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Complete lightcurves of 17 asteroids belonging to the Themis, Eos, and Maria families have been obtained, as well as single-night photometric observations of eight objects belonging to the same families. Using also data previously available in the literature, we perform a preliminary statistical analysis aimed at detecting possible correlations between rotational periods, overall lightcurve amplitudes, and objetcs' sizes. No evident correlation was found, with the possible exception of a weak anticorrelation between size and spin period. The implications of this possible anticorrelation are discussed.

The results of new CCD observations are presented as part of the campaign we are performing in Brazil to measure rotational periods for small asteroids. The observations presented here have been acquired at the Pico dos Dias Observatory between 1997 and 2002 and result in 48 single night lightcurves for 20 asteroids, most of them Main-Belt objects with D < 40 km. We present the rotation periods – ranging from about 3 to 18 hr – along with the composite lightcurve obtained for each observed object.

We present the results concerning Mars-crossing and Near-Earth asteroids of our Small Solar System Objects Spectroscopic Survey - S 3 OS 2 , carried out at the ESO (La Silla, Chile). Thirty-four objects, twenty-two Mars-crossing and twelve NEAs, have been observed from November 1996 through September 2001 in the wavelength range of 4900-9200 A. Most (twenty-seven out of thirty-four) of the objects of our sample fall in the "S-complex", including the S, Sa, Sk, Sl, Sq and A classes, as introduced by Bus (1999). The spectra of these objects resemble that of some ordinary chondrite meteorites. In spite of the small number of objects, we found also in our sample members of the C, Ld, V and X classes.

We report the results of new photometric observations of 19 main-belt asteroids, most of them of small size, i.e., km. The observations were carried out at the do Pico dos Dias D [ 50 Observatoc rio (Brazil) and at the de Bosque Alegre (Argentina), providing more than 50 singleEstacioc n Astrofic sica night light curves. The obtained rotation periods, ranging from 3.2 to 11.5 hr, are presented along with the corresponding composite light curves.

We observed 29 Hungaria and 31 Phocaea asteroids at the European Southern Observatory (Chile) in the wavelength range 4900–9200A . The Phocaea and the Hungaria are both high-inclination groups, located at the inner edge of the main belt near the ν 5 , ν 6 , and ν 16 secular resonances. We confirm that the Hungaria group is composed mainly of E-type asteroids but with a relatively large number of S-types. The Phocaea group, on the other hand, is composed mainly of S-type asteroids. We discuss the possible implications of the observed composition distribution on the origin and evolution of these high-inclination groups.

We observed 44 Eunomia family members at ESO (European Southern Observatory) and at CASLEO (Complejo Astronomico El Leoncito) in the wavelength range of 4900–9200 A. We found 41 objects with the same characteristics: a maximum around λ=7500 A, and a reflectivity gradient spanning a continuous but limited range. Only 3 objects display featureless spectra similar to C-type asteroids, and these should be considered as interlopers. The spectra of the 41 objects show a similarity which is consistent with the dynamical hypothesis of a common origin. On the other hand, the spread of distribution of surface composition also indicates that the Eunomia family was possibly formed from the fragmentation of a partially differentiated S-type parent body.

We present spectroscopic observations of 36 as- teroids, members of the Themis family. These observations were carried on at the European Southern Observatory in the wavelength range 4900 9200 A. Most of the objects present a spectra similar to C-type asteroids and some of them present indicative of aqueous alteration. We discuss the implications of these results on the formation and evo- lution of this family.

The final selection of the two Rosetta target asteroids will be made in a successive phase of the Rosetta project development, when the engineering parameters will be frozen. In this paper we present spectroscopic observations of the possible Rosetta candidates and we discuss the results obtained, particularly the definition of their compositional type. We examine the possibility to select some more “primitive” candidates. On the basis of its size and spectral type, we suggest including the asteroid 140 Siwa as one of the asteroid targets of the Rosetta mission.

The results of photometric observations of comet/asteroid 2060 Chiron at the Observatorio do Pico dos Dias (Brazil-OPD) and the Observatoire de Haute-Provence (France-OHP) during 1994 and 1995 are presented. The analysis of the data shows a decrease of 2060 Chiron brightness from its peak values of 1988–1991. The absolute magnitude, Hv, varies from a maximum of 6.6 in February 1994 up to a minimum of 6.8 in June 1995. Therefore 2060 Chiron is back to a minimum of activity close to that of 1983–1985. The slope parameter G is found to be G = 0.71 ± 0.15. It is suggested that the H-G magnitude system, generally adopted to present 2060 Chiron brightness, is not the most appropriate due to the cometary activity of this object.

