NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2019 JULY-SEPTEMBER.

Lightcurves for 28 near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2019 July to September were analyzed for rotation period, peak-to-peak amplitude, and signs of satellites or tumbling. 2059 Baboquivari, (90403) 2003 YE45, and 2016 AU130 are candidates for membership within the very wide binary asteroids class. The 2019 data led to a seemingly unambiguous period of 4.7906 h for (441987) 2010 NY65, which overturned previous results that have now been updated.

LIGHTCURVE ANALYSIS OF HILDA ASTEROIDS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2018 SEPTEBER - 2019 SEPTEMBER.

CCD photometric observations of three Hilda asteroids were made at the Center for Solar System Studies (CS3) in 2019 September. Analysis of the 2019 data for 4495 Dassanowsky, a reported binary (Warner and Stephens, 2019), found three periods, one being very long (431 h). The long period and a secondary one made it a potential member of the very wide binary asteroids but, for the first time for a member of this class, a third period seems to be present. A review of the 2018 data set using comparison star magnitudes from the ATLAS catalog (Tonry et al., 2018) found the previously unnoticed very long period. The secondary and tertiary periods were still in good agreement with the original two-period solution found in 2018. Though the odds are remote and considerable more data are required, the new results from the 2018 data are encouraging in the on-going effort to find evidence that validates claims of the existence of the very wide binary asteroid class.

LIGHTCURVE ANALYSIS OF L4 TROJAN ASTERIODS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2019 JULY TO SEPTEMBER.

Lightcurves for 11 L4 Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 July to September.

MAIN-BELT ASTEROIDS OBSERVED FROM CS3: 2019 JULY TO SEPTEMBER.

CCD photometric observations of 25 main-belt asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 July to September.

ASTEROID LIGHTCURVE ANALYSIS AT CS3-PALMER DIVIDE STATION: 2018 JULY-SEPTEMBER.

Lightcurves for 12 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2018 July-September. Analysis of a larger amplitude lightcurve in 2018 for 5175 Ables lead to new analysis and results for earlier apparitions. The Hungaria asteroid (37378) 2001 VU76 is possibly a super-fast rotator with a period and size that put it just above the so-called "spin barrier."

7002 BRONSHTEN: A NEW MARS-CROSSING BINARY.

CCD photometric observations of the Mars-crosser asteroid 7002 Bronshten show it to be a binary system. The primary period is P1 = 2.67025 ± 0.00007 h. The orbital period of the satellite, which is also its rotation period, is PORB = 13.323 ± 0.003 h. The mutual event attenuations in the satellite lightcurve are 0.06-0.11 mag. This establishes a lower limit of the secondary-to-primary mean diameter ratio of 0.24 ± 0.02.

LIGHTCURVE ANALYSIS OF L4 TROJAN ASTERIODS AT THE CENTER FOR SOLAR SYSTEM STUDIES - 2018 JULY TO SEPTEMBER.

Lightcurves for five Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2018 July to September.

ANOTHER TRIO OF POSSIBLE VERY WIDE BINARY ASTEROIDS.

Lightcurve analysis of the near-Earth asteroids (442742) 2012 WP3, (523604) 2004 QB17, and 2018 RL indicate that they are potential members of a relatively rare class of "very wide binary asteroids." These objects feature a primary rotational period of tens to hundreds of hours and a secondary rotational period less than 24 hours, usually less than 10 hours. These three bring to 30 the number of suspected members of the class.

(12538) 1998 OH: A CONTINUING NON-RESOLUTION.

CCD photometric observations at the Center for Solar System Studies (CS3) were made of the near-Earth asteroid (12538) 1998 OH in 2018 November. The goal was to find a secure period and so resolve ambiguous solutions from previous years. Final analysis of the 2018 data found that it is anything but ordinary. One possibility is that it is a low-amplitude, fast-rotating tumbler. The other, more exotic, possibility is that it may be an asteroid pair in the making, i.e., the two fast-rotating components have not yet broken their mutual bond. Future observations may show that one of these, or yet another solution, correctly describes the asteroid.

MAIN-BELT ASTEROIDS OBSERVED FROM CS3: 2018 OCTOBER - DECEMBER.

CCD photometric observations of 18 main-belt asteroids were obtained from the Center for Solar System Studies from 2018 October to December. A pole solution was found for 4910 Kawasato of (λ, ß, PSID) = (355°, 35°, 4.66271 h). (31320) 1998 HX2 is a binary asteroid with a P1 of 2.8149 ± 0.0001 h and P2 of 47.06 ± 0.05 h.

LIGHTCURVE ANALYSIS OF HILDA ASTEROIDS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2019 JANUARY-MARCH.

CCD photometric observations of three Hilda asteroids were made at the Center for Solar System Studies (CS3) from 2019 January-March. For 1038 Tuckia, the period solution was ambiguous at either P = 18.020 h, amplitude 0.22 mag or P = 14.401 h, amplitude 0.20 mag. For 2246 Bowell, the analysis found P = 4.997 and amplitude 0.46 mag. For 4317 Garibaldi, we found a dual-period solution with P1 = 17.843 or 8.92 h and P2 = 11.426 h. The shorter value for P1 is similar to previously reported results but this is the first time a true dual-period solution, i.e., not an ambiguous single period solution, has been reported.

NEAR-EARTH ASTEROID (152931) 2000 EA107: A PROBABLE BINARY.

CCD photometric observations of the near-Earth asteroid (152931) 2000 EA107 were made in 2019 March and April at the Center for Solar System Studies (CS3). Analysis of the data found that the asteroid is likely a binary. The primary period is P 1 = 4.1367 ± 0.0002 h with a lightcurve amplitude of A 1 = 0.29 ± 0.02 mag. The secondary period is P 2 = 16.079 ± 0.006 h with a lightcurve amplitude of A 2 = 0.16 ± 0.01 mag. No mutual events (occultations and/or eclipses) were seen to confirm the presence of a satellite.

LIGHTCURVE ANALYSIS OF L5 TROJAN ASTERIODS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2019 ARPIL TO JUNE.

Lightcurves for five L5 Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 April to June.

LIGHTCURVE ANALYSIS OF HILDA ASTEROIDS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2019 APRIL-JUNE.

CCD photometric observations of seven Hilda asteroids were made at the Center for Solar System Studies (CS3) from 2019 April and June. Analysis of data for 1269 Rollandia and 3843 OISCA based on 2019 data led to review of our earlier results. For both objects, this resulted not in solving but deepening the mystery of the their true rotation periods.

NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2019 MARCH-JULY.

Lightcurves for 38 near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2019 March-July were analyzed for rotation period, peak-to-peak amplitude, and signs of satellites or tumbling.

MAIN-BELT ASTEROIDS OBSERVED FROM CS3: 2019 APRIL TO JUNE.

CCD photometric observations of 19 main-belt asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 April to June.

NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS AT THE CENTER FOR SOLAR SYSTEM STUDIES: 2018 JULY-SEPTEMBER.

Lightcurves for 45 Near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2018 July-September were analyzed for rotation period and signs of satellites or tumbling. NEA 13553 Massakikoyama appears to be in non-principal axis rotation, i.e., tumbling. 2011 UA (D = 0.6 km) is a super-fast rotator with a period of 0.316391 ± 0.000007 h. The period and size place it well above the spin barrier. The period for 2018 RQ2 is multiply ambiguous, with possible solutions of 4.28 h or 5.17 h (monomdal lightcurve) and 8.58 h or 10.60 h (bimodal lightcurve). 2018 KE3 may be a binary asteroid.