The Minor planet bulletin最新文献

Observations from the South Africa node of the Korea Microlensing Telescope Network (KMTNe-SAAO) were analyzed using the open source Photometry Pipeline (PP). PP can identify serendipitously observed asteroids in the observation fields which led to the extraction of 53 asteroid lightcurves. Rotational periods for 49 of these targets could be determined and are presented here.

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.

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 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, P_SID) = (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.

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 or might be radar targets. 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 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 P_ORB = 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.

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

Photometric observations of the near-Earth asteroid (31345) 1998 PG by Pravec et al. (2000) found a rotation period of 2.51620 h. Also found was a secondary period of 7.0035 h, or the double-period of 14.007 h, possibly indicating an additional body in the system. An extended campaign by the authors in 2018 lead to a similar primary period of 2.5168 h. However, instead of a 7-hour secondary period, one of about 16 hours was found with the lightcurve showing apparent mutual events (occultations and/or eclipses). The data sets from 1998 and 2018 could not be fit to a secondary period near the one found at the opposing apparition. The conclusion is that the asteroid is very likely binary, but - other than the primary rotation period - the system's parameters are ill-defined and only future observations will sufficiently refine them.