Lightcurves for four Hilda asteroids were obtained at the Center for Solar System Studies (CS3) from 2016 December thru 2017 April.
We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and have no or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.
CCD photometric observations of 25 main-belt asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 July to September.
Lightcurves for four L5 Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 January to March. The suspected binary Trojan, 2207 Antenor was observed again and a single attenuation event was detected.
Lightcurves for 32 near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2018 September-December were analyzed for rotation period and signs of satellites or tumbling.
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."
Lightcurves for four Hilda asteroids were obtained at the Center for Solar System Studies (CS3) from 2018 September-November: 3514 Hooke, 3557 Sokolsky, 4495 Dassanowksy, and 10331 Peterbluhm. 4495 Dassanowksy appears to be a binary asteroid with a primary period of either 2.6314 hr or 5.263 hr and an orbital period of 18.516 hr. The secondary-to-primary ratio of the effective diameters is 0.26 ± 0.02.
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.
We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and have no or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.
CCD photometric observations of the inner main-belt asteroid (20882) 2000 VH57 were made from 2018 Sept. 15 through Oct. 20. Analysis of the data showed that the asteroid is binary with a primary rotational period of 2.5586 hr and a satellite orbital period of 32.81 hr. Mutual eclipse/occultation events indicate a lower limit on the secondary-to-primary mean diameter ratio (Ds/Dp) of 0.23. During the period of observations, the primary and secondary lightcurves evolved as the viewing aspect changed. In particular, the depth of the secondary event increased significantly towards the end of the observations.
CCD photometric observations of 10 main-belt asteroids were obtained from the Center for Solar System Studies from 2019 January to March. In light of recent period analysis, images of 2120 Tyumenia obtained in 2004 were re-examined. The resulting analysis found a period of 17.515 h, which is consistent with the recent results.
We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and have no or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.
CCD photometric observations of four main-belt and one near-Earth asteroid were made in 2019. Of these, the Vestoid 2602 Moore and Hungaria (27568) 2000 PT6 were confirmed to be binary asteroids. The Hungaria 3880 Kaiserman is a suspected binary. Near-Earth asteroid (142040) 2002 QE15 was found to have a long period (46.4 h). Re-evaluation of data for the asteroid from two previous apparitions found a secondary period that is consistent with the system being a candidate for the rare class of very wide binary asteroids. New analysis of the data from 2016 for Phocaea member 2937 Gibbs found two periods (the second being ambiguous). It could not be determined if the asteroid is binary or in a tumbling state.
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.
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 P1 = 4.1367 ± 0.0002 h with a lightcurve amplitude of A1 = 0.29 ± 0.02 mag. The secondary period is P2 = 16.079 ± 0.006 h with a lightcurve amplitude of A2 = 0.16 ± 0.01 mag. No mutual events (occultations and/or eclipses) were seen to confirm the presence of a satellite.
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, β, 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.
CCD photometric observations of 19 main-belt asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 April to June.
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.
