoids and dunites -parts of the mantle and crust of differentiated parent bodies) in the Flora dynamical region are not dynamically connected to Vesta. Aims. The goal of this study is to investigate asteroids in the Flora dynamical region that may be witness to the differentiation of a parent body other than (4) Vesta. In particular, we aim at predicting which asteroids may be fragments of a differentiated body or bodies (taxonomical V-types). We also investigate their possible dynamical linkage to the nearby Vesta family. Methods. To predict the taxonomic types of asteroids we used the naive Bayes classifier. We studied their dynamical past through numerical integration including gravitational and Yarkovsky forces. Each asteroid was cloned, and average orbital elements were computed at each step. When possible, we used observationally constrained physical parameters for the thermal forces. Results. Most of the asteroids in the Flora region are predicted to originate from the S-complex (around 47.8%). Tens of asteroids with potentially differential origins are identified in the region, including 164 potential V-types. We investigated the dynamical evolution of selected objects to examine possible linkages of selected asteroids with the nearby Vesta family. In addition to the candidate differentiated objects, we also studied the dynamical evolution of those asteroids from the Flora family for which spectroscopic classification exist. In particular, we used all the physical parameters available for asteroid (809) Lundia to show that the asteroid is unlikely to originate in the Vesta region and that it resided on a stable orbit in the Flora dynamical region for at least 80 My. Its observationally constrained prograde rotation shows that asteroid (809) Lundia is unlikely to be a former Vesta family member. Conclusions. We found that the V-type candidates are plentiful in the Flora dynamical region. Dynamical investigations of selected objects showed that some of these objects were likely not connected to asteroid (4) Vesta and its family for at least 100 My. This adds another piece of evidence to the hypothesis that there are multiple differentiated parent bodies.

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Reanalysis of asteroid families structure through visible spectroscopy

Cited by 130 publications

References 52 publications

The Hawaii trails project: comet-hunting in the main asteroid belt

The Hawaii trails project: comet-hunting in the main asteroid belt

Do Slivan states exist in the Flora family?

Differentiation signatures in the Flora region

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