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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2009.02.005 Byline: Francesca E. DeMeo (a), Richard P. Binzel (b), Stephen M. Slivan (b), Schelte J. Bus (c) Keywords: Asteroids; Spectroscopy Abstract: The availability of asteroid spectral measurements extending to the near-infrared, resulting from the development of new telescopic instruments (such as SpeX [Rayner, J.T., and 7 colleagues, 2003. Astron. Soc. Pacific 115, 362-382]), provides a new basis for classifying asteroid reflectance spectra. We present an asteroid taxonomy classification system based on reflectance spectrum characteristics for 371 asteroids measured over the wavelength range 0.45 to 2.45 [mu]m. This system of 24 classes is constructed using principal component analysis, following most closely the visible wavelength taxonomy of Bus [Bus, S.J., 1999. Ph.D. thesis, Massachusetts Institute of Technology], which itself builds upon the system of Tholen [Tholen, D.J., 1984. Ph.D. thesis, University of Arizona]. Nearly all of the Bus taxonomy classes are preserved, with one new class (Sv) defined. For each class we present boundary definitions, spectral descriptions, and prototype examples. A flow chart method is presented for classifying newly acquired data spanning this wavelength range. When data are available only in the near-infrared range (0.85 to 2.45 [mu]m), classification is also possible in many cases through an alternate flow chart process. Within our sample, several classes remain relatively rare: only 6 objects fall into the A-class; 349 Dembowska and 3628 Boznemcova reside as the only objects in their respective R- and O-classes. Eight Q-class objects are all near-Earth asteroids. We note 1904 Massevitch as an outer main-belt V-type while 15 other V-type objects have inner main-belt orbits consistent with an association with Vesta. Author Affiliation: (a) LESIA, Observatoire de Paris, F-92195 Meudon Principal Cedex, France (b) Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States (c) Institute for Astronomy, 640 N. Aohoku Place, Hilo, HI 96720, United States Article History: Received 30 October 2008; Revised 6 February 2009; Accepted 9 February 2009

Abstract: We recorded 101 new rotation lightcurves of five Koronis family members, and then combined the new observations with previous data to determine the objects'' sidereal rotation periods, spin vector orientations, and model shape solutions. The observing program was tailored specifically for spin vector analyses by determining single-apparition Lumme–Bowell solar phase coefficients, and by measuring synodic rotation periods precisely enough to unambiguously count the rotations between two consecutive oppositions, which is a prerequisite for identifying the correct sidereal period. The new data make possible first pole and shape determinations for (263) Dresda, (462) Eriphyla, and (1289) Kutaïssi, and they improve the models for (277) Elvira and (534) Nassovia, two objects previously studied by Slivan et al. [Slivan, S.M., Binzel, R.P., Crespo da Silva, L.D., Kaasalainen, M., Lyndaker, M.M., Krčo, M., 2003. Icarus 162, 285–307]. Our results increase the number of Koronis family spin vectors reported in the literature to fourteen, a sample which now includes the seven largest family members. The spin properties of Eriphyla (rotation period , spin vector obliquity ) and Kutaïssi (, ) are consistent with the markedly nonrandom distribution reported by Slivan [Slivan, S.M., 2002. Nature 419, 49–51], and explained by Vokrouhlický et al. [Vokrouhlický, D., Nesvorný, D., Bottke, W.F., 2003. Nature 425, 147–151] as the result of the effects of thermal “YORP” torques combined with solar and planetary gravitational torques. Dresda (, ) is the first prograde Koronis member whose spin obliquity and spin rate significantly differ from the clustered spin properties previously found for other prograde Koronis members; nevertheless, its spin vector is consistent with several of the spin evolution possibilities that were identified in the YORP modeling. [Copyright &y& Elsevier]

Abstract: We report the results of an observational survey of rotation lightcurves for members of the Koronis asteroid family that we conducted using CCD imaging cameras at seven different observatories during the period 1998–2005. A total of 375 individual lightcurves yield new or refined rotation periods for the 24 survey objects (658) Asteria, (761) Brendelia, (811) Nauheima, (975) Perseverantia, (1029) La Plata, (1079) Mimosa, (1100) Arnica, (1245) Calvinia, (1336) Zeelandia, (1350) Rosselia, (1423) Jose, (1482) Sebastiana, (1618) Dawn, (1635) Bohrmann, (1725) CrAO, (1741) Giclas, (1742) Schaifers, (1848) Delvaux, (1955) McMath, (2123) Vltava, (2144) Marietta, (2224) Tucson, (2729) Urumqi, and (2985) Shakespeare. Most of the data have been calibrated to standard magnitudes. Several previously unpublished lightcurves recorded using a photoelectric photometer during the period 1987–1989 are also reported here. We present composite lightcurves and report derived synodic rotation periods. For those objects with sufficient coverage in solar phase angle we also determined Lumme–Bowell solar phase parameters, and for four objects we obtained colors. Our results reduce selection biases among known rotation lightcurve parameters for Koronis family members by completing the sample down to , and they lay the foundation for future spin vector and shape determinations. The distribution of rotation rates in the available sample of Koronis members is non-Maxwellian at a confidence level of 99%. It also seems to be qualitatively consistent with the effects of long-term modification by thermal YORP torques, as proposed by Vokrouhlický et al. [Vokrouhlický, D., Nesvorný, D., Bottke, W.F., 2003. Nature 425, 147–151] to explain the distribution of the ten Koronis member spin vectors that have already been determined [Slivan, S.M., 2002. Nature 419, 49–51; Slivan, S.M., Binzel, R.P., Crespo da Silva, L.D., Kaasalainen, M., Lyndaker, M.M., Krčo, M., 2003. Icarus 162, 285–307]. [Copyright &y& Elsevier]