The observational programme on small asteroids (diameter less than about 50 km) is continued to enlarge the available dataset of small asteroids. The results are presented of CCD observations of nine small asteroids ( D ≤23 km), performed in France with the 1.2 m telescope at Haute Provence Observatory and with the 2 m telescope at Pic du Midi Observatory. A total of 27 single night lightcurves for nine asteroids were obtained. All the objects were observed for the first time and rotational periods have been determined for all of the observed asteroids: 1992 Galvarino ( P syn = 7 h .004), 2419 Moldavia ( P syn = 2 h .412), 2921 Sophocles ( P syn = 4 h .778), 3247 Di Martino ( P syn = 5 h .445), 3623 Chaplin ( P syn = 8 h .361), 3986 Rozhkovskij ( P syn = 4 h .26), 4436 1983 EX ( P syn = 6 h .656), 5046 1981 DQ ( P syn = 6 h .050) and 1992 YG3 ( P syn = 8 h .91).

CCD photometry of the NEAR mission fly-by target 253 Mathilde is presented. Measurements taken during 52 nights of observations, from February to June 1995, allow a rotation period of 17.406±0.010 days and a lightcurve amplitude of 0.45±0.02 mag to be determined. A B-V color index of 0.67±0.02 and a V-R of 0.35±0.02 are measured, which are compatible with C-type membership. The determination of the phase relation results in H = 10.28±0.03 and G = 0.12±0.06. Indications that the lightcurve is not strictly singly-periodic are found. A power-spectrum analysis detects a secondary frequency f 2 = 0.0322±0.0010 d −1 , which is interpreted as evidence for a complex rotation state.

The Apollo asteroid 4179 Toutatis passed within 0.0242 AU of Earth in December 1992, and photometry was obtained by observers from at least 25 sites around the world, at solar phase angles between 121° and 0.2°. The phase curve is well described in the H, G system with a mean H of 15.3 and a slope parameter G of 0.10 ± 0.10. However, the rotational lightcurve is very unusual. The amplitude is large (1.2 magnitudes) and the rotation period is extremely long (several days). Most remarkably, the lightcurve does not appear to be periodic: it is unlikely that a single rotation period can account for the lightcurve even when the rapidly changing viewing and illumination geometry during the close Earth approach is taken into account, though strong lightcurve minima recurred approximately every 7.3 days. The likely explanation is that Toutatis has complex, tumbling, rotation with a characteristic period between 3 and 7 days. As noted by A. W. Harris (1994 Icarus 107, 209-211), the damping time scale from complex to simple rotation for a small, slowly rotating asteroid like Toutatis is so long that complex rotation is expected, but Toutatis is the first asteroid to show such strong observational evidence for complex rotation.

A program of physical studies of asteroids has been carried out using two types of detectors: photoelectric photometer and CCD camera. In this paper we report the results of photometric observations of 10 asteroids. We have obtained a total of 35 single night lightcurves and we have determined rotational periods for the asteroids 1520 Imatra (P = 5.23 h), 1534 Nasi (P = 9.75 h), 2078 Nanking (P = 6.473 h), 2241 Alcathous (P = 9.41 h), 3103 1982 BB (P= 5.709 h), 3139 Shantou (P = 8.33 h), 3259 Brownlee (P = 9.24 h), 4455 Ruriko (P = 4.23 h).

Groundbased photometric observations of asteroid 243 Ida over seven apparitions from 1980 to 1993 allow us to derive a model for its spin vector and shape prior to the August 1993 encounter by the Galileo spacecraft. Two equally likely solutions for the spin vector are at ecliptic coordinates (1950) λp1 = 73, βp1 = -53 or λp2 = 254, βp2 = -55 with an uncertainty of ± 10° in each coordinate. Ida's low orbital inclination restricts the available aspect angles for Earth-based observers so that the spin vector ambiguity cannot be resolved. We offer predictions for the flyby geometry for both solutions, where the Galileo spacecraft images will resolve this ambiguity easily. Ida's rotation is retrograde with a sidereal period of 4.633632 ± 0.000007 hr. Assuming a triaxial ellipsoid model, we estimate axial ratios of a/b = 1.82 ± 0.10 and b/c = 1.15 ± 0.10. The morphology of the observed lightcurves suggest that Ida has a nonuniform albedo distribution, but we cannot completely rule out observational uncertainties or simplifying model assumptions (e.g., convex shape, geometric scattering) as sources for this suggestion. It is not possible to predict uniquely the distribution of any such albedo variegation.

FEC gain in DC-coupled burst mode receivers is limited because of a variance in BER between bursts. This BER variance is characterized in an XG-PON1 upstream prototype. It is shown that basic BER tests overestimate the FEC gain.